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* Introduce cpu_dcache_is_aliasing() across all architecturesMathieu Desnoyers2024-02-221-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce a generic way to query whether the data cache is virtually aliased on all architectures. Its purpose is to ensure that subsystems which are incompatible with virtually aliased data caches (e.g. FS_DAX) can reliably query this. For data cache aliasing, there are three scenarios dependending on the architecture. Here is a breakdown based on my understanding: A) The data cache is always aliasing: * arc * csky * m68k (note: shared memory mappings are incoherent ? SHMLBA is missing there.) * sh * parisc B) The data cache aliasing is statically known or depends on querying CPU state at runtime: * arm (cache_is_vivt() || cache_is_vipt_aliasing()) * mips (cpu_has_dc_aliases) * nios2 (NIOS2_DCACHE_SIZE > PAGE_SIZE) * sparc32 (vac_cache_size > PAGE_SIZE) * sparc64 (L1DCACHE_SIZE > PAGE_SIZE) * xtensa (DCACHE_WAY_SIZE > PAGE_SIZE) C) The data cache is never aliasing: * alpha * arm64 (aarch64) * hexagon * loongarch (but with incoherent write buffers, which are disabled since commit d23b7795 ("LoongArch: Change SHMLBA from SZ_64K to PAGE_SIZE")) * microblaze * openrisc * powerpc * riscv * s390 * um * x86 Require architectures in A) and B) to select ARCH_HAS_CPU_CACHE_ALIASING and implement "cpu_dcache_is_aliasing()". Architectures in C) don't select ARCH_HAS_CPU_CACHE_ALIASING, and thus cpu_dcache_is_aliasing() simply evaluates to "false". Note that this leaves "cpu_icache_is_aliasing()" to be implemented as future work. This would be useful to gate features like XIP on architectures which have aliasing CPU dcache-icache but not CPU dcache-dcache. Use "cpu_dcache" and "cpu_cache" rather than just "dcache" and "cache" to clarify that we really mean "CPU data cache" and "CPU cache" to eliminate any possible confusion with VFS "dentry cache" and "page cache". Link: https://lore.kernel.org/lkml/20030910210416.GA24258@mail.jlokier.co.uk/ Link: https://lkml.kernel.org/r/20240215144633.96437-9-mathieu.desnoyers@efficios.com Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches") Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Russell King <linux@armlinux.org.uk> Cc: Alasdair Kergon <agk@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: kernel test robot <lkp@intel.com> Cc: Michael Sclafani <dm-devel@lists.linux.dev> Cc: Mike Snitzer <snitzer@kernel.org> Cc: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: add pte_batch_hint() to reduce scanning in folio_pte_batch()Ryan Roberts2024-02-221-7/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some architectures (e.g. arm64) can tell from looking at a pte, if some follow-on ptes also map contiguous physical memory with the same pgprot. (for arm64, these are contpte mappings). Take advantage of this knowledge to optimize folio_pte_batch() so that it can skip these ptes when scanning to create a batch. By default, if an arch does not opt-in, folio_pte_batch() returns a compile-time 1, so the changes are optimized out and the behaviour is as before. arm64 will opt-in to providing this hint in the next patch, which will greatly reduce the cost of ptep_get() when scanning a range of contptes. Link: https://lkml.kernel.org/r/20240215103205.2607016-16-ryan.roberts@arm.com Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Acked-by: David Hildenbrand <david@redhat.com> Tested-by: John Hubbard <jhubbard@nvidia.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Barry Song <21cnbao@gmail.com> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Morse <james.morse@arm.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: thp: batch-collapse PMD with set_ptes()Ryan Roberts2024-02-221-25/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Refactor __split_huge_pmd_locked() so that a present PMD can be collapsed to PTEs in a single batch using set_ptes(). This should improve performance a little bit, but the real motivation is to remove the need for the arm64 backend to have to fold the contpte entries. Instead, since the ptes are set as a batch, the contpte blocks can be initially set up pre-folded (once the arm64 contpte support is added in the next few patches). This leads to noticeable performance improvement during split. Link: https://lkml.kernel.org/r/20240215103205.2607016-3-ryan.roberts@arm.com Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Barry Song <21cnbao@gmail.com> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Morse <james.morse@arm.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/memory: optimize unmap/zap with PTE-mapped THPDavid Hildenbrand2024-02-221-26/+66
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Similar to how we optimized fork(), let's implement PTE batching when consecutive (present) PTEs map consecutive pages of the same large folio. Most infrastructure we need for batching (mmu gather, rmap) is already there. We only have to add get_and_clear_full_ptes() and clear_full_ptes(). Similarly, extend zap_install_uffd_wp_if_needed() to process a PTE range. We won't bother sanity-checking the mapcount of all subpages, but only check the mapcount of the first subpage we process. If there is a real problem hiding somewhere, we can trigger it simply by using small folios, or when we zap single pages of a large folio. Ideally, we had that check in rmap code (including for delayed rmap), but then we cannot print the PTE. Let's keep it simple for now. If we ever have a cheap folio_mapcount(), we might just want to check for underflows there. To keep small folios as fast as possible force inlining of a specialized variant using __always_inline with nr=1. Link: https://lkml.kernel.org/r/20240214204435.167852-11-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/mmu_gather: improve cond_resched() handling with large folios and ↵David Hildenbrand2024-02-221-15/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | expensive page freeing In tlb_batch_pages_flush(), we can end up freeing up to 512 pages or now up to 256 folio fragments that span more than one page, before we conditionally reschedule. It's a pain that we have to handle cond_resched() in tlb_batch_pages_flush() manually and cannot simply handle it in release_pages() -- release_pages() can be called from atomic context. Well, in a perfect world we wouldn't have to make our code more complicated at all. With page poisoning and init_on_free, we might now run into soft lockups when we free a lot of rather large folio fragments, because page freeing time then depends on the actual memory size we are freeing instead of on the number of folios that are involved. In the absolute (unlikely) worst case, on arm64 with 64k we will be able to free up to 256 folio fragments that each span 512 MiB: zeroing out 128 GiB does sound like it might take a while. But instead of ignoring this unlikely case, let's just handle it. So, let's teach tlb_batch_pages_flush() that there are some configurations where page freeing is horribly slow, and let's reschedule more frequently -- similarly like we did for now before we had large folio fragments in there. Avoid yet another loop over all encoded pages in the common case by handling that separately. Note that with page poisoning/zeroing, we might now end up freeing only a single folio fragment at a time that might exceed the old 512 pages limit: but if we cannot even free a single MAX_ORDER page on a system without running into soft lockups, something else is already completely bogus. Freeing a PMD-mapped THP would similarly cause trouble. In theory, we might even free 511 order-0 pages + a single MAX_ORDER page, effectively having to zero out 8703 pages on arm64 with 64k, translating to ~544 MiB of memory: however, if 512 MiB doesn't result in soft lockups, 544 MiB is unlikely to result in soft lockups, so we won't care about that for the time being. In the future, we might want to detect if handling cond_resched() is required at all, and just not do any of that with full preemption enabled. Link: https://lkml.kernel.org/r/20240214204435.167852-10-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/mmu_gather: add __tlb_remove_folio_pages()David Hildenbrand2024-02-223-14/+74
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add __tlb_remove_folio_pages(), which will remove multiple consecutive pages that belong to the same large folio, instead of only a single page. We'll be using this function when optimizing unmapping/zapping of large folios that are mapped by PTEs. We're using the remaining spare bit in an encoded_page to indicate that the next enoced page in an array contains actually shifted "nr_pages". Teach swap/freeing code about putting multiple folio references, and delayed rmap handling to remove page ranges of a folio. This extension allows for still gathering almost as many small folios as we used to (-1, because we have to prepare for a possibly bigger next entry), but still allows for gathering consecutive pages that belong to the same large folio. Note that we don't pass the folio pointer, because it is not required for now. Further, we don't support page_size != PAGE_SIZE, it won't be required for simple PTE batching. We have to provide a separate s390 implementation, but it's fairly straight forward. Another, more invasive and likely more expensive, approach would be to use folio+range or a PFN range instead of page+nr_pages. But, we should do that consistently for the whole mmu_gather. For now, let's keep it simple and add "nr_pages" only. Note that it is now possible to gather significantly more pages: In the past, we were able to gather ~10000 pages, now we can also gather ~5000 folio fragments that span multiple pages. A folio fragment on x86-64 can span up to 512 pages (2 MiB THP) and on arm64 with 64k in theory 8192 pages (512 MiB THP). Gathering more memory is not considered something we should worry about, especially because these are already corner cases. While we can gather more total memory, we won't free more folio fragments. As long as page freeing time primarily only depends on the number of involved folios, there is no effective change for !preempt configurations. However, we'll adjust tlb_batch_pages_flush() separately to handle corner cases where page freeing time grows proportionally with the actual memory size. Link: https://lkml.kernel.org/r/20240214204435.167852-9-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/mmu_gather: define ENCODED_PAGE_FLAG_DELAY_RMAPDavid Hildenbrand2024-02-221-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Nowadays, encoded pages are only used in mmu_gather handling. Let's update the documentation, and define ENCODED_PAGE_BIT_DELAY_RMAP. While at it, rename ENCODE_PAGE_BITS to ENCODED_PAGE_BITS. If encoded page pointers would ever be used in other context again, we'd likely want to change the defines to reflect their context (e.g., ENCODED_PAGE_FLAG_MMU_GATHER_DELAY_RMAP). For now, let's keep it simple. This is a preparation for using the remaining spare bit to indicate that the next item in an array of encoded pages is a "nr_pages" argument and not an encoded page. Link: https://lkml.kernel.org/r/20240214204435.167852-7-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/mmu_gather: pass "delay_rmap" instead of encoded page to ↵David Hildenbrand2024-02-221-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __tlb_remove_page_size() We have two bits available in the encoded page pointer to store additional information. Currently, we use one bit to request delay of the rmap removal until after a TLB flush. We want to make use of the remaining bit internally for batching of multiple pages of the same folio, specifying that the next encoded page pointer in an array is actually "nr_pages". So pass page + delay_rmap flag instead of an encoded page, to handle the encoding internally. Link: https://lkml.kernel.org/r/20240214204435.167852-6-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/memory: factor out zapping folio pte into zap_present_folio_pte()David Hildenbrand2024-02-221-21/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | Let's prepare for further changes by factoring it out into a separate function. Link: https://lkml.kernel.org/r/20240214204435.167852-5-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/memory: further separate anon and pagecache folio handling in ↵David Hildenbrand2024-02-221-5/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | zap_present_pte() We don't need up-to-date accessed-dirty information for anon folios and can simply work with the ptent we already have. Also, we know the RSS counter we want to update. We can safely move arch_check_zapped_pte() + tlb_remove_tlb_entry() + zap_install_uffd_wp_if_needed() after updating the folio and RSS. While at it, only call zap_install_uffd_wp_if_needed() if there is even any chance that pte_install_uffd_wp_if_needed() would do *something*. That is, just don't bother if uffd-wp does not apply. Link: https://lkml.kernel.org/r/20240214204435.167852-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/memory: handle !page case in zap_present_pte() separatelyDavid Hildenbrand2024-02-221-11/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We don't need uptodate accessed/dirty bits, so in theory we could replace ptep_get_and_clear_full() by an optimized ptep_clear_full() function. Let's rely on the provided pte. Further, there is no scenario where we would have to insert uffd-wp markers when zapping something that is not a normal page (i.e., zeropage). Add a sanity check to make sure this remains true. should_zap_folio() no longer has to handle NULL pointers. This change replaces 2/3 "!page/!folio" checks by a single "!page" one. Note that arch_check_zapped_pte() on x86-64 checks the HW-dirty bit to detect shadow stack entries. But for shadow stack entries, the HW dirty bit (in combination with non-writable PTEs) is set by software. So for the arch_check_zapped_pte() check, we don't have to sync against HW setting the HW dirty bit concurrently, it is always set. Link: https://lkml.kernel.org/r/20240214204435.167852-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/memory: factor out zapping of present pte into zap_present_pte()David Hildenbrand2024-02-221-41/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "mm/memory: optimize unmap/zap with PTE-mapped THP", v3. This series is based on [1]. Similar to what we did with fork(), let's implement PTE batching during unmap/zap when processing PTE-mapped THPs. We collect consecutive PTEs that map consecutive pages of the same large folio, making sure that the other PTE bits are compatible, and (a) adjust the refcount only once per batch, (b) call rmap handling functions only once per batch, (c) perform batch PTE setting/updates and (d) perform TLB entry removal once per batch. Ryan was previously working on this in the context of cont-pte for arm64, int latest iteration [2] with a focus on arm6 with cont-pte only. This series implements the optimization for all architectures, independent of such PTE bits, teaches MMU gather/TLB code to be fully aware of such large-folio-pages batches as well, and amkes use of our new rmap batching function when removing the rmap. To achieve that, we have to enlighten MMU gather / page freeing code (i.e., everything that consumes encoded_page) to process unmapping of consecutive pages that all belong to the same large folio. I'm being very careful to not degrade order-0 performance, and it looks like I managed to achieve that. While this series should -- similar to [1] -- be beneficial for adding cont-pte support on arm64[2], it's one of the requirements for maintaining a total mapcount[3] for large folios with minimal added overhead and further changes[4] that build up on top of the total mapcount. Independent of all that, this series results in a speedup during munmap() and similar unmapping (process teardown, MADV_DONTNEED on larger ranges) with PTE-mapped THP, which is the default with THPs that are smaller than a PMD (for example, 16KiB to 1024KiB mTHPs for anonymous memory[5]). On an Intel Xeon Silver 4210R CPU, munmap'ing a 1GiB VMA backed by PTE-mapped folios of the same size (stddev < 1%) results in the following runtimes for munmap() in seconds (shorter is better): Folio Size | mm-unstable | New | Change --------------------------------------------- 4KiB | 0.058110 | 0.057715 | - 1% 16KiB | 0.044198 | 0.035469 | -20% 32KiB | 0.034216 | 0.023522 | -31% 64KiB | 0.029207 | 0.018434 | -37% 128KiB | 0.026579 | 0.014026 | -47% 256KiB | 0.025130 | 0.011756 | -53% 512KiB | 0.024292 | 0.010703 | -56% 1024KiB | 0.023812 | 0.010294 | -57% 2048KiB | 0.023785 | 0.009910 | -58% [1] https://lkml.kernel.org/r/20240129124649.189745-1-david@redhat.com [2] https://lkml.kernel.org/r/20231218105100.172635-1-ryan.roberts@arm.com [3] https://lkml.kernel.org/r/20230809083256.699513-1-david@redhat.com [4] https://lkml.kernel.org/r/20231124132626.235350-1-david@redhat.com [5] https://lkml.kernel.org/r/20231207161211.2374093-1-ryan.roberts@arm.com This patch (of 10): Let's prepare for further changes by factoring out processing of present PTEs. Link: https://lkml.kernel.org/r/20240214204435.167852-1-david@redhat.com Link: https://lkml.kernel.org/r/20240214204435.167852-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: linuxppc-dev@lists.ozlabs.org Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: compaction: limit the suitable target page order to be less than cc->orderBaolin Wang2024-02-221-1/+3
| | | | | | | | | | | | | | | | | | It can not improve the fragmentation if we isolate the target free pages exceeding cc->order, especially when the cc->order is less than pageblock_order. For example, suppose the pageblock_order is MAX_ORDER (size is 4M) and cc->order is 2M THP size, we should not isolate other 2M free pages to be the migration target, which can not improve the fragmentation. Moreover this is also applicable for large folio compaction. Link: https://lkml.kernel.org/r/afcd9377351c259df7a25a388a4a0d5862b986f4.1705928395.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/hugetlb: move page order check inside hugetlb_cma_reserve()Anshuman Khandual2024-02-221-0/+7
| | | | | | | | | | | | | | | | All platforms could benefit from page order check against MAX_PAGE_ORDER before allocating a CMA area for gigantic hugetlb pages. Let's move this check from individual platforms to generic hugetlb. Link: https://lkml.kernel.org/r/20240209054221.1403364-1-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/mglru: improve swappiness handlingKinsey Ho2024-02-221-10/+10
| | | | | | | | | | | | | | | | The reclaimable number of anon pages used to set initial reclaim priority is only based on get_swappiness(). Use can_reclaim_anon_pages() to include NUMA node demotion. Also move the swappiness handling of when !__GFP_IO in try_to_shrink_lruvec() into isolate_folios(). Link: https://lkml.kernel.org/r/20240214060538.3524462-6-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Donet Tom <donettom@linux.vnet.ibm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/mglru: improve struct lru_gen_mm_walkKinsey Ho2024-02-221-24/+26
| | | | | | | | | | | | | | | Rename max_seq to seq in struct lru_gen_mm_walk to keep consistent with struct lru_gen_mm_state. Note that seq is not always up to date with max_seq from lru_gen_folio. No functional changes. Link: https://lkml.kernel.org/r/20240214060538.3524462-5-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Donet Tom <donettom@linux.vnet.ibm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/mglru: improve reset_mm_stats()Kinsey Ho2024-02-221-20/+22
| | | | | | | | | | | | | | | | | struct lruvec* is already a field of struct lru_gen_mm_walk. Remove the parameter struct lruvec* into functions that already have access to struct lru_gen_mm_walk*. Also, we do not need to handle reset histogram stats when !should_walk_mmu(). Remove the call to reset_mm_stats() in iterate_mm_list_nowalk(). Link: https://lkml.kernel.org/r/20240214060538.3524462-4-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Donet Tom <donettom@linux.vnet.ibm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/mglru: improve should_run_aging()Kinsey Ho2024-02-221-14/+11
| | | | | | | | | | | | | | | | scan_control *sc does not need to be passed into should_run_aging(), as it provides only the reclaim priority. This can be moved to get_nr_to_scan(). Refactor should_run_aging() and get_nr_to_scan() to improve code readability. No functional changes. Link: https://lkml.kernel.org/r/20240214060538.3524462-3-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Donet Tom <donettom@linux.vnet.ibm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/mglru: drop unused parameterKinsey Ho2024-02-221-5/+5
| | | | | | | | | | | | | | | | | | | | | | Patch series "mm/mglru: code cleanup and refactoring" This provides MGLRU code cleanup and refactoring for better readability. This patch (of 5): struct scan_control *sc is currently passed into try_to_inc_max_seq() and run_aging(). This parameter is not used. Drop the unused parameter struct scan_control *sc. No functional change. Link: https://lkml.kernel.org/r/20240214060538.3524462-1-kinseyho@google.com Link: https://lkml.kernel.org/r/20240214060538.3524462-2-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Donet Tom <donettom@linux.vnet.ibm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* kasan/test: avoid gcc warning for intentional overflowArnd Bergmann2024-02-221-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The out-of-bounds test allocates an object that is three bytes too short in order to validate the bounds checking. Starting with gcc-14, this causes a compile-time warning as gcc has grown smart enough to understand the sizeof() logic: mm/kasan/kasan_test.c: In function 'kmalloc_oob_16': mm/kasan/kasan_test.c:443:14: error: allocation of insufficient size '13' for type 'struct <anonymous>' with size '16' [-Werror=alloc-size] 443 | ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL); | ^ Hide the actual computation behind a RELOC_HIDE() that ensures the compiler misses the intentional bug. Link: https://lkml.kernel.org/r/20240212111609.869266-1-arnd@kernel.org Fixes: 3f15801cdc23 ("lib: add kasan test module") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Marco Elver <elver@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/zswap: optimize and cleanup the invalidation of duplicate entryChengming Zhou2024-02-221-18/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We may encounter duplicate entry in the zswap_store(): 1. swap slot that freed to per-cpu swap cache, doesn't invalidate the zswap entry, then got reused. This has been fixed. 2. !exclusive load mode, swapin folio will leave its zswap entry on the tree, then swapout again. This has been removed. 3. one folio can be dirtied again after zswap_store(), so need to zswap_store() again. This should be handled correctly. So we must invalidate the old duplicate entry before inserting the new one, which actually doesn't have to be done at the beginning of zswap_store(). The good point is that we don't need to lock the tree twice in the normal store success path. And cleanup the loop as we are here. Note we still need to invalidate the old duplicate entry when store failed or zswap is disabled , otherwise the new data in swapfile could be overwrite by the old data in zswap pool when lru writeback. Link: https://lkml.kernel.org/r/20240209044112.3883835-1-chengming.zhou@linux.dev Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Yosry Ahmed <yosryahmed@google.com> Acked-by: Chris Li <chrisl@kernel.org> Acked-by: Nhat Pham <nphamcs@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: compaction: refactor compact_node()Kefeng Wang2024-02-221-44/+21
| | | | | | | | | | Refactor compact_node() to handle both proactive and synchronous compact memory, which cleanups code a bit. Link: https://lkml.kernel.org/r/20240208013607.1731817-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/cma: add sysfs file 'release_pages_success'Anshuman Khandual2024-02-223-0/+21
| | | | | | | | | | | | | | | | | | | | | | | | This adds the following new sysfs file tracking the number of successfully released pages from a given CMA heap area. This file will be available via CONFIG_CMA_SYSFS and help in determining active CMA pages available on the CMA heap area. This adds a new 'nr_pages_released' (CONFIG_CMA_SYSFS) into 'struct cma' which gets updated during cma_release(). /sys/kernel/mm/cma/<cma-heap-area>/release_pages_success After this change, an user will be able to find active CMA pages available in a given CMA heap area via the following method. Active pages = alloc_pages_success - release_pages_success That's valuable information for both software designers, and system admins as it allows them to tune the number of CMA pages available in the system. This increases user visibility for allocated CMA area and its utilization. Link: https://lkml.kernel.org/r/20240206045731.472759-1-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/demotion: print demotion targetsLi Zhijian2024-02-221-1/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, when a demotion occurs, it will prioritize selecting a node from the preferred targets as the destination node for the demotion. If the preferred node does not meet the requirements, it will try from all the lower memory tier nodes until it finds a suitable demotion destination node or ultimately fails. However, the demotion target information isn't exposed to the users, especially the preferred target information, which relies on more factors. This makes it hard for users to understand the exact demotion behavior. Rather than having a new sysfs interface to expose this information, printing directly to kernel messages, just like the current page allocation fallback order does. A dmesg example with this patch is as follows: [ 0.704860] Demotion targets for Node 0: null [ 0.705456] Demotion targets for Node 1: null // node 2 is onlined [ 32.259775] Demotion targets for Node 0: perferred: 2, fallback: 2 [ 32.261290] Demotion targets for Node 1: perferred: 2, fallback: 2 [ 32.262726] Demotion targets for Node 2: null // node 3 is onlined [ 42.448809] Demotion targets for Node 0: perferred: 2, fallback: 2-3 [ 42.450704] Demotion targets for Node 1: perferred: 2, fallback: 2-3 [ 42.452556] Demotion targets for Node 2: perferred: 3, fallback: 3 [ 42.454136] Demotion targets for Node 3: null // node 4 is onlined [ 52.676833] Demotion targets for Node 0: perferred: 2, fallback: 2-4 [ 52.678735] Demotion targets for Node 1: perferred: 2, fallback: 2-4 [ 52.680493] Demotion targets for Node 2: perferred: 4, fallback: 3-4 [ 52.682154] Demotion targets for Node 3: null [ 52.683405] Demotion targets for Node 4: null // node 5 is onlined [ 62.931902] Demotion targets for Node 0: perferred: 2, fallback: 2-5 [ 62.938266] Demotion targets for Node 1: perferred: 5, fallback: 2-5 [ 62.943515] Demotion targets for Node 2: perferred: 4, fallback: 3-4 [ 62.947471] Demotion targets for Node 3: null [ 62.949908] Demotion targets for Node 4: null [ 62.952137] Demotion targets for Node 5: perferred: 3, fallback: 3-4 Regarding this requirement, we have previously discussed [1]. The initial proposal involved introducing a new sysfs interface. However, due to concerns about potential changes and compatibility issues with the interface in the future, a consensus was not reached with the community. Therefore, this time, we are directly printing out the information. [1] https://lore.kernel.org/all/d1d5add8-8f4a-4578-8bf0-2cbe79b09989@fujitsu.com/ Link: https://lkml.kernel.org/r/20240206020151.605516-1-lizhijian@fujitsu.com Signed-off-by: Li Zhijian <lizhijian@fujitsu.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/damon/sysfs: handle 'state' file inputs for every sampling interval if ↵SeongJae Park2024-02-223-16/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | possible DAMON sysfs interface need to access kdamond-touching data for some of kdamond user commands. It uses ->after_aggregation() kdamond callback to safely access the data in the case. It had to use the aggregation interval callback because that was the only callback that users can access complete monitoring results. Since patch series "mm/damon: provide pseudo-moving sum based access rate", which starts from commit 78fbfb155d20 ("mm/damon/core: define and use a dedicated function for region access rate update"), DAMON provides good-to-use quality moitoring results for every sampling interval. It aims to help users who need to quickly retrieve the monitoring results. When the aggregation interval is set too long and therefore waiting for the aggregation interval can degrade user experience, or when the access pattern is expected to be significantly changed[1] could be such cases. However, because DAMON sysfs interface is still handling the commands per aggregation interval, the end user cannot get the benefit. Update DAMON sysfs interface to handle kdamond commands for every sampling interval if applicable. Specifically, all kdamond data accessing commands except 'commit' command are applicable. [1] https://lore.kernel.org/r/20240129121316.GA9706@cuiyangpei Link: https://lkml.kernel.org/r/20240206025158.203097-1-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: xiongping1 <xiongping1@xiaomi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: hugetlb: improve the handling of hugetlb allocation failure for freed or ↵Baolin Wang2024-02-221-16/+16
| | | | | | | | | | | | | | | | | | | | | | | | in-use hugetlb alloc_and_dissolve_hugetlb_folio() preallocates a new hugetlb page before it takes hugetlb_lock. In 3 out of 4 cases the page is not really used and therefore the newly allocated page is just freed right away. This is wasteful and it might cause pre-mature failures in those cases. Address that by moving the allocation down to the only case (hugetlb page is really in the free pages pool). We need to drop hugetlb_lock to do so and therefore need to recheck the page state after regaining it. The patch is more of a cleanup than an actual fix to an existing problem. There are no known reports about pre-mature failures. Link: https://lkml.kernel.org/r/62890fd60b1ecd5bf1cdc476c973f60fe37aa0cb.1707181934.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Muchun Song <muchun.song@linux.dev> Cc: David Hildenbrand <david@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/migrate: preserve exact soft-dirty statePaul Gofman2024-02-221-2/+5
| | | | | | | | | | | | | | | | | | | | pte_mkdirty() sets both _PAGE_DIRTY and _PAGE_SOFT_DIRTY bits. The _PAGE_SOFT_DIRTY can get set even if it wasn't set on original page before migration. This makes non-soft-dirty pages soft-dirty just because of migration/compaction. Clear the _PAGE_SOFT_DIRTY flag if it wasn't set on original page. By definition of soft-dirty feature, there can be spurious soft-dirty pages because of kernel's internal activity such as VMA merging or migration/compaction. This patch is eliminating the spurious soft-dirty pages because of migration/compaction. Link: https://lkml.kernel.org/r/20240206084838.34560-1-usama.anjum@collabora.com Signed-off-by: Paul Gofman <pgofman@codeweavers.com> Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com> Acked-by: Andrei Vagin <avagin@gmail.com> Cc: Michał Mirosław <emmir@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/zswap: zswap entry doesn't need refcount anymoreChengming Zhou2024-02-221-52/+11
| | | | | | | | | | | | | | | | | | | | | | Since we don't need to leave zswap entry on the zswap tree anymore, we should remove it from tree once we find it from the tree. Then after using it, we can directly free it, no concurrent path can find it from tree. Only the shrinker can see it from lru list, which will also double check under tree lock, so no race problem. So we don't need refcount in zswap entry anymore and don't need to take the spinlock for the second time to invalidate it. The side effect is that zswap_entry_free() maybe not happen in tree spinlock, but it's ok since nothing need to be protected by the lock. Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-6-99d4084260a0@bytedance.com Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Reviewed-by: Nhat Pham <nphamcs@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/zswap: only support zswap_exclusive_loads_enabledChengming Zhou2024-02-222-27/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The !zswap_exclusive_loads_enabled mode will leave compressed copy in the zswap tree and lru list after the folio swapin. There are some disadvantages in this mode: 1. It's a waste of memory since there are two copies of data, one is folio, the other one is compressed data in zswap. And it's unlikely the compressed data is useful in the near future. 2. If that folio is dirtied, the compressed data must be not useful, but we don't know and don't invalidate the trashy memory in zswap. 3. It's not reclaimable from zswap shrinker since zswap_writeback_entry() will always return -EEXIST and terminate the shrinking process. On the other hand, the only downside of zswap_exclusive_loads_enabled is a little more cpu usage/latency when compression, and the same if the folio is removed from swapcache or dirtied. More explanation by Johannes on why we should consider exclusive load as the default for zswap: Caching "swapout work" is helpful when the system is thrashing. Then recently swapped in pages might get swapped out again very soon. It certainly makes sense with conventional swap, because keeping a clean copy on the disk saves IO work and doesn't cost any additional memory. But with zswap, it's different. It saves some compression work on a thrashing page. But the act of keeping compressed memory contributes to a higher rate of thrashing. And that can cause IO in other places like zswap writeback and file memory. And the A/B test results of the kernel build in tmpfs with limited memory can support this theory: !exclusive exclusive real 63.80 63.01 user 1063.83 1061.32 sys 290.31 266.15 workingset_refault_anon 2383084.40 1976397.40 workingset_refault_file 44134.00 45689.40 workingset_activate_anon 837878.00 728441.20 workingset_activate_file 4710.00 4085.20 workingset_restore_anon 732622.60 639428.40 workingset_restore_file 1007.00 926.80 workingset_nodereclaim 0.00 0.00 pgscan 14343003.40 12409570.20 pgscan_kswapd 0.00 0.00 pgscan_direct 14343003.40 12409570.20 pgscan_khugepaged 0.00 0.00 Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-5-99d4084260a0@bytedance.com Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Acked-by: Yosry Ahmed <yosryahmed@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Nhat Pham <nphamcs@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/zswap: remove duplicate_entry debug valueChengming Zhou2024-02-221-8/+1
| | | | | | | | | | | | | | | | | | | | | | | | | cat /sys/kernel/debug/zswap/duplicate_entry 2086447 When testing, the duplicate_entry value is very high, but no warning message in the kernel log. From the comment of duplicate_entry "Duplicate store was encountered (rare)", it seems something goes wrong. Actually it's incremented in the beginning of zswap_store(), which found its zswap entry has already on the tree. And this is a normal case, since the folio could leave zswap entry on the tree after swapin, later it's dirtied and swapout/zswap_store again, found its original zswap entry. So duplicate_entry should be only incremented in the real bug case, which already have "WARN_ON(1)", it looks redundant to count bug case, so this patch just remove it. Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-4-99d4084260a0@bytedance.com Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Nhat Pham <nphamcs@gmail.com> Acked-by: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/zswap: stop lru list shrinking when encounter warm regionChengming Zhou2024-02-222-1/+6
| | | | | | | | | | | | | | | When the shrinker encounter an existing folio in swap cache, it means we are shrinking into the warmer region. We should terminate shrinking if we're in the dynamic shrinker context. This patch add LRU_STOP to support this, to avoid overshrinking. Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-3-99d4084260a0@bytedance.com Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Nhat Pham <nphamcs@gmail.com> Reviewed-by: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/zswap: invalidate zswap entry when swap entry freeChengming Zhou2024-02-223-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | During testing I found there are some times the zswap_writeback_entry() return -ENOMEM, which is not we expected: bpftrace -e 'kr:zswap_writeback_entry {@[(int32)retval]=count()}' @[-12]: 1563 @[0]: 277221 The reason is that __read_swap_cache_async() return NULL because swapcache_prepare() failed. The reason is that we won't invalidate zswap entry when swap entry freed to the per-cpu pool, these zswap entries are still on the zswap tree and lru list. This patch moves the invalidation ahead to when swap entry freed to the per-cpu pool, since there is no any benefit to leave trashy zswap entry on the tree and lru list. With this patch: bpftrace -e 'kr:zswap_writeback_entry {@[(int32)retval]=count()}' @[0]: 259744 Note: large folio can't have zswap entry for now, so don't bother to add zswap entry invalidation in the large folio swap free path. Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-2-99d4084260a0@bytedance.com Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Reviewed-by: Nhat Pham <nphamcs@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/zswap: add more comments in shrink_memcg_cb()Chengming Zhou2024-02-221-17/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "mm/zswap: optimize zswap lru list", v2. This series is motivated when observe the zswap lru list shrinking, noted there are some unexpected cases in zswap_writeback_entry(). bpftrace -e 'kr:zswap_writeback_entry {@[(int32)retval]=count()}' There are some -ENOMEM because when the swap entry is freed to per-cpu swap pool, it doesn't invalidate/drop zswap entry. Then the shrinker encounter these trashy zswap entries, it can't be reclaimed and return -ENOMEM. So move the invalidation ahead to when swap entry freed to the per-cpu swap pool, since there is no any benefit to leave trashy zswap entries on the zswap tree and lru list. Another case is -EEXIST, which is seen more in the case of !zswap_exclusive_loads_enabled, in which case the swapin folio will leave compressed copy on the tree and lru list. And it can't be reclaimed until the folio is removed from swapcache. Changing to zswap_exclusive_loads_enabled mode will invalidate when folio swapin, which has its own drawback if that folio is still clean in swapcache and swapout again, we need to compress it again. Please see the commit for details on why we choose exclusive load as the default for zswap. Another optimization for -EEXIST is that we add LRU_STOP to support terminating the shrinking process to avoid evicting warmer region. Testing using kernel build in tmpfs, one 50GB swapfile and zswap shrinker_enabled, with memory.max set to 2GB. mm-unstable zswap-optimize real 63.90s 63.25s user 1064.05s 1063.40s sys 292.32s 270.94s The main optimization is in sys cpu, about 7% improvement. This patch (of 6): Add more comments in shrink_memcg_cb() to describe the deref dance which is implemented to fix race problem between lru writeback and swapoff, and the reason why we rotate the entry at the beginning. Also fix the stale comments in zswap_writeback_entry(), and add more comments to state that we only deref the tree after we get the swapcache reference. Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-0-99d4084260a0@bytedance.com Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-1-99d4084260a0@bytedance.com Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Suggested-by: Yosry Ahmed <yosryahmed@google.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Yosry Ahmed <yosryahmed@google.com> Reviewed-by: Nhat Pham <nphamcs@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* memory tier: make memory_tier_subsys constRicardo B. Marliere2024-02-221-1/+1
| | | | | | | | | | | | Now that the driver core can properly handle constant struct bus_type, move the memory_tier_subsys variable to be a constant structure as well, placing it into read-only memory which can not be modified at runtime. Link: https://lkml.kernel.org/r/20240204-bus_cleanup-mm-v1-1-00f49286f164@marliere.net Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/vmscan: make too_many_isolated return boolHao Ge2024-02-221-3/+3
| | | | | | | | | | too_many_isolated() should return bool as does the similar too_many_isolated() in mm/compaction.c. Link: https://lkml.kernel.org/r/20240205042618.108140-1-gehao@kylinos.cn Signed-off-by: Hao Ge <gehao@kylinos.cn> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/cma: make MAX_CMA_AREAS = CONFIG_CMA_AREASAnshuman Khandual2024-02-221-3/+3
| | | | | | | | | | | | There is no real difference between the global area, and other additionally configured CMA areas via CONFIG_CMA_AREAS that always defaults without user input. This makes MAX_CMA_AREAS same as CONFIG_CMA_AREAS, also incrementing its default values, thus maintaining current default for MAX_CMA_AREAS both for UMA and NUMA systems. Link: https://lkml.kernel.org/r/20240205051929.298559-1-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/cma: drop CONFIG_CMA_DEBUGAnshuman Khandual2024-02-222-18/+0
| | | | | | | | | | | | | | | | | All pr_debug() prints in (mm/cma.c) could be enabled via standard Makefile based method. Besides cma_debug_show_areas() should always be called during cma_alloc() failure path. This seemingly redundant config, CONFIG_CMA_DEBUG can be dropped without any problem. [lukas.bulwahn@gmail.com: remove debug code to removed CONFIG_CMA_DEBUG] Link: https://lkml.kernel.org/r/20240207143825.986-1-lukas.bulwahn@gmail.com Link: https://lkml.kernel.org/r/20240205031647.283510-1-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* kasan: rename test_kasan_module_init to kasan_test_module_initTiezhu Yang2024-02-221-2/+2
| | | | | | | | | | | | | | After commit f7e01ab828fd ("kasan: move tests to mm/kasan/"), the test module file is renamed from lib/test_kasan_module.c to mm/kasan/kasan_test_module.c, in order to keep consistent, rename test_kasan_module_init to kasan_test_module_init. Link: https://lkml.kernel.org/r/20240205060925.15594-3-yangtiezhu@loongson.cn Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Acked-by: Marco Elver <elver@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/hugetlb: restore the reservation if neededBreno Leitao2024-02-221-0/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "mm/hugetlb: Restore the reservation", v2. This is a fix for a case where a backing huge page could stolen after madvise(MADV_DONTNEED). A full reproducer is in selftest. See https://lore.kernel.org/all/20240105155419.1939484-1-leitao@debian.org/ In order to test this patch, I instrumented the kernel with LOCKDEP and KASAN, and run the following tests, without any regression: * The self test that reproduces the problem * All mm hugetlb selftests SUMMARY: PASS=9 SKIP=0 FAIL=0 * All libhugetlbfs tests PASS: 0 86 FAIL: 0 0 This patch (of 2): Currently there is a bug that a huge page could be stolen, and when the original owner tries to fault in it, it causes a page fault. You can achieve that by: 1) Creating a single page echo 1 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages 2) mmap() the page above with MAP_HUGETLB into (void *ptr1). * This will mark the page as reserved 3) touch the page, which causes a page fault and allocates the page * This will move the page out of the free list. * It will also unreserved the page, since there is no more free page 4) madvise(MADV_DONTNEED) the page * This will free the page, but not mark it as reserved. 5) Allocate a secondary page with mmap(MAP_HUGETLB) into (void *ptr2). * it should fail, but, since there is no more available page. * But, since the page above is not reserved, this mmap() succeed. 6) Faulting at ptr1 will cause a SIGBUS * it will try to allocate a huge page, but there is none available A full reproducer is in selftest. See https://lore.kernel.org/all/20240105155419.1939484-1-leitao@debian.org/ Fix this by restoring the reserved page if necessary. These are the condition for the page restore: * The system is not using surplus pages. The goal is to reduce the surplus usage for this case. * If the VMA has the HPAGE_RESV_OWNER flag set, and is PRIVATE. This is safely checked using __vma_private_lock() * The page is anonymous Once this is scenario is found, set the `hugetlb_restore_reserve` bit in the folio. Then check if the resv reservations need to be adjusted later, done later, after the spinlock, since the vma_xxxx_reservation() might touch the file system lock. Link: https://lkml.kernel.org/r/20240205191843.4009640-1-leitao@debian.org Link: https://lkml.kernel.org/r/20240205191843.4009640-2-leitao@debian.org Signed-off-by: Breno Leitao <leitao@debian.org> Suggested-by: Rik van Riel <riel@surriel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* kasan: add atomic testsPaul Heidekrüger2024-02-221-0/+79
| | | | | | | | | | | | | | | | | | | | Test that KASan can detect some unsafe atomic accesses. As discussed in the linked thread below, these tests attempt to cover the most common uses of atomics and, therefore, aren't exhaustive. Link: https://lkml.kernel.org/r/20240202113259.3045705-1-paul.heidekrueger@tum.de Link: https://lore.kernel.org/all/20240131210041.686657-1-paul.heidekrueger@tum.de/T/#u Signed-off-by: Paul Heidekrüger <paul.heidekrueger@tum.de> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=214055 Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Marco Elver <elver@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: memcg: use larger batches for proactive reclaimT.J. Mercier2024-02-221-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before 388536ac291 ("mm:vmscan: fix inaccurate reclaim during proactive reclaim") we passed the number of pages for the reclaim request directly to try_to_free_mem_cgroup_pages, which could lead to significant overreclaim. After 0388536ac291 the number of pages was limited to a maximum 32 (SWAP_CLUSTER_MAX) to reduce the amount of overreclaim. However such a small batch size caused a regression in reclaim performance due to many more reclaim start/stop cycles inside memory_reclaim. The restart cost is amortized over more pages with larger batch sizes, and becomes a significant component of the runtime if the batch size is too small. Reclaim tries to balance nr_to_reclaim fidelity with fairness across nodes and cgroups over which the pages are spread. As such, the bigger the request, the bigger the absolute overreclaim error. Historic in-kernel users of reclaim have used fixed, small sized requests to approach an appropriate reclaim rate over time. When we reclaim a user request of arbitrary size, use decaying batch sizes to manage error while maintaining reasonable throughput. MGLRU enabled - memcg LRU used root - full reclaim pages/sec time (sec) pre-0388536ac291 : 68047 10.46 post-0388536ac291 : 13742 inf (reclaim-reclaimed)/4 : 67352 10.51 MGLRU enabled - memcg LRU not used /uid_0 - 1G reclaim pages/sec time (sec) overreclaim (MiB) pre-0388536ac291 : 258822 1.12 107.8 post-0388536ac291 : 105174 2.49 3.5 (reclaim-reclaimed)/4 : 233396 1.12 -7.4 MGLRU enabled - memcg LRU not used /uid_0 - full reclaim pages/sec time (sec) pre-0388536ac291 : 72334 7.09 post-0388536ac291 : 38105 14.45 (reclaim-reclaimed)/4 : 72914 6.96 [tjmercier@google.com: v4] Link: https://lkml.kernel.org/r/20240206175251.3364296-1-tjmercier@google.com Link: https://lkml.kernel.org/r/20240202233855.1236422-1-tjmercier@google.com Fixes: 0388536ac291 ("mm:vmscan: fix inaccurate reclaim during proactive reclaim") Signed-off-by: T.J. Mercier <tjmercier@google.com> Reviewed-by: Yosry Ahmed <yosryahmed@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Koutny <mkoutny@suse.com> Acked-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeelb@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Efly Young <yangyifei03@kuaishou.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/mmap: pass vma to vma_merge()Yajun Deng2024-02-221-14/+13
| | | | | | | | | | | | | | | These vma_merge() callers will pass mm, anon_vma and file, they all from the same vma. There is no need to pass three parameters at the same time. Pass vma instead of mm, anon_vma and file to vma_merge(), so that it can save two parameters. Link: https://lkml.kernel.org/r/20240203014632.2726545-1-yajun.deng@linux.dev Link: https://lore.kernel.org/lkml/20240125034922.1004671-2-yajun.deng@linux.dev/ Signed-off-by: Yajun Deng <yajun.deng@linux.dev> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Yajun Deng <yajun.deng@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/memory: ignore writable bit in folio_pte_batch()David Hildenbrand2024-02-221-6/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... and conditionally return to the caller if any PTE except the first one is writable. fork() has to make sure to properly write-protect in case any PTE is writable. Other users (e.g., page unmaping) are expected to not care. Link: https://lkml.kernel.org/r/20240129124649.189745-16-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alexghiti@rivosinc.com> Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: David S. Miller <davem@davemloft.net> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Russell King (Oracle) <linux@armlinux.org.uk> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/memory: ignore dirty/accessed/soft-dirty bits in folio_pte_batch()David Hildenbrand2024-02-221-5/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Let's always ignore the accessed/young bit: we'll always mark the PTE as old in our child process during fork, and upcoming users will similarly not care. Ignore the dirty bit only if we don't want to duplicate the dirty bit into the child process during fork. Maybe, we could just set all PTEs in the child dirty if any PTE is dirty. For now, let's keep the behavior unchanged, this can be optimized later if required. Ignore the soft-dirty bit only if the bit doesn't have any meaning in the src vma, and similarly won't have any in the copied dst vma. For now, we won't bother with the uffd-wp bit. Link: https://lkml.kernel.org/r/20240129124649.189745-15-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alexghiti@rivosinc.com> Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: David S. Miller <davem@davemloft.net> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Russell King (Oracle) <linux@armlinux.org.uk> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/memory: optimize fork() with PTE-mapped THPDavid Hildenbrand2024-02-221-19/+93
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Let's implement PTE batching when consecutive (present) PTEs map consecutive pages of the same large folio, and all other PTE bits besides the PFNs are equal. We will optimize folio_pte_batch() separately, to ignore selected PTE bits. This patch is based on work by Ryan Roberts. Use __always_inline for __copy_present_ptes() and keep the handling for single PTEs completely separate from the multi-PTE case: we really want the compiler to optimize for the single-PTE case with small folios, to not degrade performance. Note that PTE batching will never exceed a single page table and will always stay within VMA boundaries. Further, processing PTE-mapped THP that maybe pinned and have PageAnonExclusive set on at least one subpage should work as expected, but there is room for improvement: We will repeatedly (1) detect a PTE batch (2) detect that we have to copy a page (3) fall back and allocate a single page to copy a single page. For now we won't care as pinned pages are a corner case, and we should rather look into maintaining only a single PageAnonExclusive bit for large folios. Link: https://lkml.kernel.org/r/20240129124649.189745-14-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alexghiti@rivosinc.com> Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: David S. Miller <davem@davemloft.net> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Russell King (Oracle) <linux@armlinux.org.uk> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/memory: pass PTE to copy_present_pte()David Hildenbrand2024-02-221-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We already read it, let's just forward it. This patch is based on work by Ryan Roberts. [david@redhat.com: fix the hmm "exclusive_cow" selftest] Link: https://lkml.kernel.org/r/13f296b8-e882-47fd-b939-c2141dc28717@redhat.com Link: https://lkml.kernel.org/r/20240129124649.189745-13-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alexghiti@rivosinc.com> Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: David S. Miller <davem@davemloft.net> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Russell King (Oracle) <linux@armlinux.org.uk> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/memory: factor out copying the actual PTE in copy_present_pte()David Hildenbrand2024-02-221-30/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Let's prepare for further changes. Link: https://lkml.kernel.org/r/20240129124649.189745-12-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alexghiti@rivosinc.com> Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: David S. Miller <davem@davemloft.net> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Russell King (Oracle) <linux@armlinux.org.uk> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm/vmscan: change the type of file from int to boolHao Ge2024-02-221-2/+2
| | | | | | | | Change the type of file from int to bool because is_file_lru return bool Link: https://lkml.kernel.org/r/20240131103802.122920-1-gehao@kylinos.cn Signed-off-by: Hao Ge <gehao@kylinos.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* mm: compaction: update the cc->nr_migratepages when allocating or freeing ↵Baolin Wang2024-02-221-2/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | the freepages Currently we will use 'cc->nr_freepages >= cc->nr_migratepages' comparison to ensure that enough freepages are isolated in isolate_freepages(), however it just decreases the cc->nr_freepages without updating cc->nr_migratepages in compaction_alloc(), which will waste more CPU cycles and cause too many freepages to be isolated. So we should also update the cc->nr_migratepages when allocating or freeing the freepages to avoid isolating excess freepages. And I can see fewer free pages are scanned and isolated when running thpcompact on my Arm64 server: k6.7 k6.7_patched Ops Compaction pages isolated 120692036.00 118160797.00 Ops Compaction migrate scanned 131210329.00 154093268.00 Ops Compaction free scanned 1090587971.00 1080632536.00 Ops Compact scan efficiency 12.03 14.26 Moreover, I did not see an obvious latency improvements, this is likely because isolating freepages is not the bottleneck in the thpcompact test case. k6.7 k6.7_patched Amean fault-both-1 1089.76 ( 0.00%) 1080.16 * 0.88%* Amean fault-both-3 1616.48 ( 0.00%) 1636.65 * -1.25%* Amean fault-both-5 2266.66 ( 0.00%) 2219.20 * 2.09%* Amean fault-both-7 2909.84 ( 0.00%) 2801.90 * 3.71%* Amean fault-both-12 4861.26 ( 0.00%) 4733.25 * 2.63%* Amean fault-both-18 7351.11 ( 0.00%) 6950.51 * 5.45%* Amean fault-both-24 9059.30 ( 0.00%) 9159.99 * -1.11%* Amean fault-both-30 10685.68 ( 0.00%) 11399.02 * -6.68%* Link: https://lkml.kernel.org/r/6440493f18da82298152b6305d6b41c2962a3ce6.1708409245.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* userfaultfd: handle zeropage moves by UFFDIO_MOVESuren Baghdasaryan2024-02-222-51/+98
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Current implementation of UFFDIO_MOVE fails to move zeropages and returns EBUSY when it encounters one. We can handle them by mapping a zeropage at the destination and clearing the mapping at the source. This is done both for ordinary and for huge zeropages. Link: https://lkml.kernel.org/r/20240131175618.2417291-1-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reported-by: kernel test robot <lkp@intel.com> Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Closes: https://lore.kernel.org/r/202401300107.U8iMAkTl-lkp@intel.com/ Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Brian Geffon <bgeffon@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Nicolas Geoffray <ngeoffray@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: ZhangPeng <zhangpeng362@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
generated by cgit v1.2.3 (git 2.25.1) at 2025-02-28 04:03:25 +0000