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* [PATCH] Prepare for __copy_from_user_inatomic to not zero missed bytesNeilBrown2006-06-252-14/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The problem is that when we write to a file, the copy from userspace to pagecache is first done with preemption disabled, so if the source address is not immediately available the copy fails *and* *zeros* *the* *destination*. This is a problem because a concurrent read (which admittedly is an odd thing to do) might see zeros rather that was there before the write, or what was there after, or some mixture of the two (any of these being a reasonable thing to see). If the copy did fail, it will immediately be retried with preemption re-enabled so any transient problem with accessing the source won't cause an error. The first copying does not need to zero any uncopied bytes, and doing so causes the problem. It uses copy_from_user_atomic rather than copy_from_user so the simple expedient is to change copy_from_user_atomic to *not* zero out bytes on failure. The first of these two patches prepares for the change by fixing two places which assume copy_from_user_atomic does zero the tail. The two usages are very similar pieces of code which copy from a userspace iovec into one or more page-cache pages. These are changed to remove the assumption. The second patch changes __copy_from_user_inatomic* to not zero the tail. Once these are accepted, I will look at similar patches of other architectures where this is important (ppc, mips and sparc being the ones I can find). This patch: There is a problem with __copy_from_user_inatomic zeroing the tail of the buffer in the case of an error. As it is called in atomic context, the error may be transient, so it results in zeros being written where maybe they shouldn't be. In the usage in filemap, this opens a window for a well timed read to see data (zeros) which is not consistent with any ordering of reads and writes. Most cases where __copy_from_user_inatomic is called, a failure results in __copy_from_user being called immediately. As long as the latter zeros the tail, the former doesn't need to. However in *copy_from_user_iovec implementations (in both filemap and ntfs/file), it is assumed that copy_from_user_inatomic will zero the tail. This patch removes that assumption, so that after this patch it will be safe for copy_from_user_inatomic to not zero the tail. This patch also adds some commentary to filemap.h and asm-i386/uaccess.h. After this patch, all architectures that might disable preempt when kmap_atomic is called need to have their __copy_from_user_inatomic* "fixed". This includes - powerpc - i386 - mips - sparc Signed-off-by: Neil Brown <neilb@suse.de> Cc: David Howells <dhowells@redhat.com> Cc: Anton Altaparmakov <aia21@cantab.net> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] cpuset: remove extra cpuset_zone_allowed check in __alloc_pagesChris Wright2006-06-251-2/+1
| | | | | | | | | | This is redundant with check in wakeup_kswapd. Signed-off-by: Chris Wright <chrisw@sous-sol.org> Acked-by: Paul Jackson <pj@sgi.com> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] pdflush: handle resume wakeupsAndrew Morton2006-06-251-8/+7
| | | | | | | | | | | | | | | | | | pdflush is carefully designed to ensure that all wakeups have some corresponding work to do - if a woken-up pdflush thread discovers that it hasn't been given any work to do then this is considered an error. That all broke when swsusp came along - because a timer-delivered wakeup to a frozen pdflush thread will just get lost. This causes the pdflush thread to get lost as well: the writeback timer is supposed to be re-armed by pdflush in process context, but pdflush doesn't execute the callout which does this. Fix that up by ignoring the return value from try_to_freeze(): jsut proceed, see if we have any work pending and only go back to sleep if that is not the case. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Allow migration of mlocked pagesChristoph Lameter2006-06-252-11/+8
| | | | | | | | | | | | | Hugh clarified the role of VM_LOCKED. So we can now implement page migration for mlocked pages. Allow the migration of mlocked pages. This means that try_to_unmap must unmap mlocked pages in the migration case. Signed-off-by: Christoph Lameter <clameter@sgi.com> Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] page migration: Support a vma migration functionChristoph Lameter2006-06-252-1/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Hooks for calling vma specific migration functions With this patch a vma may define a vma->vm_ops->migrate function. That function may perform page migration on its own (some vmas may not contain page structs and therefore cannot be handled by regular page migration. Pages in a vma may require special preparatory treatment before migration is possible etc) . Only mmap_sem is held when the migration function is called. The migrate() function gets passed two sets of nodemasks describing the source and the target of the migration. The flags parameter either contains MPOL_MF_MOVE which means that only pages used exclusively by the specified mm should be moved or MPOL_MF_MOVE_ALL which means that pages shared with other processes should also be moved. The migration function returns 0 on success or an error condition. An error condition will prevent regular page migration from occurring. On its own this patch cannot be included since there are no users for this functionality. But it seems that the uncached allocator will need this functionality at some point. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] AOP_TRUNCATED_PAGE victims in read_pages() belong in the LRUZach Brown2006-06-251-8/+5
| | | | | | | | | | | | | | | | | | | | | | | | AOP_TRUNCATED_PAGE victims in read_pages() belong in the LRU Nick Piggin rightly pointed out that the introduction of AOP_TRUNCATED_PAGE to read_pages() was wrong to leave A_T_P victim pages in the page cache but not put them in the LRU. Failing to do so hid them from the VM. A_T_P just means that the aop method unlocked the page rather than performing IO. It would be very rare that the page was truncated between the unlock and testing A_T_P. So we leave the pages in the LRU for likely reuse soon rather than backing them back out of the page cache. We do this by matching the behaviour before the A_T_P introduction which added pages to the LRU regardless of what ->readpage() did. This doesn't include the unrelated cleanup in Nick's initial fix which changed read_pages() to return void to match its only caller's behaviour of ignoring errors. Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Zach Brown <zach.brown@oracle.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Kill PF_SYNCWRITE flagJens Axboe2006-06-231-3/+0
| | | | | | | | | | | | | | | A process flag to indicate whether we are doing sync io is incredibly ugly. It also causes performance problems when one does a lot of async io and then proceeds to sync it. Part of the io will go out as async, and the other part as sync. This causes a disconnect between the previously submitted io and the synced io. For io schedulers such as CFQ, this will cause us lost merges and suboptimal behaviour in scheduling. Remove PF_SYNCWRITE completely from the fsync/msync paths, and let the O_DIRECT path just directly indicate that the writes are sync by using WRITE_SYNC instead. Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] More BUG_ON conversionEric Sesterhenn2006-06-231-2/+1
| | | | | | | | | | | Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: James Bottomley <James.Bottomley@steeleye.com> Acked-by: "Salyzyn, Mark" <mark_salyzyn@adaptec.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Remove semi-softlockup from invalidate_mapping_pagesNeilBrown2006-06-231-6/+16
| | | | | | | | | | | | | | | | | | | | | If invalidate_mapping_pages is called to invalidate a very large mapping (e.g. a very large block device) and if the only active page in that device is near the end (or at least, at a very large index), such as, say, the superblock of an md array, and if that page happens to be locked when invalidate_mapping_pages is called, then pagevec_lookup will return this page and as it is locked, 'next' will be incremented and pagevec_lookup will be called again. and again. and again. while we count from 0 upto a very large number. We should really always set 'next' to 'page->index+1' before going around the loop again, not just if the page isn't locked. Cc: "Steinar H. Gunderson" <sgunderson@bigfoot.com> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] percpu_counters: create lib/percpu_counter.cRavikiran G Thirumalai2006-06-231-42/+0
| | | | | | | | - Move percpu_counter routines from mm/swap.c to lib/percpu_counter.c Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] read_mapping_page for address spacePekka Enberg2006-06-231-2/+1
| | | | | | | | | | Add read_mapping_page() which is used for callers that pass mapping->a_ops->readpage as the filler for read_cache_page. This removes some duplication from filesystem code. Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] x86: cache pollution aware __copy_from_user_ll()Hiro Yoshioka2006-06-232-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use the x86 cache-bypassing copy instructions for copy_from_user(). Some performance data are Total of GLOBAL_POWER_EVENTS (CPU cycle samples) 2.6.12.4.orig 1921587 2.6.12.4.nt 1599424 1599424/1921587=83.23% (16.77% reduction) BSQ_CACHE_REFERENCE (L3 cache miss) 2.6.12.4.orig 57427 2.6.12.4.nt 20858 20858/57427=36.32% (63.7% reduction) L3 cache miss reduction of __copy_from_user_ll samples % 37408 65.1412 vmlinux __copy_from_user_ll 23 0.1103 vmlinux __copy_user_zeroing_intel_nocache 23/37408=0.061% (99.94% reduction) Top 5 of 2.6.12.4.nt Counted GLOBAL_POWER_EVENTS events (time during which processor is not stopped) with a unit mask of 0x01 (mandatory) count 100000 samples % app name symbol name 128392 8.0274 vmlinux __copy_user_zeroing_intel_nocache 64206 4.0143 vmlinux journal_add_journal_head 59746 3.7355 vmlinux do_get_write_access 47674 2.9807 vmlinux journal_put_journal_head 46021 2.8774 vmlinux journal_dirty_metadata pattern9-0-cpu4-0-09011728/summary.out Counted BSQ_CACHE_REFERENCE events (cache references seen by the bus unit) with a unit mask of 0x3f (multiple flags) count 3000 samples % app name symbol name 69755 4.2861 vmlinux __copy_user_zeroing_intel_nocache 55685 3.4215 vmlinux journal_add_journal_head 52371 3.2179 vmlinux __find_get_block 45504 2.7960 vmlinux journal_put_journal_head 36005 2.2123 vmlinux journal_stop pattern9-0-cpu4-0-09011744/summary.out Counted BSQ_CACHE_REFERENCE events (cache references seen by the bus unit) with a unit mask of 0x200 (read 3rd level cache miss) count 3000 samples % app name symbol name 1147 5.4994 vmlinux journal_add_journal_head 881 4.2240 vmlinux journal_dirty_data 872 4.1809 vmlinux blk_rq_map_sg 734 3.5192 vmlinux journal_commit_transaction 617 2.9582 vmlinux radix_tree_delete pattern9-0-cpu4-0-09011731/summary.out iozone results are original 2.6.12.4 CPU time = 207.768 sec cache aware CPU time = 184.783 sec (three times run) 184.783/207.768=88.94% (11.06% reduction) original: pattern9-0-cpu4-0-08191720/iozone.out: CPU Utilization: Wall time 45.997 CPU time 64.527 CPU utilization 140.28 % pattern9-0-cpu4-0-08191741/iozone.out: CPU Utilization: Wall time 46.878 CPU time 71.933 CPU utilization 153.45 % pattern9-0-cpu4-0-08191743/iozone.out: CPU Utilization: Wall time 45.152 CPU time 71.308 CPU utilization 157.93 % cache awre: pattern9-0-cpu4-0-09011728/iozone.out: CPU Utilization: Wall time 44.842 CPU time 62.465 CPU utilization 139.30 % pattern9-0-cpu4-0-09011731/iozone.out: CPU Utilization: Wall time 44.718 CPU time 59.273 CPU utilization 132.55 % pattern9-0-cpu4-0-09011744/iozone.out: CPU Utilization: Wall time 44.367 CPU time 63.045 CPU utilization 142.10 % Signed-off-by: Hiro Yoshioka <hyoshiok@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] SELinux: add security_task_movememory calls to mm codeDavid Quigley2006-06-232-0/+11
| | | | | | | | | | | | | | | | | This patch inserts security_task_movememory hook calls into memory management code to enable security modules to mediate this operation between tasks. Since the last posting, the hook has been renamed following feedback from Christoph Lameter. Signed-off-by: David Quigley <dpquigl@tycho.nsa.gov> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: James Morris <jmorris@namei.org> Cc: Andi Kleen <ak@muc.de> Acked-by: Christoph Lameter <clameter@sgi.com> Acked-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] page migration: sys_move_pages(): support moving of individual pagesChristoph Lameter2006-06-232-6/+266
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | move_pages() is used to move individual pages of a process. The function can be used to determine the location of pages and to move them onto the desired node. move_pages() returns status information for each page. long move_pages(pid, number_of_pages_to_move, addresses_of_pages[], nodes[] or NULL, status[], flags); The addresses of pages is an array of void * pointing to the pages to be moved. The nodes array contains the node numbers that the pages should be moved to. If a NULL is passed instead of an array then no pages are moved but the status array is updated. The status request may be used to determine the page state before issuing another move_pages() to move pages. The status array will contain the state of all individual page migration attempts when the function terminates. The status array is only valid if move_pages() completed successfullly. Possible page states in status[]: 0..MAX_NUMNODES The page is now on the indicated node. -ENOENT Page is not present -EACCES Page is mapped by multiple processes and can only be moved if MPOL_MF_MOVE_ALL is specified. -EPERM The page has been mlocked by a process/driver and cannot be moved. -EBUSY Page is busy and cannot be moved. Try again later. -EFAULT Invalid address (no VMA or zero page). -ENOMEM Unable to allocate memory on target node. -EIO Unable to write back page. The page must be written back in order to move it since the page is dirty and the filesystem does not provide a migration function that would allow the moving of dirty pages. -EINVAL A dirty page cannot be moved. The filesystem does not provide a migration function and has no ability to write back pages. The flags parameter indicates what types of pages to move: MPOL_MF_MOVE Move pages that are only mapped by the process. MPOL_MF_MOVE_ALL Also move pages that are mapped by multiple processes. Requires sufficient capabilities. Possible return codes from move_pages() -ENOENT No pages found that would require moving. All pages are either already on the target node, not present, had an invalid address or could not be moved because they were mapped by multiple processes. -EINVAL Flags other than MPOL_MF_MOVE(_ALL) specified or an attempt to migrate pages in a kernel thread. -EPERM MPOL_MF_MOVE_ALL specified without sufficient priviledges. or an attempt to move a process belonging to another user. -EACCES One of the target nodes is not allowed by the current cpuset. -ENODEV One of the target nodes is not online. -ESRCH Process does not exist. -E2BIG Too many pages to move. -ENOMEM Not enough memory to allocate control array. -EFAULT Parameters could not be accessed. A test program for move_pages() may be found with the patches on ftp.kernel.org:/pub/linux/kernel/people/christoph/pmig/patches-2.6.17-rc4-mm3 From: Christoph Lameter <clameter@sgi.com> Detailed results for sys_move_pages() Pass a pointer to an integer to get_new_page() that may be used to indicate where the completion status of a migration operation should be placed. This allows sys_move_pags() to report back exactly what happened to each page. Wish there would be a better way to do this. Looks a bit hacky. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Jes Sorensen <jes@trained-monkey.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Andi Kleen <ak@muc.de> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] page migration: use allocator function for migrate_pages()Christoph Lameter2006-06-232-85/+53
| | | | | | | | | | | | | | | | | Instead of passing a list of new pages, pass a function to allocate a new page. This allows the correct placement of MPOL_INTERLEAVE pages during page migration. It also further simplifies the callers of migrate pages. migrate_pages() becomes similar to migrate_pages_to() so drop migrate_pages_to(). The batching of new page allocations becomes unnecessary. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Jes Sorensen <jes@trained-monkey.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] page migration: handle freeing of pages in migrate_pages()Christoph Lameter2006-06-232-32/+24
| | | | | | | | | | | | | | | Do not leave pages on the lists passed to migrate_pages(). Seems that we will not need any postprocessing of pages. This will simplify the handling of pages by the callers of migrate_pages(). Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Jes Sorensen <jes@trained-monkey.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] page migration: simplify migrate_pages()Christoph Lameter2006-06-231-103/+115
| | | | | | | | | | | | | | | | | | | | | | Currently migrate_pages() is mess with lots of goto. Extract two functions from migrate_pages() and get rid of the gotos. Plus we can just unconditionally set the locked bit on the new page since we are the only one holding a reference. Locking is to stop others from accessing the page once we establish references to the new page. Remove the list_del from move_to_lru in order to have finer control over list processing. [akpm@osdl.org: add debug check] Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Jes Sorensen <jes@trained-monkey.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] printk() should not be called under zone->lockKirill Korotaev2006-06-231-4/+5
| | | | | | | | | | | | | | This patch fixes printk() under zone->lock in show_free_areas(). It can be unsafe to call printk() under this lock, since caller can try to allocate/free some memory and selfdeadlock on this lock. I found allocations/freeing mem both in netconsole and serial console. This issue was faced in reallity when meminfo was periodically printed for debug purposes and netconsole was used. Signed-off-by: Kirill Korotaev <dev@openvz.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kernel-doc for mm/filemap.cRandy Dunlap2006-06-231-53/+120
| | | | | | | | | | | mm/filemap.c: - add lots of kernel-doc; - fix some typos and kernel-doc errors; - drop some blank lines between function close and EXPORT_SYMBOL(); Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] slab: kmalloc, kzalloc comments cleanup and fixPaul Drynoff2006-06-231-18/+2
| | | | | | | | | | | | | | | | | | - Move comments for kmalloc to right place, currently it near __do_kmalloc - Comments for kzalloc - More detailed comments for kmalloc - Appearance of "kmalloc" and "kzalloc" man pages after "make mandocs" [rdunlap@xenotime.net: simplification] Signed-off-by: Paul Drynoff <pauldrynoff@gmail.com> Acked-by: Randy Dunlap <rdunlap@xenotime.net> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] update vm_total_pages at memory hotaddKAMEZAWA Hiroyuki2006-06-231-1/+1
| | | | | | Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] initialise total_memory() earlierAndrew Morton2006-06-232-6/+5
| | | | | | | | | | | | | | | Initialise total_memory earlier in boot. Because if for some reason we run page reclaim early in boot, we don't want total_memory to be zero when we use it as a divisor. And rename total_memory to vm_total_pages to avoid naming clashes with architectures. Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Martin Bligh <mbligh@google.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mm/slab.c: fix early init assumptionIngo Molnar2006-06-231-2/+10
| | | | | | | | | | | | | | | | | | | | | | | The SLAB bootstrap code assumes that the first two kmalloc caches created (the INDEX_AC and INDEX_L3 kmalloc caches) wont be off-slab. But due to AC and L3 structure size increase in lockdep, one of them ended up being off-slab, and subsequently crashing with: Unable to handle kernel NULL pointer dereference at 0000000000000000 RIP: [<ffffffff80267478>] kmem_cache_alloc+0x26/0x7d The fix is to introduce a bootstrap flag and to use it to prevent off-slab caches being created so early during bootup. (The calculation for off-slab caches is quite complex so i didnt want to complicate things with introducing yet another INDEX_ calculation, the flag approach is simpler and smaller.) Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fix update_mmu_cache in fremap.cHugh Dickins2006-06-231-1/+8
| | | | | | | | | | | There are two calls to update_mmu_cache in fremap.c, both defective. The one in install_page needs to be accompanied by lazy_mmu_prot_update (some other cleanup time, move that into ia64 update_mmu_cache itself); and the one in install_file_pte should be removed since the pte is not present. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] swapoff: use atomic_inc_not_zero() on mm_usersHugh Dickins2006-06-231-3/+1
| | | | | | | | | | Now that we have atomic_inc_not_zero, it's more elegant for try_to_unuse to use that on mm_users: doesn't actually matter at present, but safer to be sure that once mm_users has gone to 0, nothing raises it for an instant. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] add page_mkwrite() vm_operations methodDavid Howells2006-06-233-28/+95
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a new VMA operation to notify a filesystem or other driver about the MMU generating a fault because userspace attempted to write to a page mapped through a read-only PTE. This facility permits the filesystem or driver to: (*) Implement storage allocation/reservation on attempted write, and so to deal with problems such as ENOSPC more gracefully (perhaps by generating SIGBUS). (*) Delay making the page writable until the contents have been written to a backing cache. This is useful for NFS/AFS when using FS-Cache/CacheFS. It permits the filesystem to have some guarantee about the state of the cache. (*) Account and limit number of dirty pages. This is one piece of the puzzle needed to make shared writable mapping work safely in FUSE. Needed by cachefs (Or is it cachefiles? Or fscache? <head spins>). At least four other groups have stated an interest in it or a desire to use the functionality it provides: FUSE, OCFS2, NTFS and JFFS2. Also, things like EXT3 really ought to use it to deal with the case of shared-writable mmap encountering ENOSPC before we permit the page to be dirtied. From: Peter Zijlstra <a.p.zijlstra@chello.nl> get_user_pages(.write=1, .force=1) can generate COW hits on read-only shared mappings, this patch traps those as mkpage_write candidates and fails to handle them the old way. Signed-off-by: David Howells <dhowells@redhat.com> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Joel Becker <Joel.Becker@oracle.com> Cc: Mark Fasheh <mark.fasheh@oracle.com> Cc: Anton Altaparmakov <aia21@cantab.net> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sparsemem: record nid during memory presentAndy Whitcroft2006-06-231-2/+20
| | | | | | | | | | | | | | | | Record the node id as we mark sections for instantiation. Use this nid during instantiation to direct allocations. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Cc: Mike Kravetz <kravetz@us.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Bob Picco <bob.picco@hp.com> Cc: Jack Steiner <steiner@sgi.com> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Martin Bligh <mbligh@google.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] slab: verify pointers before freePekka Enberg2006-06-231-9/+4
| | | | | | | | | | | | | | | | | | | | | | | | | Passing an invalid pointer to kfree() and kmem_cache_free() is likely to cause bad memory corruption or even take down the whole system because the bad pointer is likely reused immediately due to the per-CPU caches. Until now, we don't do any verification for this if CONFIG_DEBUG_SLAB is disabled. As suggested by Linus, add PageSlab check to page_to_cache() and page_to_slab() to verify pointers passed to kfree(). Also, move the stronger check from cache_free_debugcheck() to kmem_cache_free() to ensure the passed pointer actually belongs to the cache we're about to free the object. For page_to_cache() and page_to_slab(), the assertions should have virtually no extra cost (two instructions, no data cache pressure) and for kmem_cache_free() the overhead should be minimal. Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] More page migration: use migration entries for file pagesChristoph Lameter2006-06-233-28/+124
| | | | | | | | | | | | | | | | | This implements the use of migration entries to preserve ptes of file backed pages during migration. Processes can therefore be migrated back and forth without loosing their connection to pagecache pages. Note that we implement the migration entries only for linear mappings. Nonlinear mappings still require the unmapping of the ptes for migration. And another writepage() ugliness shows up. writepage() can drop the page lock. Therefore we have to remove migration ptes before calling writepages() in order to avoid having migration entries point to unlocked pages. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] More page migration: do not inc/dec rss countersChristoph Lameter2006-06-232-2/+1
| | | | | | | | | | | If we install a migration entry then the rss not really decreases since the page is just moved somewhere else. We can save ourselves the work of decrementing and later incrementing which will just eventually cause cacheline bouncing. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Swapless page migration: modify core logicChristoph Lameter2006-06-232-34/+23
| | | | | | | | | | | | | | | | | | | Use the migration entries for page migration This modifies the migration code to use the new migration entries. It now becomes possible to migrate anonymous pages without having to add a swap entry. We add a couple of new functions to replace migration entries with the proper ptes. We cannot take the tree_lock for migrating anonymous pages anymore. However, we know that we hold the only remaining reference to the page when the page count reaches 1. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Swapless page migration: rip out swap based logicChristoph Lameter2006-06-233-119/+3
| | | | | | | | | | | | | | | Rip the page migration logic out. Remove all code that has to do with swapping during page migration. This also guts the ability to migrate pages to swap. No one used that so lets let it go for good. Page migration should be a bit broken after this patch. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Swapless page migration: add R/W migration entriesChristoph Lameter2006-06-235-32/+195
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement read/write migration ptes We take the upper two swapfiles for the two types of migration ptes and define a series of macros in swapops.h. The VM is modified to handle the migration entries. migration entries can only be encountered when the page they are pointing to is locked. This limits the number of places one has to fix. We also check in copy_pte_range and in mprotect_pte_range() for migration ptes. We check for migration ptes in do_swap_cache and call a function that will then wait on the page lock. This allows us to effectively stop all accesses to apge. Migration entries are created by try_to_unmap if called for migration and removed by local functions in migrate.c From: Hugh Dickins <hugh@veritas.com> Several times while testing swapless page migration (I've no NUMA, just hacking it up to migrate recklessly while running load), I've hit the BUG_ON(!PageLocked(p)) in migration_entry_to_page. This comes from an orphaned migration entry, unrelated to the current correctly locked migration, but hit by remove_anon_migration_ptes as it checks an address in each vma of the anon_vma list. Such an orphan may be left behind if an earlier migration raced with fork: copy_one_pte can duplicate a migration entry from parent to child, after remove_anon_migration_ptes has checked the child vma, but before it has removed it from the parent vma. (If the process were later to fault on this orphaned entry, it would hit the same BUG from migration_entry_wait.) This could be fixed by locking anon_vma in copy_one_pte, but we'd rather not. There's no such problem with file pages, because vma_prio_tree_add adds child vma after parent vma, and the page table locking at each end is enough to serialize. Follow that example with anon_vma: add new vmas to the tail instead of the head. (There's no corresponding problem when inserting migration entries, because a missed pte will leave the page count and mapcount high, which is allowed for. And there's no corresponding problem when migrating via swap, because a leftover swap entry will be correctly faulted. But the swapless method has no refcounting of its entries.) From: Ingo Molnar <mingo@elte.hu> pte_unmap_unlock() takes the pte pointer as an argument. From: Hugh Dickins <hugh@veritas.com> Several times while testing swapless page migration, gcc has tried to exec a pointer instead of a string: smells like COW mappings are not being properly write-protected on fork. The protection in copy_one_pte looks very convincing, until at last you realize that the second arg to make_migration_entry is a boolean "write", and SWP_MIGRATION_READ is 30. Anyway, it's better done like in change_pte_range, using is_write_migration_entry and make_migration_entry_read. From: Hugh Dickins <hugh@veritas.com> Remove unnecessary obfuscation from sys_swapon's range check on swap type, which blew up causing memory corruption once swapless migration made MAX_SWAPFILES no longer 2 ^ MAX_SWAPFILES_SHIFT. Signed-off-by: Hugh Dickins <hugh@veritas.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Christoph Lameter <clameter@engr.sgi.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> From: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] page migration cleanup: move fallback handling into special functionChristoph Lameter2006-06-231-51/+39
| | | | | | | | | | Move the fallback code into a new fallback function and make the function behave like any other migration function. This requires retaking the lock if pageout() drops it. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] page migration cleanup: pass "mapping" to migration functionsChristoph Lameter2006-06-231-36/+34
| | | | | | | | | | | | | | | | | Change handling of address spaces. Pass a pointer to the address space in which the page is migrated to all migration function. This avoids repeatedly having to retrieve the address space pointer from the page and checking it for validity. The old page mapping will change once migration has gone to a certain step, so it is less confusing to have the pointer always available. Move the setting of the mapping and index for the new page into migrate_pages(). Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] page migration cleanup: extract try_to_unmap from migration functionsChristoph Lameter2006-06-231-45/+31
| | | | | | | | | | | | | | | | | | Extract try_to_unmap and rename remove_references -> move_mapping try_to_unmap() may significantly change the page state by for example setting the dirty bit. It is therefore best to unmap in migrate_pages() before calling any migration functions. migrate_page_remove_references() will then only move the new page in place of the old page in the mapping. Rename the function to migrate_page_move_mapping(). This allows us to get rid of the special unmapping for the fallback path. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] page migration cleanup: drop nr_refs in remove_references()Christoph Lameter2006-06-231-10/+11
| | | | | | | | | | | | | | | | | | | Drop nr_refs parameter from migrate_page_remove_references() The nr_refs parameter is not really useful since the number of remaining references is always 1 for anonymous pages without a mapping 2 for pages with a mapping 3 for pages with a mapping and PagePrivate set. Remove the early check for the number of references since we are checking page_mapcount() earlier. Ultimately only the refcount matters after the tree_lock has been obtained. Signed-off-by: Christoph Lameter <clameter@sgi.coim> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] page migration cleanup: remove useless definitionsChristoph Lameter2006-06-231-4/+2
| | | | | | | | | | | Remove the export for migrate_page_remove_references() and migrate_page_copy() that are unlikely to be used directly by filesystems implementing migration. The export was useful when buffer_migrate_page() lived in fs/buffer.c but it has now been moved to migrate.c in the migration reorg. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] page migration cleanup: group functionsChristoph Lameter2006-06-231-70/+72
| | | | | | | | | Reorder functions in migrate.c. Group all migration functions for struct address_space_operations together. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] page migration cleanup: rename "ignrefs" to "migration"Christoph Lameter2006-06-231-9/+9
| | | | | | | | migrate is a better name since it is only used by page migration. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] writeback: fix range handlingOGAWA Hirofumi2006-06-233-3/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a writeback_control's `start' and `end' fields are used to indicate a one-byte-range starting at file offset zero, the required values of .start=0,.end=0 mean that the ->writepages() implementation has no way of telling that it is being asked to perform a range request. Because we're currently overloading (start == 0 && end == 0) to mean "this is not a write-a-range request". To make all this sane, the patch changes range of writeback_control. So caller does: If it is calling ->writepages() to write pages, it sets range (range_start/end or range_cyclic) always. And if range_cyclic is true, ->writepages() thinks the range is cyclic, otherwise it just uses range_start and range_end. This patch does, - Add LLONG_MAX, LLONG_MIN, ULLONG_MAX to include/linux/kernel.h -1 is usually ok for range_end (type is long long). But, if someone did, range_end += val; range_end is "val - 1" u64val = range_end >> bits; u64val is "~(0ULL)" or something, they are wrong. So, this adds LLONG_MAX to avoid nasty things, and uses LLONG_MAX for range_end. - All callers of ->writepages() sets range_start/end or range_cyclic. - Fix updates of ->writeback_index. It seems already bit strange. If it starts at 0 and ended by check of nr_to_write, this last index may reduce chance to scan end of file. So, this updates ->writeback_index only if range_cyclic is true or whole-file is scanned. Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Nathan Scott <nathans@sgi.com> Cc: Anton Altaparmakov <aia21@cantab.net> Cc: Steven French <sfrench@us.ibm.com> Cc: "Vladimir V. Saveliev" <vs@namesys.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] slab: redzone double-free detectionPekka Enberg2006-06-231-9/+23
| | | | | | | | | | | | | | | | At present our slab debugging tells us that it detected a double-free or corruption - it does not distinguish between them. Sometimes it's useful to be able to differentiate between these two types of information. Add double-free detection to redzone verification when freeing an object. As explained by Manfred, when we are freeing an object, both redzones should be RED_ACTIVE. However, if both are RED_INACTIVE, we are trying to free an object that was already free'd. Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] likely cleanup: remove unlikely in sys_mprotect()Hua Zhong2006-06-231-2/+1
| | | | | | | | | With likely/unlikely profiling on my not-so-busy-typical-developmentsystem there are 5k misses vs 2k hits. So I guess we should remove the unlikely. Signed-off-by: Hua Zhong <hzhong@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mm: introduce remap_vmalloc_range()Nick Piggin2006-06-231-2/+120
| | | | | | | | | Add remap_vmalloc_range, vmalloc_user, and vmalloc_32_user so that drivers can have a nice interface for remapping vmalloc memory. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] swsusp: rework memory shrinkerRafael J. Wysocki2006-06-231-55/+164
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rework the swsusp's memory shrinker in the following way: - Simplify balance_pgdat() by removing all of the swsusp-related code from it. - Make shrink_all_memory() use shrink_slab() and a new function shrink_all_zones() which calls shrink_active_list() and shrink_inactive_list() directly for each zone in a way that's optimized for suspend. In shrink_all_memory() we try to free exactly as many pages as the caller asks for, preferably in one shot, starting from easier targets.  If slab caches are huge, they are most likely to have enough pages to reclaim.  The inactive lists are next (the zones with more inactive pages go first) etc. Each time shrink_all_memory() attempts to shrink the active and inactive lists for each zone in 5 passes.  In the first pass, only the inactive lists are taken into consideration.  In the next two passes the active lists are also shrunk, but mapped pages are not reclaimed.  In the last two passes the active and inactive lists are shrunk and mapped pages are reclaimed as well. The aim of this is to alter the reclaim logic to choose the best pages to keep on resume and improve the responsiveness of the resumed system. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Con Kolivas <kernel@kolivas.org> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] slab: stop using list_for_eachChristoph Hellwig2006-06-231-27/+11
| | | | | | | | Use the _entry variant everywhere to clean the code up a tiny bit. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] slab: clean up kmem_getpagesChristoph Hellwig2006-06-231-16/+14
| | | | | | | | | | | | | | The last ifdef addition hit the ugliness treshold on this functions, so: - rename the variable i to nr_pages so it's somewhat descriptive - remove the addr variable and do the page_address call at the very end - instead of ifdef'ing the whole alloc_pages_node call just make the __GFP_COMP addition to flags conditional - rewrite the __GFP_COMP comment to make sense Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] tightening hugetlb strict accountingChen, Kenneth W2006-06-231-120/+162
| | | | | | | | | | | | | | | | | | | | | Current hugetlb strict accounting for shared mapping always assume mapping starts at zero file offset and reserves pages between zero and size of the file. This assumption often reserves (or lock down) a lot more pages then necessary if application maps at none zero file offset. libhugetlbfs is one example that requires proper reservation on shared mapping starts at none zero offset. This patch extends the reservation and hugetlb strict accounting to support any arbitrary pair of (offset, len), resulting a much more robust and accurate scheme. More importantly, it won't lock down any hugetlb pages outside file mapping. Signed-off-by: Ken Chen <kenneth.w.chen@intel.com> Acked-by: Adam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mm: fix typos in comments in mm/oom_kill.cDave Peterson2006-06-231-3/+3
| | | | | | | | This fixes a few typos in the comments in mm/oom_kill.c. Signed-off-by: David S. Peterson <dsp@llnl.gov> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] support for panic at OOMKAMEZAWA Hiroyuki2006-06-231-0/+3
| | | | | | | | | | | | | | | | | This patch adds panic_on_oom sysctl under sys.vm. When sysctl vm.panic_on_oom = 1, the kernel panics intead of killing rogue processes. And if vm.panic_on_oom is 0 the kernel will do oom_kill() in the same way as it does today. Of course, the default value is 0 and only root can modifies it. In general, oom_killer works well and kill rogue processes. So the whole system can survive. But there are environments where panic is preferable rather than kill some processes. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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