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* mm: use new return type vm_fault_tSouptick Joarder2018-06-071-4/+4
| | | | | | | | | | | | | | | | | | | | | Use new return type vm_fault_t for fault handler in struct vm_operations_struct. For now, this is just documenting that the function returns a VM_FAULT value rather than an errno. Once all instances are converted, vm_fault_t will become a distinct type. Link: http://lkml.kernel.org/r/20180511190542.GA2412@jordon-HP-15-Notebook-PC Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: Pavel Tatashin <pasha.tatashin@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/filemap.c: fix NULL pointer in page_cache_tree_insert()Matthew Wilcox2018-04-201-5/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | f2fs specifies the __GFP_ZERO flag for allocating some of its pages. Unfortunately, the page cache also uses the mapping's GFP flags for allocating radix tree nodes. It always masked off the __GFP_HIGHMEM flag, and masks off __GFP_ZERO in some paths, but not all. That causes radix tree nodes to be allocated with a NULL list_head, which causes backtraces like: __list_del_entry+0x30/0xd0 list_lru_del+0xac/0x1ac page_cache_tree_insert+0xd8/0x110 The __GFP_DMA and __GFP_DMA32 flags would also be able to sneak through if they are ever used. Fix them all by using GFP_RECLAIM_MASK at the innermost location, and remove it from earlier in the callchain. Link: http://lkml.kernel.org/r/20180411060320.14458-2-willy@infradead.org Fixes: 449dd6984d0e ("mm: keep page cache radix tree nodes in check") Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Reported-by: Chris Fries <cfries@google.com> Debugged-by: Minchan Kim <minchan@kernel.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/filemap.c: provide dummy filemap_page_mkwrite() for NOMMUArnd Bergmann2018-04-131-1/+5
| | | | | | | | | | | | | | | | | | | | | | | Building orangefs on MMU-less machines now results in a link error because of the newly introduced use of the filemap_page_mkwrite() function: ERROR: "filemap_page_mkwrite" [fs/orangefs/orangefs.ko] undefined! This adds a dummy version for it, similar to the existing generic_file_mmap and generic_file_readonly_mmap stubs in the same file, to avoid the link error without adding #ifdefs in each file system that uses these. Link: http://lkml.kernel.org/r/20180409105555.2439976-1-arnd@arndb.de Fixes: a5135eeab2e5 ("orangefs: implement vm_ops->fault") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Martin Brandenburg <martin@omnibond.com> Cc: Mike Marshall <hubcap@omnibond.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* page cache: use xa_lockMatthew Wilcox2018-04-111-43/+41
| | | | | | | | | | | | | | | | | Remove the address_space ->tree_lock and use the xa_lock newly added to the radix_tree_root. Rename the address_space ->page_tree to ->i_pages, since we don't really care that it's a tree. [willy@infradead.org: fix nds32, fs/dax.c] Link: http://lkml.kernel.org/r/20180406145415.GB20605@bombadil.infradead.orgLink: http://lkml.kernel.org/r/20180313132639.17387-9-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Jeff Layton <jlayton@redhat.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/filemap.c: remove include of hardirq.hYang Shi2018-01-311-1/+0
| | | | | | | | | | | | in_atomic() has been moved to include/linux/preempt.h, and the filemap.c doesn't use in_atomic() directly at all, so it sounds unnecessary to include hardirq.h. Link: http://lkml.kernel.org/r/1509985319-38633-1-git-send-email-yang.s@alibaba-inc.com Signed-off-by: Yang Shi <yang.s@alibaba-inc.com> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'afs-next-20171113' of ↵Linus Torvalds2017-11-161-0/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull AFS updates from David Howells: "kAFS filesystem driver overhaul. The major points of the overhaul are: (1) Preliminary groundwork is laid for supporting network-namespacing of kAFS. The remainder of the namespacing work requires some way to pass namespace information to submounts triggered by an automount. This requires something like the mount overhaul that's in progress. (2) sockaddr_rxrpc is used in preference to in_addr for holding addresses internally and add support for talking to the YFS VL server. With this, kAFS can do everything over IPv6 as well as IPv4 if it's talking to servers that support it. (3) Callback handling is overhauled to be generally passive rather than active. 'Callbacks' are promises by the server to tell us about data and metadata changes. Callbacks are now checked when we next touch an inode rather than actively going and looking for it where possible. (4) File access permit caching is overhauled to store the caching information per-inode rather than per-directory, shared over subordinate files. Whilst older AFS servers only allow ACLs on directories (shared to the files in that directory), newer AFS servers break that restriction. To improve memory usage and to make it easier to do mass-key removal, permit combinations are cached and shared. (5) Cell database management is overhauled to allow lighter locks to be used and to make cell records autonomous state machines that look after getting their own DNS records and cleaning themselves up, in particular preventing races in acquiring and relinquishing the fscache token for the cell. (6) Volume caching is overhauled. The afs_vlocation record is got rid of to simplify things and the superblock is now keyed on the cell and the numeric volume ID only. The volume record is tied to a superblock and normal superblock management is used to mediate the lifetime of the volume fscache token. (7) File server record caching is overhauled to make server records independent of cells and volumes. A server can be in multiple cells (in such a case, the administrator must make sure that the VL services for all cells correctly reflect the volumes shared between those cells). Server records are now indexed using the UUID of the server rather than the address since a server can have multiple addresses. (8) File server rotation is overhauled to handle VMOVED, VBUSY (and similar), VOFFLINE and VNOVOL indications and to handle rotation both of servers and addresses of those servers. The rotation will also wait and retry if the server says it is busy. (9) Data writeback is overhauled. Each inode no longer stores a list of modified sections tagged with the key that authorised it in favour of noting the modified region of a page in page->private and storing a list of keys that made modifications in the inode. This simplifies things and allows other keys to be used to actually write to the server if a key that made a modification becomes useless. (10) Writable mmap() is implemented. This allows a kernel to be build entirely on AFS. Note that Pre AFS-3.4 servers are no longer supported, though this can be added back if necessary (AFS-3.4 was released in 1998)" * tag 'afs-next-20171113' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: (35 commits) afs: Protect call->state changes against signals afs: Trace page dirty/clean afs: Implement shared-writeable mmap afs: Get rid of the afs_writeback record afs: Introduce a file-private data record afs: Use a dynamic port if 7001 is in use afs: Fix directory read/modify race afs: Trace the sending of pages afs: Trace the initiation and completion of client calls afs: Fix documentation on # vs % prefix in mount source specification afs: Fix total-length calculation for multiple-page send afs: Only progress call state at end of Tx phase from rxrpc callback afs: Make use of the YFS service upgrade to fully support IPv6 afs: Overhaul volume and server record caching and fileserver rotation afs: Move server rotation code into its own file afs: Add an address list concept afs: Overhaul cell database management afs: Overhaul permit caching afs: Overhaul the callback handling afs: Rename struct afs_call server member to cm_server ...
| * afs: Get rid of the afs_writeback recordDavid Howells2017-11-131-0/+1
| | | | | | | | | | | | | | | | | | | | Get rid of the afs_writeback record that kAFS is using to match keys with writes made by that key. Instead, keep a list of keys that have a file open for writing and/or sync'ing and iterate through those. Signed-off-by: David Howells <dhowells@redhat.com>
* | mm: remove __GFP_COLDMel Gorman2017-11-151-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As the page free path makes no distinction between cache hot and cold pages, there is no real useful ordering of pages in the free list that allocation requests can take advantage of. Juding from the users of __GFP_COLD, it is likely that a number of them are the result of copying other sites instead of actually measuring the impact. Remove the __GFP_COLD parameter which simplifies a number of paths in the page allocator. This is potentially controversial but bear in mind that the size of the per-cpu pagelists versus modern cache sizes means that the whole per-cpu list can often fit in the L3 cache. Hence, there is only a potential benefit for microbenchmarks that alloc/free pages in a tight loop. It's even worse when THP is taken into account which has little or no chance of getting a cache-hot page as the per-cpu list is bypassed and the zeroing of multiple pages will thrash the cache anyway. The truncate microbenchmarks are not shown as this patch affects the allocation path and not the free path. A page fault microbenchmark was tested but it showed no sigificant difference which is not surprising given that the __GFP_COLD branches are a miniscule percentage of the fault path. Link: http://lkml.kernel.org/r/20171018075952.10627-9-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm, pagevec: remove cold parameter for pagevecsMel Gorman2017-11-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Every pagevec_init user claims the pages being released are hot even in cases where it is unlikely the pages are hot. As no one cares about the hotness of pages being released to the allocator, just ditch the parameter. No performance impact is expected as the overhead is marginal. The parameter is removed simply because it is a bit stupid to have a useless parameter copied everywhere. Link: http://lkml.kernel.org/r/20171018075952.10627-6-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm, truncate: do not check mapping for every page being truncatedMel Gorman2017-11-151-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | During truncation, the mapping has already been checked for shmem and dax so it's known that workingset_update_node is required. This patch avoids the checks on mapping for each page being truncated. In all other cases, a lookup helper is used to determine if workingset_update_node() needs to be called. The one danger is that the API is slightly harder to use as calling workingset_update_node directly without checking for dax or shmem mappings could lead to surprises. However, the API rarely needs to be used and hopefully the comment is enough to give people the hint. sparsetruncate (tiny) 4.14.0-rc4 4.14.0-rc4 oneirq-v1r1 pickhelper-v1r1 Min Time 141.00 ( 0.00%) 140.00 ( 0.71%) 1st-qrtle Time 142.00 ( 0.00%) 141.00 ( 0.70%) 2nd-qrtle Time 142.00 ( 0.00%) 142.00 ( 0.00%) 3rd-qrtle Time 143.00 ( 0.00%) 143.00 ( 0.00%) Max-90% Time 144.00 ( 0.00%) 144.00 ( 0.00%) Max-95% Time 147.00 ( 0.00%) 145.00 ( 1.36%) Max-99% Time 195.00 ( 0.00%) 191.00 ( 2.05%) Max Time 230.00 ( 0.00%) 205.00 ( 10.87%) Amean Time 144.37 ( 0.00%) 143.82 ( 0.38%) Stddev Time 10.44 ( 0.00%) 9.00 ( 13.74%) Coeff Time 7.23 ( 0.00%) 6.26 ( 13.41%) Best99%Amean Time 143.72 ( 0.00%) 143.34 ( 0.26%) Best95%Amean Time 142.37 ( 0.00%) 142.00 ( 0.26%) Best90%Amean Time 142.19 ( 0.00%) 141.85 ( 0.24%) Best75%Amean Time 141.92 ( 0.00%) 141.58 ( 0.24%) Best50%Amean Time 141.69 ( 0.00%) 141.31 ( 0.27%) Best25%Amean Time 141.38 ( 0.00%) 140.97 ( 0.29%) As you'd expect, the gain is marginal but it can be detected. The differences in bonnie are all within the noise which is not surprising given the impact on the microbenchmark. radix_tree_update_node_t is a callback for some radix operations that optionally passes in a private field. The only user of the callback is workingset_update_node and as it no longer requires a mapping, the private field is removed. Link: http://lkml.kernel.org/r/20171018075952.10627-3-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: batch radix tree operations when truncating pagesJan Kara2017-11-151-0/+83
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently we remove pages from the radix tree one by one. To speed up page cache truncation, lock several pages at once and free them in one go. This allows us to batch radix tree operations in a more efficient way and also save round-trips on mapping->tree_lock. As a result we gain about 20% speed improvement in page cache truncation. Data from a simple benchmark timing 10000 truncates of 1024 pages (on ext4 on ramdisk but the filesystem is barely visible in the profiles). The range shows 1% and 95% percentiles of the measured times: 4.14-rc2 4.14-rc2 + batched truncation 248-256 209-219 249-258 209-217 248-255 211-239 248-255 209-217 247-256 210-218 [jack@suse.cz: convert delete_from_page_cache_batch() to pagevec] Link: http://lkml.kernel.org/r/20171018111648.13714-1-jack@suse.cz [akpm@linux-foundation.org: move struct pagevec forward declaration to top-of-file] Link: http://lkml.kernel.org/r/20171010151937.26984-8-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Andi Kleen <ak@linux.intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: factor out checks and accounting from __delete_from_page_cache()Jan Kara2017-11-151-31/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move checks and accounting updates from __delete_from_page_cache() into a separate function. We will reuse it when batching page cache truncation operations. Link: http://lkml.kernel.org/r/20171010151937.26984-7-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Andi Kleen <ak@linux.intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: move clearing of page->mapping to page_cache_tree_delete()Jan Kara2017-11-151-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Clearing of page->mapping makes sense in page_cache_tree_delete() as well and it will help us with batching things this way. Link: http://lkml.kernel.org/r/20171010151937.26984-6-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Andi Kleen <ak@linux.intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: move accounting updates before page_cache_tree_delete()Jan Kara2017-11-151-24/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move updates of various counters before page_cache_tree_delete() call. It will be easier to batch things this way and there is no difference whether the counters get updated before or after removal from the radix tree. Link: http://lkml.kernel.org/r/20171010151937.26984-5-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Andi Kleen <ak@linux.intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: factor out page cache page freeing into a separate functionJan Kara2017-11-151-13/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Factor out page freeing from delete_from_page_cache() into a separate function. We will need to call the same when batching pagecache deletion operations. invalidate_complete_page2() and replace_page_cache_page() might want to call this function as well however they currently don't seem to handle THPs so it's unnecessary for them to take the hit of checking whether a page is THP or not. Link: http://lkml.kernel.org/r/20171010151937.26984-4-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Andi Kleen <ak@linux.intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: remove nr_pages argument from pagevec_lookup_{,range}_tag()Jan Kara2017-11-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | All users of pagevec_lookup() and pagevec_lookup_range() now pass PAGEVEC_SIZE as a desired number of pages. Just drop the argument. Link: http://lkml.kernel.org/r/20171009151359.31984-15-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: use pagevec_lookup_range_tag() in __filemap_fdatawait_range()Jan Kara2017-11-151-8/+6
| | | | | | | | | | | | | | | | | | | | | | | | Use pagevec_lookup_range_tag() in __filemap_fdatawait_range() as it is interested only in pages from given range. Remove unnecessary code resulting from this. Link: http://lkml.kernel.org/r/20171009151359.31984-11-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: implement find_get_pages_range_tag()Jan Kara2017-11-151-9/+24
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "Ranged pagevec tagged lookup", v3. In this series I provide a ranged variant of pagevec_lookup_tag() and use it in places where it makes sense. This series removes some common code and it also has a potential for speeding up some operations similarly as for pagevec_lookup_range() (but for now I can think of only artificial cases where this happens). This patch (of 16): Implement a variant of find_get_pages_tag() that stops iterating at given index. Lots of users of this function (through pagevec_lookup()) actually want a range lookup and all of them are currently open-coding this. Also create corresponding pagevec_lookup_range_tag() function. Link: http://lkml.kernel.org/r/20171009151359.31984-2-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Bob Peterson <rpeterso@redhat.com> Cc: Chao Yu <yuchao0@huawei.com> Cc: David Howells <dhowells@redhat.com> Cc: David Sterba <dsterba@suse.com> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Cc: Steve French <sfrench@samba.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: "Yan, Zheng" <zyan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: have filemap_check_and_advance_wb_err clear AS_EIO/AS_ENOSPCJeff Layton2017-10-031-0/+8
| | | | | | | | | | | | | | | | | | | | | | Eryu noticed that he could sometimes get a leftover error reported when it shouldn't be on fsync with ext2 and non-journalled ext4. The problem is that writeback_single_inode still uses filemap_fdatawait. That picks up a previously set AS_EIO flag, which would ordinarily have been cleared before. Since we're mostly using this function as a replacement for filemap_check_errors, have filemap_check_and_advance_wb_err clear AS_EIO and AS_ENOSPC when reporting an error. That should allow the new function to better emulate the behavior of the old with respect to these flags. Link: http://lkml.kernel.org/r/20170922133331.28812-1-jlayton@kernel.org Signed-off-by: Jeff Layton <jlayton@redhat.com> Reported-by: Eryu Guan <eguan@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: Fix page cache inconsistency when mixing buffered and AIO DIOLukas Czerner2017-09-251-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently when mixing buffered reads and asynchronous direct writes it is possible to end up with the situation where we have stale data in the page cache while the new data is already written to disk. This is permanent until the affected pages are flushed away. Despite the fact that mixing buffered and direct IO is ill-advised it does pose a thread for a data integrity, is unexpected and should be fixed. Fix this by deferring completion of asynchronous direct writes to a process context in the case that there are mapped pages to be found in the inode. Later before the completion in dio_complete() invalidate the pages in question. This ensures that after the completion the pages in the written area are either unmapped, or populated with up-to-date data. Also do the same for the iomap case which uses iomap_dio_complete() instead. This has a side effect of deferring the completion to a process context for every AIO DIO that happens on inode that has pages mapped. However since the consensus is that this is ill-advised practice the performance implication should not be a problem. This was based on proposal from Jeff Moyer, thanks! Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge branch 'work.read_write' of ↵Linus Torvalds2017-09-141-7/+17
|\ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull nowait read support from Al Viro: "Support IOCB_NOWAIT for buffered reads and block devices" * 'work.read_write' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: block_dev: support RFW_NOWAIT on block device nodes fs: support RWF_NOWAIT for buffered reads fs: support IOCB_NOWAIT in generic_file_buffered_read fs: pass iocb to do_generic_file_read
| * fs: support IOCB_NOWAIT in generic_file_buffered_readMilosz Tanski2017-09-041-0/+9
| | | | | | | | | | | | | | | | | | | | | | Allow generic_file_buffered_read to bail out early instead of waiting for the page lock or reading a page if IOCB_NOWAIT is specified. Signed-off-by: Milosz Tanski <milosz@adfin.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Acked-by: Sage Weil <sage@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * fs: pass iocb to do_generic_file_readChristoph Hellwig2017-09-041-7/+8
| | | | | | | | | | | | | | | | | | And rename it to the more descriptive generic_file_buffered_read while at it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | sched/wait: Introduce wakeup boomark in wake_up_page_bitTim Chen2017-09-141-1/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that we have added breaks in the wait queue scan and allow bookmark on scan position, we put this logic in the wake_up_page_bit function. We can have very long page wait list in large system where multiple pages share the same wait list. We break the wake up walk here to allow other cpus a chance to access the list, and not to disable the interrupts when traversing the list for too long. This reduces the interrupt and rescheduling latency, and excessive page wait queue lock hold time. [ v2: Remove bookmark_wake_function ] Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'akpm' (patches from Andrew)Linus Torvalds2017-09-061-28/+39
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge updates from Andrew Morton: - various misc bits - DAX updates - OCFS2 - most of MM * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (119 commits) mm,fork: introduce MADV_WIPEONFORK x86,mpx: make mpx depend on x86-64 to free up VMA flag mm: add /proc/pid/smaps_rollup mm: hugetlb: clear target sub-page last when clearing huge page mm: oom: let oom_reap_task and exit_mmap run concurrently swap: choose swap device according to numa node mm: replace TIF_MEMDIE checks by tsk_is_oom_victim mm, oom: do not rely on TIF_MEMDIE for memory reserves access z3fold: use per-cpu unbuddied lists mm, swap: don't use VMA based swap readahead if HDD is used as swap mm, swap: add sysfs interface for VMA based swap readahead mm, swap: VMA based swap readahead mm, swap: fix swap readahead marking mm, swap: add swap readahead hit statistics mm/vmalloc.c: don't reinvent the wheel but use existing llist API mm/vmstat.c: fix wrong comment selftests/memfd: add memfd_create hugetlbfs selftest mm/shmem: add hugetlbfs support to memfd_create() mm, devm_memremap_pages: use multi-order radix for ZONE_DEVICE lookups mm/vmalloc.c: halve the number of comparisons performed in pcpu_get_vm_areas() ...
| * | mm: use find_get_pages_range() in filemap_range_has_page()Jan Kara2017-09-061-7/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We want only pages from given range in filemap_range_has_page(), furthermore we want at most a single page. So use find_get_pages_range() instead of pagevec_lookup() and remove unnecessary code. Link: http://lkml.kernel.org/r/20170726114704.7626-10-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | mm: implement find_get_pages_range()Jan Kara2017-09-061-12/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement a variant of find_get_pages() that stops iterating at given index. This may be substantial performance gain if the mapping is sparse. See following commit for details. Furthermore lots of users of this function (through pagevec_lookup()) actually want a range lookup and all of them are currently open-coding this. Also create corresponding pagevec_lookup_range() function. Link: http://lkml.kernel.org/r/20170726114704.7626-4-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | mm: make pagevec_lookup() update indexJan Kara2017-09-061-3/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make pagevec_lookup() (and underlying find_get_pages()) update index to the next page where iteration should continue. Most callers want this and also pagevec_lookup_tag() already does this. Link: http://lkml.kernel.org/r/20170726114704.7626-3-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | dax: remove DAX code from page_cache_tree_insert()Ross Zwisler2017-09-061-11/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that we no longer insert struct page pointers in DAX radix trees we can remove the special casing for DAX in page_cache_tree_insert(). This also allows us to make dax_wake_mapping_entry_waiter() local to fs/dax.c, removing it from dax.h. Link: http://lkml.kernel.org/r/20170724170616.25810-5-ross.zwisler@linux.intel.com Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Suggested-by: Jan Kara <jack@suse.cz> Reviewed-by: Jan Kara <jack@suse.cz> Cc: "Darrick J. Wong" <darrick.wong@oracle.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | Merge tag 'wberr-v4.14-1' of ↵Linus Torvalds2017-09-061-33/+31
|\ \ \ | |/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux Pull writeback error handling updates from Jeff Layton: "This pile continues the work from last cycle on better tracking writeback errors. In v4.13 we added some basic errseq_t infrastructure and converted a few filesystems to use it. This set continues refining that infrastructure, adds documentation, and converts most of the other filesystems to use it. The main exception at this point is the NFS client" * tag 'wberr-v4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux: ecryptfs: convert to file_write_and_wait in ->fsync mm: remove optimizations based on i_size in mapping writeback waits fs: convert a pile of fsync routines to errseq_t based reporting gfs2: convert to errseq_t based writeback error reporting for fsync fs: convert sync_file_range to use errseq_t based error-tracking mm: add file_fdatawait_range and file_write_and_wait fuse: convert to errseq_t based error tracking for fsync mm: consolidate dax / non-dax checks for writeback Documentation: add some docs for errseq_t errseq: rename __errseq_set to errseq_set
| * | mm: remove optimizations based on i_size in mapping writeback waitsJeff Layton2017-08-011-29/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Marcelo added this i_size based optimization with a patch in 2004 (commitid is from the linux-history tree): commit 765dad09b4ac101a32d87af2bb793c3060497d3c Author: Marcelo Tosatti <marcelo.tosatti@cyclades.com> Date: Tue Sep 7 17:51:17 2004 -0700 small wait_on_page_writeback_range() optimization filemap_fdatawait() calls wait_on_page_writeback_range() with -1 as "end" parameter. This is not needed since we know the EOF from the inode. Use that instead. There may be races here, particularly with clustered or network filesystems. It also seems like a bit of a layering violation since we're operating on an address_space here, not an inode. Finally, it's also questionable whether this optimization really helps on workloads that we care about. Should we be optimizing for writeback vs. truncate races in a codepath where we expect to wait anyway? It doesn't seem worth the risk. Remove this optimization from the filemap_fdatawait codepaths. This means that filemap_fdatawait becomes a trivial wrapper around filemap_fdatawait_range. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jeff Layton <jlayton@redhat.com>
| * | mm: add file_fdatawait_range and file_write_and_waitJeff Layton2017-07-311-0/+23
| | | | | | | | | | | | | | | | | | | | | | | | Necessary now for gfs2_fsync and sync_file_range, but there will eventually be other callers. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jeff Layton <jlayton@redhat.com>
| * | mm: consolidate dax / non-dax checks for writebackJeff Layton2017-07-291-6/+9
| | | | | | | | | | | | | | | | | | | | | | | | We have this complex conditional copied to several places. Turn it into a helper function. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jeff Layton <jlayton@redhat.com>
| * | errseq: rename __errseq_set to errseq_setJeff Layton2017-07-261-1/+1
| | | | | | | | | | | | | | | | | | | | | Nothing calls this wrapper anymore, so just remove it and rename the old function to get rid of the double underscore prefix. Signed-off-by: Jeff Layton <jlayton@redhat.com>
* | | page waitqueue: always add new entries at the endLinus Torvalds2017-08-281-1/+1
| |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 3510ca20ece0 ("Minor page waitqueue cleanups") made the page queue code always add new waiters to the back of the queue, which helps upcoming patches to batch the wakeups for some horrid loads where the wait queues grow to thousands of entries. However, I forgot about the nasrt add_page_wait_queue() special case code that is only used by the cachefiles code. That one still continued to add the new wait queue entries at the beginning of the list. Fix it, because any sane batched wakeup will require that we don't suddenly start getting new entries at the beginning of the list that we already handled in a previous batch. [ The current code always does the whole list while holding the lock, so wait queue ordering doesn't matter for correctness, but even then it's better to add later entries at the end from a fairness standpoint ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Avoid page waitqueue race leaving possible page locker waitingLinus Torvalds2017-08-271-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The "lock_page_killable()" function waits for exclusive access to the page lock bit using the WQ_FLAG_EXCLUSIVE bit in the waitqueue entry set. That means that if it gets woken up, other waiters may have been skipped. That, in turn, means that if it sees the page being unlocked, it *must* take that lock and return success, even if a lethal signal is also pending. So instead of checking for lethal signals first, we need to check for them after we've checked the actual bit that we were waiting for. Even if that might then delay the killing of the process. This matches the order of the old "wait_on_bit_lock()" infrastructure that the page locking used to use (and is still used in a few other areas). Note that if we still return an error after having unsuccessfully tried to acquire the page lock, that is ok: that means that some other thread was able to get ahead of us and lock the page, and when that other thread then unlocks the page, the wakeup event will be repeated. So any other pending waiters will now get properly woken up. Fixes: 62906027091f ("mm: add PageWaiters indicating tasks are waiting for a page bit") Cc: Nick Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Kara <jack@suse.cz> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Andi Kleen <ak@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Minor page waitqueue cleanupsLinus Torvalds2017-08-271-5/+6
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Tim Chen and Kan Liang have been battling a customer load that shows extremely long page wakeup lists. The cause seems to be constant NUMA migration of a hot page that is shared across a lot of threads, but the actual root cause for the exact behavior has not been found. Tim has a patch that batches the wait list traversal at wakeup time, so that we at least don't get long uninterruptible cases where we traverse and wake up thousands of processes and get nasty latency spikes. That is likely 4.14 material, but we're still discussing the page waitqueue specific parts of it. In the meantime, I've tried to look at making the page wait queues less expensive, and failing miserably. If you have thousands of threads waiting for the same page, it will be painful. We'll need to try to figure out the NUMA balancing issue some day, in addition to avoiding the excessive spinlock hold times. That said, having tried to rewrite the page wait queues, I can at least fix up some of the braindamage in the current situation. In particular: (a) we don't want to continue walking the page wait list if the bit we're waiting for already got set again (which seems to be one of the patterns of the bad load). That makes no progress and just causes pointless cache pollution chasing the pointers. (b) we don't want to put the non-locking waiters always on the front of the queue, and the locking waiters always on the back. Not only is that unfair, it means that we wake up thousands of reading threads that will just end up being blocked by the writer later anyway. Also add a comment about the layout of 'struct wait_page_key' - there is an external user of it in the cachefiles code that means that it has to match the layout of 'struct wait_bit_key' in the two first members. It so happens to match, because 'struct page *' and 'unsigned long *' end up having the same values simply because the page flags are the first member in struct page. Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Christopher Lameter <cl@linux.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: hugetlb: return immediately for hugetlb page in __delete_from_page_cache()Naoya Horiguchi2017-07-101-3/+5
| | | | | | | | | | | | | | | | We avoid calling __mod_node_page_state(NR_FILE_PAGES) for hugetlb page now, but it's not enough because later code doesn't handle hugetlb properly. Actually in our testing, WARN_ON_ONCE(PageDirty(page)) at the end of this function fires for hugetlb, which makes no sense. So we should return immediately for hugetlb pages. Link: http://lkml.kernel.org/r/1496305019-5493-3-git-send-email-n-horiguchi@ah.jp.nec.com Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'for-linus-v4.13-2' of ↵Linus Torvalds2017-07-071-17/+109
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux Pull Writeback error handling updates from Jeff Layton: "This pile represents the bulk of the writeback error handling fixes that I have for this cycle. Some of the earlier patches in this pile may look trivial but they are prerequisites for later patches in the series. The aim of this set is to improve how we track and report writeback errors to userland. Most applications that care about data integrity will periodically call fsync/fdatasync/msync to ensure that their writes have made it to the backing store. For a very long time, we have tracked writeback errors using two flags in the address_space: AS_EIO and AS_ENOSPC. Those flags are set when a writeback error occurs (via mapping_set_error) and are cleared as a side-effect of filemap_check_errors (as you noted yesterday). This model really sucks for userland. Only the first task to call fsync (or msync or fdatasync) will see the error. Any subsequent task calling fsync on a file will get back 0 (unless another writeback error occurs in the interim). If I have several tasks writing to a file and calling fsync to ensure that their writes got stored, then I need to have them coordinate with one another. That's difficult enough, but in a world of containerized setups that coordination may even not be possible. But wait...it gets worse! The calls to filemap_check_errors can be buried pretty far down in the call stack, and there are internal callers of filemap_write_and_wait and the like that also end up clearing those errors. Many of those callers ignore the error return from that function or return it to userland at nonsensical times (e.g. truncate() or stat()). If I get back -EIO on a truncate, there is no reason to think that it was because some previous writeback failed, and a subsequent fsync() will (incorrectly) return 0. This pile aims to do three things: 1) ensure that when a writeback error occurs that that error will be reported to userland on a subsequent fsync/fdatasync/msync call, regardless of what internal callers are doing 2) report writeback errors on all file descriptions that were open at the time that the error occurred. This is a user-visible change, but I think most applications are written to assume this behavior anyway. Those that aren't are unlikely to be hurt by it. 3) document what filesystems should do when there is a writeback error. Today, there is very little consistency between them, and a lot of cargo-cult copying. We need to make it very clear what filesystems should do in this situation. To achieve this, the set adds a new data type (errseq_t) and then builds new writeback error tracking infrastructure around that. Once all of that is in place, we change the filesystems to use the new infrastructure for reporting wb errors to userland. Note that this is just the initial foray into cleaning up this mess. There is a lot of work remaining here: 1) convert the rest of the filesystems in a similar fashion. Once the initial set is in, then I think most other fs' will be fairly simple to convert. Hopefully most of those can in via individual filesystem trees. 2) convert internal waiters on writeback to use errseq_t for detecting errors instead of relying on the AS_* flags. I have some draft patches for this for ext4, but they are not quite ready for prime time yet. This was a discussion topic this year at LSF/MM too. If you're interested in the gory details, LWN has some good articles about this: https://lwn.net/Articles/718734/ https://lwn.net/Articles/724307/" * tag 'for-linus-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux: btrfs: minimal conversion to errseq_t writeback error reporting on fsync xfs: minimal conversion to errseq_t writeback error reporting ext4: use errseq_t based error handling for reporting data writeback errors fs: convert __generic_file_fsync to use errseq_t based reporting block: convert to errseq_t based writeback error tracking dax: set errors in mapping when writeback fails Documentation: flesh out the section in vfs.txt on storing and reporting writeback errors mm: set both AS_EIO/AS_ENOSPC and errseq_t in mapping_set_error fs: new infrastructure for writeback error handling and reporting lib: add errseq_t type and infrastructure for handling it mm: don't TestClearPageError in __filemap_fdatawait_range mm: clear AS_EIO/AS_ENOSPC when writeback initiation fails jbd2: don't clear and reset errors after waiting on writeback buffer: set errors in mapping at the time that the error occurs fs: check for writeback errors after syncing out buffers in generic_file_fsync buffer: use mapping_set_error instead of setting the flag mm: fix mapping_set_error call in me_pagecache_dirty
| * fs: new infrastructure for writeback error handling and reportingJeff Layton2017-07-061-0/+84
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most filesystems currently use mapping_set_error and filemap_check_errors for setting and reporting/clearing writeback errors at the mapping level. filemap_check_errors is indirectly called from most of the filemap_fdatawait_* functions and from filemap_write_and_wait*. These functions are called from all sorts of contexts to wait on writeback to finish -- e.g. mostly in fsync, but also in truncate calls, getattr, etc. The non-fsync callers are problematic. We should be reporting writeback errors during fsync, but many places spread over the tree clear out errors before they can be properly reported, or report errors at nonsensical times. If I get -EIO on a stat() call, there is no reason for me to assume that it is because some previous writeback failed. The fact that it also clears out the error such that a subsequent fsync returns 0 is a bug, and a nasty one since that's potentially silent data corruption. This patch adds a small bit of new infrastructure for setting and reporting errors during address_space writeback. While the above was my original impetus for adding this, I think it's also the case that current fsync semantics are just problematic for userland. Most applications that call fsync do so to ensure that the data they wrote has hit the backing store. In the case where there are multiple writers to the file at the same time, this is really hard to determine. The first one to call fsync will see any stored error, and the rest get back 0. The processes with open fds may not be associated with one another in any way. They could even be in different containers, so ensuring coordination between all fsync callers is not really an option. One way to remedy this would be to track what file descriptor was used to dirty the file, but that's rather cumbersome and would likely be slow. However, there is a simpler way to improve the semantics here without incurring too much overhead. This set adds an errseq_t to struct address_space, and a corresponding one is added to struct file. Writeback errors are recorded in the mapping's errseq_t, and the one in struct file is used as the "since" value. This changes the semantics of the Linux fsync implementation such that applications can now use it to determine whether there were any writeback errors since fsync(fd) was last called (or since the file was opened in the case of fsync having never been called). Note that those writeback errors may have occurred when writing data that was dirtied via an entirely different fd, but that's the case now with the current mapping_set_error/filemap_check_error infrastructure. This will at least prevent you from getting a false report of success. The new behavior is still consistent with the POSIX spec, and is more reliable for application developers. This patch just adds some basic infrastructure for doing this, and ensures that the f_wb_err "cursor" is properly set when a file is opened. Later patches will change the existing code to use this new infrastructure for reporting errors at fsync time. Signed-off-by: Jeff Layton <jlayton@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz>
| * mm: don't TestClearPageError in __filemap_fdatawait_rangeJeff Layton2017-07-061-15/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The -EIO returned here can end up overriding whatever error is marked in the address space, and be returned at fsync time, even when there is a more appropriate error stored in the mapping. Read errors are also sometimes tracked on a per-page level using PG_error. Suppose we have a read error on a page, and then that page is subsequently dirtied by overwriting the whole page. Writeback doesn't clear PG_error, so we can then end up successfully writing back that page and still return -EIO on fsync. Worse yet, PG_error is cleared during a sync() syscall, but the -EIO return from that is silently discarded. Any subsystem that is relying on PG_error to report errors during fsync can easily lose writeback errors due to this. All you need is a stray sync() call to wait for writeback to complete and you've lost the error. Since the handling of the PG_error flag is somewhat inconsistent across subsystems, let's just rely on marking the address space when there are writeback errors. Change the TestClearPageError call to ClearPageError, and make __filemap_fdatawait_range a void return function. Signed-off-by: Jeff Layton <jlayton@redhat.com>
| * mm: clear AS_EIO/AS_ENOSPC when writeback initiation failsJeff Layton2017-07-061-0/+6
| | | | | | | | | | | | | | | | | | | | filemap_write_and_wait{_range} will return an error if writeback initiation fails, but won't clear errors in the address_space. This is particularly problematic on DAX, as filemap_fdatawrite* is effectively synchronous there. Ensure that we clear the AS_EIO/AS_ENOSPC flags when filemap_fdatawrite* returns an error. Signed-off-by: Jeff Layton <jlayton@redhat.com>
| * jbd2: don't clear and reset errors after waiting on writebackJeff Layton2017-07-061-2/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | Resetting this flag is almost certainly racy, and will be problematic with some coming changes. Make filemap_fdatawait_keep_errors return int, but not clear the flag(s). Have jbd2 call it instead of filemap_fdatawait and don't attempt to re-set the error flag if it fails. Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Signed-off-by: Jeff Layton <jlayton@redhat.com>
* | mm: per-cgroup memory reclaim statsRoman Gushchin2017-07-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Track the following reclaim counters for every memory cgroup: PGREFILL, PGSCAN, PGSTEAL, PGACTIVATE, PGDEACTIVATE, PGLAZYFREE and PGLAZYFREED. These values are exposed using the memory.stats interface of cgroup v2. The meaning of each value is the same as for global counters, available using /proc/vmstat. Also, for consistency, rename mem_cgroup_count_vm_event() to count_memcg_event_mm(). Link: http://lkml.kernel.org/r/1494530183-30808-1-git-send-email-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2017-07-031-6/+6
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "The main changes in this cycle were: - Add the SYSTEM_SCHEDULING bootup state to move various scheduler debug checks earlier into the bootup. This turns silent and sporadically deadly bugs into nice, deterministic splats. Fix some of the splats that triggered. (Thomas Gleixner) - A round of restructuring and refactoring of the load-balancing and topology code (Peter Zijlstra) - Another round of consolidating ~20 of incremental scheduler code history: this time in terms of wait-queue nomenclature. (I didn't get much feedback on these renaming patches, and we can still easily change any names I might have misplaced, so if anyone hates a new name, please holler and I'll fix it.) (Ingo Molnar) - sched/numa improvements, fixes and updates (Rik van Riel) - Another round of x86/tsc scheduler clock code improvements, in hope of making it more robust (Peter Zijlstra) - Improve NOHZ behavior (Frederic Weisbecker) - Deadline scheduler improvements and fixes (Luca Abeni, Daniel Bristot de Oliveira) - Simplify and optimize the topology setup code (Lauro Ramos Venancio) - Debloat and decouple scheduler code some more (Nicolas Pitre) - Simplify code by making better use of llist primitives (Byungchul Park) - ... plus other fixes and improvements" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (103 commits) sched/cputime: Refactor the cputime_adjust() code sched/debug: Expose the number of RT/DL tasks that can migrate sched/numa: Hide numa_wake_affine() from UP build sched/fair: Remove effective_load() sched/numa: Implement NUMA node level wake_affine() sched/fair: Simplify wake_affine() for the single socket case sched/numa: Override part of migrate_degrades_locality() when idle balancing sched/rt: Move RT related code from sched/core.c to sched/rt.c sched/deadline: Move DL related code from sched/core.c to sched/deadline.c sched/cpuset: Only offer CONFIG_CPUSETS if SMP is enabled sched/fair: Spare idle load balancing on nohz_full CPUs nohz: Move idle balancer registration to the idle path sched/loadavg: Generalize "_idle" naming to "_nohz" sched/core: Drop the unused try_get_task_struct() helper function sched/fair: WARN() and refuse to set buddy when !se->on_rq sched/debug: Fix SCHED_WARN_ON() to return a value on !CONFIG_SCHED_DEBUG as well sched/wait: Disambiguate wq_entry->task_list and wq_head->task_list naming sched/wait: Move bit_wait_table[] and related functionality from sched/core.c to sched/wait_bit.c sched/wait: Split out the wait_bit*() APIs from <linux/wait.h> into <linux/wait_bit.h> sched/wait: Re-adjust macro line continuation backslashes in <linux/wait.h> ...
| * | sched/wait: Disambiguate wq_entry->task_list and wq_head->task_list namingIngo Molnar2017-06-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | So I've noticed a number of instances where it was not obvious from the code whether ->task_list was for a wait-queue head or a wait-queue entry. Furthermore, there's a number of wait-queue users where the lists are not for 'tasks' but other entities (poll tables, etc.), in which case the 'task_list' name is actively confusing. To clear this all up, name the wait-queue head and entry list structure fields unambiguously: struct wait_queue_head::task_list => ::head struct wait_queue_entry::task_list => ::entry For example, this code: rqw->wait.task_list.next != &wait->task_list ... is was pretty unclear (to me) what it's doing, while now it's written this way: rqw->wait.head.next != &wait->entry ... which makes it pretty clear that we are iterating a list until we see the head. Other examples are: list_for_each_entry_safe(pos, next, &x->task_list, task_list) { list_for_each_entry(wq, &fence->wait.task_list, task_list) { ... where it's unclear (to me) what we are iterating, and during review it's hard to tell whether it's trying to walk a wait-queue entry (which would be a bug), while now it's written as: list_for_each_entry_safe(pos, next, &x->head, entry) { list_for_each_entry(wq, &fence->wait.head, entry) { Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | sched/wait: Rename wait_queue_t => wait_queue_entry_tIngo Molnar2017-06-201-5/+5
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rename: wait_queue_t => wait_queue_entry_t 'wait_queue_t' was always a slight misnomer: its name implies that it's a "queue", but in reality it's a queue *entry*. The 'real' queue is the wait queue head, which had to carry the name. Start sorting this out by renaming it to 'wait_queue_entry_t'. This also allows the real structure name 'struct __wait_queue' to lose its double underscore and become 'struct wait_queue_entry', which is the more canonical nomenclature for such data types. Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | fs: return if direct I/O will trigger writebackGoldwyn Rodrigues2017-06-201-7/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Find out if the I/O will trigger a wait due to writeback. If yes, return -EAGAIN. Return -EINVAL for buffered AIO: there are multiple causes of delay such as page locks, dirty throttling logic, page loading from disk etc. which cannot be taken care of. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | fs: Introduce filemap_range_has_page()Goldwyn Rodrigues2017-06-201-0/+32
|/ | | | | | | | | | | | filemap_range_has_page() return true if the file's mapping has a page within the range mentioned. This function will be used to check if a write() call will cause a writeback of previous writes. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge branch 'work.iov_iter' of ↵Linus Torvalds2017-05-091-1/+1
|\ | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs fix from Al Viro: "Braino fix for iov_iter_revert() misuse" * 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fix braino in generic_file_read_iter()
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