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978 Commits
Author | SHA1 | Message | Date | |
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David Howells
|
74e797d79c |
mm: Provide a means of invalidation without using launder_folio
Implement a replacement for launder_folio. The key feature of invalidate_inode_pages2() is that it locks each folio individually, unmaps it to prevent mmap'd accesses interfering and calls the ->launder_folio() address_space op to flush it. This has problems: firstly, each folio is written individually as one or more small writes; secondly, adjacent folios cannot be added so easily into the laundry; thirdly, it's yet another op to implement. Instead, use the invalidate lock to cause anyone wanting to add a folio to the inode to wait, then unmap all the folios if we have mmaps, then, conditionally, use ->writepages() to flush any dirty data back and then discard all pages. The invalidate lock prevents ->read_iter(), ->write_iter() and faulting through mmap all from adding pages for the duration. This is then used from netfslib to handle the flusing in unbuffered and direct writes. Signed-off-by: David Howells <dhowells@redhat.com> cc: Matthew Wilcox <willy@infradead.org> cc: Miklos Szeredi <miklos@szeredi.hu> cc: Trond Myklebust <trond.myklebust@hammerspace.com> cc: Christoph Hellwig <hch@lst.de> cc: Andrew Morton <akpm@linux-foundation.org> cc: Alexander Viro <viro@zeniv.linux.org.uk> cc: Christian Brauner <brauner@kernel.org> cc: Jeff Layton <jlayton@kernel.org> cc: linux-mm@kvack.org cc: linux-fsdevel@vger.kernel.org cc: netfs@lists.linux.dev cc: v9fs@lists.linux.dev cc: linux-afs@lists.infradead.org cc: ceph-devel@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: linux-nfs@vger.kernel.org cc: devel@lists.orangefs.org |
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David Howells
|
2e9d7e4b98 |
mm: Remove the PG_fscache alias for PG_private_2
Remove the PG_fscache alias for PG_private_2 and use the latter directly. Use of this flag for marking pages undergoing writing to the cache should be considered deprecated and the folios should be marked dirty instead and the write done in ->writepages(). Note that PG_private_2 itself should be considered deprecated and up for future removal by the MM folks too. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: Matthew Wilcox (Oracle) <willy@infradead.org> cc: Ilya Dryomov <idryomov@gmail.com> cc: Xiubo Li <xiubli@redhat.com> cc: Steve French <sfrench@samba.org> cc: Paulo Alcantara <pc@manguebit.com> cc: Ronnie Sahlberg <ronniesahlberg@gmail.com> cc: Shyam Prasad N <sprasad@microsoft.com> cc: Tom Talpey <tom@talpey.com> cc: Bharath SM <bharathsm@microsoft.com> cc: Trond Myklebust <trond.myklebust@hammerspace.com> cc: Anna Schumaker <anna@kernel.org> cc: netfs@lists.linux.dev cc: ceph-devel@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: linux-nfs@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org |
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Johannes Weiner
|
d5d39c707a |
mm: cachestat: fix two shmem bugs
When cachestat on shmem races with swapping and invalidation, there
are two possible bugs:
1) A swapin error can have resulted in a poisoned swap entry in the
shmem inode's xarray. Calling get_shadow_from_swap_cache() on it
will result in an out-of-bounds access to swapper_spaces[].
Validate the entry with non_swap_entry() before going further.
2) When we find a valid swap entry in the shmem's inode, the shadow
entry in the swapcache might not exist yet: swap IO is still in
progress and we're before __remove_mapping; swapin, invalidation,
or swapoff have removed the shadow from swapcache after we saw the
shmem swap entry.
This will send a NULL to workingset_test_recent(). The latter
purely operates on pointer bits, so it won't crash - node 0, memcg
ID 0, eviction timestamp 0, etc. are all valid inputs - but it's a
bogus test. In theory that could result in a false "recently
evicted" count.
Such a false positive wouldn't be the end of the world. But for
code clarity and (future) robustness, be explicit about this case.
Bail on get_shadow_from_swap_cache() returning NULL.
Link: https://lkml.kernel.org/r/20240315095556.GC581298@cmpxchg.org
Fixes:
|
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Linus Torvalds
|
902861e34c |
- Sumanth Korikkar has taught s390 to allocate hotplug-time page frames
from hotplugged memory rather than only from main memory. Series "implement "memmap on memory" feature on s390". - More folio conversions from Matthew Wilcox in the series "Convert memcontrol charge moving to use folios" "mm: convert mm counter to take a folio" - Chengming Zhou has optimized zswap's rbtree locking, providing significant reductions in system time and modest but measurable reductions in overall runtimes. The series is "mm/zswap: optimize the scalability of zswap rb-tree". - Chengming Zhou has also provided the series "mm/zswap: optimize zswap lru list" which provides measurable runtime benefits in some swap-intensive situations. - And Chengming Zhou further optimizes zswap in the series "mm/zswap: optimize for dynamic zswap_pools". Measured improvements are modest. - zswap cleanups and simplifications from Yosry Ahmed in the series "mm: zswap: simplify zswap_swapoff()". - In the series "Add DAX ABI for memmap_on_memory", Vishal Verma has contributed several DAX cleanups as well as adding a sysfs tunable to control the memmap_on_memory setting when the dax device is hotplugged as system memory. - Johannes Weiner has added the large series "mm: zswap: cleanups", which does that. - More DAMON work from SeongJae Park in the series "mm/damon: make DAMON debugfs interface deprecation unignorable" "selftests/damon: add more tests for core functionalities and corner cases" "Docs/mm/damon: misc readability improvements" "mm/damon: let DAMOS feeds and tame/auto-tune itself" - In the series "mm/mempolicy: weighted interleave mempolicy and sysfs extension" Rakie Kim has developed a new mempolicy interleaving policy wherein we allocate memory across nodes in a weighted fashion rather than uniformly. This is beneficial in heterogeneous memory environments appearing with CXL. - Christophe Leroy has contributed some cleanup and consolidation work against the ARM pagetable dumping code in the series "mm: ptdump: Refactor CONFIG_DEBUG_WX and check_wx_pages debugfs attribute". - Luis Chamberlain has added some additional xarray selftesting in the series "test_xarray: advanced API multi-index tests". - Muhammad Usama Anjum has reworked the selftest code to make its human-readable output conform to the TAP ("Test Anything Protocol") format. Amongst other things, this opens up the use of third-party tools to parse and process out selftesting results. - Ryan Roberts has added fork()-time PTE batching of THP ptes in the series "mm/memory: optimize fork() with PTE-mapped THP". Mainly targeted at arm64, this significantly speeds up fork() when the process has a large number of pte-mapped folios. - David Hildenbrand also gets in on the THP pte batching game in his series "mm/memory: optimize unmap/zap with PTE-mapped THP". It implements batching during munmap() and other pte teardown situations. The microbenchmark improvements are nice. - And in the series "Transparent Contiguous PTEs for User Mappings" Ryan Roberts further utilizes arm's pte's contiguous bit ("contpte mappings"). Kernel build times on arm64 improved nicely. Ryan's series "Address some contpte nits" provides some followup work. - In the series "mm/hugetlb: Restore the reservation" Breno Leitao has fixed an obscure hugetlb race which was causing unnecessary page faults. He has also added a reproducer under the selftest code. - In the series "selftests/mm: Output cleanups for the compaction test", Mark Brown did what the title claims. - Kinsey Ho has added the series "mm/mglru: code cleanup and refactoring". - Even more zswap material from Nhat Pham. The series "fix and extend zswap kselftests" does as claimed. - In the series "Introduce cpu_dcache_is_aliasing() to fix DAX regression" Mathieu Desnoyers has cleaned up and fixed rather a mess in our handling of DAX on archiecctures which have virtually aliasing data caches. The arm architecture is the main beneficiary. - Lokesh Gidra's series "per-vma locks in userfaultfd" provides dramatic improvements in worst-case mmap_lock hold times during certain userfaultfd operations. - Some page_owner enhancements and maintenance work from Oscar Salvador in his series "page_owner: print stacks and their outstanding allocations" "page_owner: Fixup and cleanup" - Uladzislau Rezki has contributed some vmalloc scalability improvements in his series "Mitigate a vmap lock contention". It realizes a 12x improvement for a certain microbenchmark. - Some kexec/crash cleanup work from Baoquan He in the series "Split crash out from kexec and clean up related config items". - Some zsmalloc maintenance work from Chengming Zhou in the series "mm/zsmalloc: fix and optimize objects/page migration" "mm/zsmalloc: some cleanup for get/set_zspage_mapping()" - Zi Yan has taught the MM to perform compaction on folios larger than order=0. This a step along the path to implementaton of the merging of large anonymous folios. The series is named "Enable >0 order folio memory compaction". - Christoph Hellwig has done quite a lot of cleanup work in the pagecache writeback code in his series "convert write_cache_pages() to an iterator". - Some modest hugetlb cleanups and speedups in Vishal Moola's series "Handle hugetlb faults under the VMA lock". - Zi Yan has changed the page splitting code so we can split huge pages into sizes other than order-0 to better utilize large folios. The series is named "Split a folio to any lower order folios". - David Hildenbrand has contributed the series "mm: remove total_mapcount()", a cleanup. - Matthew Wilcox has sought to improve the performance of bulk memory freeing in his series "Rearrange batched folio freeing". - Gang Li's series "hugetlb: parallelize hugetlb page init on boot" provides large improvements in bootup times on large machines which are configured to use large numbers of hugetlb pages. - Matthew Wilcox's series "PageFlags cleanups" does that. - Qi Zheng's series "minor fixes and supplement for ptdesc" does that also. S390 is affected. - Cleanups to our pagemap utility functions from Peter Xu in his series "mm/treewide: Replace pXd_large() with pXd_leaf()". - Nico Pache has fixed a few things with our hugepage selftests in his series "selftests/mm: Improve Hugepage Test Handling in MM Selftests". - Also, of course, many singleton patches to many things. Please see the individual changelogs for details. -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZfJpPQAKCRDdBJ7gKXxA joxeAP9TrcMEuHnLmBlhIXkWbIR4+ki+pA3v+gNTlJiBhnfVSgD9G55t1aBaRplx TMNhHfyiHYDTx/GAV9NXW84tasJSDgA= =TG55 -----END PGP SIGNATURE----- Merge tag 'mm-stable-2024-03-13-20-04' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Sumanth Korikkar has taught s390 to allocate hotplug-time page frames from hotplugged memory rather than only from main memory. Series "implement "memmap on memory" feature on s390". - More folio conversions from Matthew Wilcox in the series "Convert memcontrol charge moving to use folios" "mm: convert mm counter to take a folio" - Chengming Zhou has optimized zswap's rbtree locking, providing significant reductions in system time and modest but measurable reductions in overall runtimes. The series is "mm/zswap: optimize the scalability of zswap rb-tree". - Chengming Zhou has also provided the series "mm/zswap: optimize zswap lru list" which provides measurable runtime benefits in some swap-intensive situations. - And Chengming Zhou further optimizes zswap in the series "mm/zswap: optimize for dynamic zswap_pools". Measured improvements are modest. - zswap cleanups and simplifications from Yosry Ahmed in the series "mm: zswap: simplify zswap_swapoff()". - In the series "Add DAX ABI for memmap_on_memory", Vishal Verma has contributed several DAX cleanups as well as adding a sysfs tunable to control the memmap_on_memory setting when the dax device is hotplugged as system memory. - Johannes Weiner has added the large series "mm: zswap: cleanups", which does that. - More DAMON work from SeongJae Park in the series "mm/damon: make DAMON debugfs interface deprecation unignorable" "selftests/damon: add more tests for core functionalities and corner cases" "Docs/mm/damon: misc readability improvements" "mm/damon: let DAMOS feeds and tame/auto-tune itself" - In the series "mm/mempolicy: weighted interleave mempolicy and sysfs extension" Rakie Kim has developed a new mempolicy interleaving policy wherein we allocate memory across nodes in a weighted fashion rather than uniformly. This is beneficial in heterogeneous memory environments appearing with CXL. - Christophe Leroy has contributed some cleanup and consolidation work against the ARM pagetable dumping code in the series "mm: ptdump: Refactor CONFIG_DEBUG_WX and check_wx_pages debugfs attribute". - Luis Chamberlain has added some additional xarray selftesting in the series "test_xarray: advanced API multi-index tests". - Muhammad Usama Anjum has reworked the selftest code to make its human-readable output conform to the TAP ("Test Anything Protocol") format. Amongst other things, this opens up the use of third-party tools to parse and process out selftesting results. - Ryan Roberts has added fork()-time PTE batching of THP ptes in the series "mm/memory: optimize fork() with PTE-mapped THP". Mainly targeted at arm64, this significantly speeds up fork() when the process has a large number of pte-mapped folios. - David Hildenbrand also gets in on the THP pte batching game in his series "mm/memory: optimize unmap/zap with PTE-mapped THP". It implements batching during munmap() and other pte teardown situations. The microbenchmark improvements are nice. - And in the series "Transparent Contiguous PTEs for User Mappings" Ryan Roberts further utilizes arm's pte's contiguous bit ("contpte mappings"). Kernel build times on arm64 improved nicely. Ryan's series "Address some contpte nits" provides some followup work. - In the series "mm/hugetlb: Restore the reservation" Breno Leitao has fixed an obscure hugetlb race which was causing unnecessary page faults. He has also added a reproducer under the selftest code. - In the series "selftests/mm: Output cleanups for the compaction test", Mark Brown did what the title claims. - Kinsey Ho has added the series "mm/mglru: code cleanup and refactoring". - Even more zswap material from Nhat Pham. The series "fix and extend zswap kselftests" does as claimed. - In the series "Introduce cpu_dcache_is_aliasing() to fix DAX regression" Mathieu Desnoyers has cleaned up and fixed rather a mess in our handling of DAX on archiecctures which have virtually aliasing data caches. The arm architecture is the main beneficiary. - Lokesh Gidra's series "per-vma locks in userfaultfd" provides dramatic improvements in worst-case mmap_lock hold times during certain userfaultfd operations. - Some page_owner enhancements and maintenance work from Oscar Salvador in his series "page_owner: print stacks and their outstanding allocations" "page_owner: Fixup and cleanup" - Uladzislau Rezki has contributed some vmalloc scalability improvements in his series "Mitigate a vmap lock contention". It realizes a 12x improvement for a certain microbenchmark. - Some kexec/crash cleanup work from Baoquan He in the series "Split crash out from kexec and clean up related config items". - Some zsmalloc maintenance work from Chengming Zhou in the series "mm/zsmalloc: fix and optimize objects/page migration" "mm/zsmalloc: some cleanup for get/set_zspage_mapping()" - Zi Yan has taught the MM to perform compaction on folios larger than order=0. This a step along the path to implementaton of the merging of large anonymous folios. The series is named "Enable >0 order folio memory compaction". - Christoph Hellwig has done quite a lot of cleanup work in the pagecache writeback code in his series "convert write_cache_pages() to an iterator". - Some modest hugetlb cleanups and speedups in Vishal Moola's series "Handle hugetlb faults under the VMA lock". - Zi Yan has changed the page splitting code so we can split huge pages into sizes other than order-0 to better utilize large folios. The series is named "Split a folio to any lower order folios". - David Hildenbrand has contributed the series "mm: remove total_mapcount()", a cleanup. - Matthew Wilcox has sought to improve the performance of bulk memory freeing in his series "Rearrange batched folio freeing". - Gang Li's series "hugetlb: parallelize hugetlb page init on boot" provides large improvements in bootup times on large machines which are configured to use large numbers of hugetlb pages. - Matthew Wilcox's series "PageFlags cleanups" does that. - Qi Zheng's series "minor fixes and supplement for ptdesc" does that also. S390 is affected. - Cleanups to our pagemap utility functions from Peter Xu in his series "mm/treewide: Replace pXd_large() with pXd_leaf()". - Nico Pache has fixed a few things with our hugepage selftests in his series "selftests/mm: Improve Hugepage Test Handling in MM Selftests". - Also, of course, many singleton patches to many things. Please see the individual changelogs for details. * tag 'mm-stable-2024-03-13-20-04' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (435 commits) mm/zswap: remove the memcpy if acomp is not sleepable crypto: introduce: acomp_is_async to expose if comp drivers might sleep memtest: use {READ,WRITE}_ONCE in memory scanning mm: prohibit the last subpage from reusing the entire large folio mm: recover pud_leaf() definitions in nopmd case selftests/mm: skip the hugetlb-madvise tests on unmet hugepage requirements selftests/mm: skip uffd hugetlb tests with insufficient hugepages selftests/mm: dont fail testsuite due to a lack of hugepages mm/huge_memory: skip invalid debugfs new_order input for folio split mm/huge_memory: check new folio order when split a folio mm, vmscan: retry kswapd's priority loop with cache_trim_mode off on failure mm: add an explicit smp_wmb() to UFFDIO_CONTINUE mm: fix list corruption in put_pages_list mm: remove folio from deferred split list before uncharging it filemap: avoid unnecessary major faults in filemap_fault() mm,page_owner: drop unnecessary check mm,page_owner: check for null stack_record before bumping its refcount mm: swap: fix race between free_swap_and_cache() and swapoff() mm/treewide: align up pXd_leaf() retval across archs mm/treewide: drop pXd_large() ... |
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Linus Torvalds
|
babbcc0232 |
New code for 6.9:
* Online Repair; ** New ondisk structures being repaired. - Inode's mode field by trying to obtain file type value from the a directory entry. - Quota counters. - Link counts of inodes. - FS summary counters. - rmap btrees. Support for in-memory btrees has been added to support repair of rmap btrees. ** Misc changes - Report corruption of metadata to the health tracking subsystem. - Enable indirect health reporting when resources are scarce. - Reduce memory usage while reparing refcount btree. - Extend "Bmap update" intent item to support atomic extent swapping on the realtime device. - Extend "Bmap update" intent item to support extended attribute fork and unwritten extents. ** Code cleanups - Bmap log intent. - Btree block pointer checking. - Btree readahead. - Buffer target. - Symbolic link code. * Remove mrlock wrapper around the rwsem. * Convert all the GFP_NOFS flag usages to use the scoped memalloc_nofs_save() API instead of direct calls with the GFP_NOFS. * Refactor and simplify xfile abstraction. Lower level APIs in shmem.c are required to be exported in order to achieve this. * Skip checking alignment constraints for inode chunk allocations when block size is larger than inode chunk size. * Do not submit delwri buffers collected during log recovery when an error has been encountered. * Fix SEEK_HOLE/DATA for file regions which have active COW extents. * Fix lock order inversion when executing error handling path during shrinking a filesystem. * Remove duplicate ifdefs. Signed-off-by: Chandan Babu R <chandanbabu@kernel.org> -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQQjMC4mbgVeU7MxEIYH7y4RirJu9AUCZemMkgAKCRAH7y4RirJu 9ON5AP0Vda6sMn/ZUYoLo9ZUrUvlUb8L0dhEN5JL0XfyWW5ogAD/bH4G6pKSNyTw cSEjryuDakirdHLt5g0c+QHd2a/fzw0= =ymKk -----END PGP SIGNATURE----- Merge tag 'xfs-6.9-merge-8' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux Pull xfs updates from Chandan Babu: - Online repair updates: - More ondisk structures being repaired: - Inode's mode field by trying to obtain file type value from the a directory entry - Quota counters - Link counts of inodes - FS summary counters - Support for in-memory btrees has been added to support repair of rmap btrees - Misc changes: - Report corruption of metadata to the health tracking subsystem - Enable indirect health reporting when resources are scarce - Reduce memory usage while repairing refcount btree - Extend "Bmap update" intent item to support atomic extent swapping on the realtime device - Extend "Bmap update" intent item to support extended attribute fork and unwritten extents - Code cleanups: - Bmap log intent - Btree block pointer checking - Btree readahead - Buffer target - Symbolic link code - Remove mrlock wrapper around the rwsem - Convert all the GFP_NOFS flag usages to use the scoped memalloc_nofs_save() API instead of direct calls with the GFP_NOFS - Refactor and simplify xfile abstraction. Lower level APIs in shmem.c are required to be exported in order to achieve this - Skip checking alignment constraints for inode chunk allocations when block size is larger than inode chunk size - Do not submit delwri buffers collected during log recovery when an error has been encountered - Fix SEEK_HOLE/DATA for file regions which have active COW extents - Fix lock order inversion when executing error handling path during shrinking a filesystem - Remove duplicate ifdefs * tag 'xfs-6.9-merge-8' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (183 commits) xfs: shrink failure needs to hold AGI buffer mm/shmem.c: Use new form of *@param in kernel-doc kernel-doc: Add unary operator * to $type_param_ref xfs: use kvfree() in xlog_cil_free_logvec() xfs: xfs_btree_bload_prep_block() should use __GFP_NOFAIL xfs: fix scrub stats file permissions xfs: fix log recovery erroring out on refcount recovery failure xfs: move symlink target write function to libxfs xfs: move remote symlink target read function to libxfs xfs: move xfs_symlink_remote.c declarations to xfs_symlink_remote.h xfs: xfs_bmap_finish_one should map unwritten extents properly xfs: support deferred bmap updates on the attr fork xfs: support recovering bmap intent items targetting realtime extents xfs: add a realtime flag to the bmap update log redo items xfs: add a xattr_entry helper xfs: fix xfs_bunmapi to allow unmapping of partial rt extents xfs: move xfs_bmap_defer_add to xfs_bmap_item.c xfs: reuse xfs_bmap_update_cancel_item xfs: add a bi_entry helper xfs: remove xfs_trans_set_bmap_flags ... |
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Linus Torvalds
|
7ea65c89d8 |
vfs-6.9.misc
-----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCZem3wQAKCRCRxhvAZXjc otRMAQDeo8qsuuIAcS2KUicKqZR5yMVvrY9r4sQzf7YRcJo5HQD+NQXkKwQuv1VO OUeScsic/+I+136AgdjWnlEYO5dp0go= =4WKU -----END PGP SIGNATURE----- Merge tag 'vfs-6.9.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull misc vfs updates from Christian Brauner: "Misc features, cleanups, and fixes for vfs and individual filesystems. Features: - Support idmapped mounts for hugetlbfs. - Add RWF_NOAPPEND flag for pwritev2(). This allows us to fix a bug where the passed offset is ignored if the file is O_APPEND. The new flag allows a caller to enforce that the offset is honored to conform to posix even if the file was opened in append mode. - Move i_mmap_rwsem in struct address_space to avoid false sharing between i_mmap and i_mmap_rwsem. - Convert efs, qnx4, and coda to use the new mount api. - Add a generic is_dot_dotdot() helper that's used by various filesystems and the VFS code instead of open-coding it multiple times. - Recently we've added stable offsets which allows stable ordering when iterating directories exported through NFS on e.g., tmpfs filesystems. Originally an xarray was used for the offset map but that caused slab fragmentation issues over time. This switches the offset map to the maple tree which has a dense mode that handles this scenario a lot better. Includes tests. - Finally merge the case-insensitive improvement series Gabriel has been working on for a long time. This cleanly propagates case insensitive operations through ->s_d_op which in turn allows us to remove the quite ugly generic_set_encrypted_ci_d_ops() operations. It also improves performance by trying a case-sensitive comparison first and then fallback to case-insensitive lookup if that fails. This also fixes a bug where overlayfs would be able to be mounted over a case insensitive directory which would lead to all sort of odd behaviors. Cleanups: - Make file_dentry() a simple accessor now that ->d_real() is simplified because of the backing file work we did the last two cycles. - Use the dedicated file_mnt_idmap helper in ntfs3. - Use smp_load_acquire/store_release() in the i_size_read/write helpers and thus remove the hack to handle i_size reads in the filemap code. - The SLAB_MEM_SPREAD is a nop now. Remove it from various places in fs/ - It's no longer necessary to perform a second built-in initramfs unpack call because we retain the contents of the previous extraction. Remove it. - Now that we have removed various allocators kfree_rcu() always works with kmem caches and kmalloc(). So simplify various places that only use an rcu callback in order to handle the kmem cache case. - Convert the pipe code to use a lockdep comparison function instead of open-coding the nesting making lockdep validation easier. - Move code into fs-writeback.c that was located in a header but can be made static as it's only used in that one file. - Rewrite the alignment checking iterators for iovec and bvec to be easier to read, and also significantly more compact in terms of generated code. This saves 270 bytes of text on x86-64 (with clang-18) and 224 bytes on arm64 (with gcc-13). In profiles it also saves a bit of time for the same workload. - Switch various places to use KMEM_CACHE instead of kmem_cache_create(). - Use inode_set_ctime_to_ts() in inode_set_ctime_current() - Use kzalloc() in name_to_handle_at() to avoid kernel infoleak. - Various smaller cleanups for eventfds. Fixes: - Fix various comments and typos, and unneeded initializations. - Fix stack allocation hack for clang in the select code. - Improve dump_mapping() debug code on a best-effort basis. - Fix build errors in various selftests. - Avoid wrap-around instrumentation in various places. - Don't allow user namespaces without an idmapping to be used for idmapped mounts. - Fix sysv sb_read() call. - Fix fallback implementation of the get_name() export operation" * tag 'vfs-6.9.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (70 commits) hugetlbfs: support idmapped mounts qnx4: convert qnx4 to use the new mount api fs: use inode_set_ctime_to_ts to set inode ctime to current time libfs: Drop generic_set_encrypted_ci_d_ops ubifs: Configure dentry operations at dentry-creation time f2fs: Configure dentry operations at dentry-creation time ext4: Configure dentry operations at dentry-creation time libfs: Add helper to choose dentry operations at mount-time libfs: Merge encrypted_ci_dentry_ops and ci_dentry_ops fscrypt: Drop d_revalidate once the key is added fscrypt: Drop d_revalidate for valid dentries during lookup fscrypt: Factor out a helper to configure the lookup dentry ovl: Always reject mounting over case-insensitive directories libfs: Attempt exact-match comparison first during casefolded lookup efs: remove SLAB_MEM_SPREAD flag usage jfs: remove SLAB_MEM_SPREAD flag usage minix: remove SLAB_MEM_SPREAD flag usage openpromfs: remove SLAB_MEM_SPREAD flag usage proc: remove SLAB_MEM_SPREAD flag usage qnx6: remove SLAB_MEM_SPREAD flag usage ... |
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ZhangPeng
|
58f327f2ce |
filemap: avoid unnecessary major faults in filemap_fault()
A major fault occurred when using mlockall(MCL_CURRENT | MCL_FUTURE) in application, which leading to an unexpected issue[1]. This is caused by temporarily cleared PTE during a read+clear/modify/write update of the PTE, eg, do_numa_page()/change_pte_range(). For the data segment of the user-mode program, the global variable area is a private mapping. After the pagecache is loaded, the private anonymous page is generated after the COW is triggered. Mlockall can lock COW pages (anonymous pages), but the original file pages cannot be locked and may be reclaimed. If the global variable (private anon page) is accessed when vmf->pte is zeroed in numa fault, a file page fault will be triggered. At this time, the original private file page may have been reclaimed. If the page cache is not available at this time, a major fault will be triggered and the file will be read, causing additional overhead. This issue affects our traffic analysis service. The inbound traffic is heavy. If a major fault occurs, the I/O schedule is triggered and the original I/O is suspended. Generally, the I/O schedule is 0.7 ms. If other applications are operating disks, the system needs to wait for more than 10 ms. However, the inbound traffic is heavy and the NIC buffer is small. As a result, packet loss occurs. But the traffic analysis service can't tolerate packet loss. Fix this by holding PTL and rechecking the PTE in filemap_fault() before triggering a major fault. We do this check only if vma is VM_LOCKED to reduce the performance impact in common scenarios. In our product environment, there were 7 major faults every 12 hours. After the patch is applied, no major fault have been triggered. Testing file page read and write page fault performance in ext4 and ramdisk using will-it-scale[2] on a x86 physical machine. The data is the average change compared with the mainline after the patch is applied. The test results are within the range of fluctuation. We do this check only if vma is VM_LOCKED, therefore, no performance regressions is caused for most common cases. The test results are as follows: processes processes_idle threads threads_idle ext4 private file write: 0.22% 0.26% 1.21% -0.15% ext4 private file read: 0.03% 1.00% 1.39% 0.34% ext4 shared file write: -0.50% -0.02% -0.14% -0.02% ramdisk private file write: 0.07% 0.02% 0.53% 0.04% ramdisk private file read: 0.01% 1.60% -0.32% -0.02% [1] https://lore.kernel.org/linux-mm/9e62fd9a-bee0-52bf-50a7-498fa17434ee@huawei.com/ [2] https://github.com/antonblanchard/will-it-scale/ Link: https://lkml.kernel.org/r/20240306083809.1236634-1-zhangpeng362@huawei.com Signed-off-by: ZhangPeng <zhangpeng362@huawei.com> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Suggested-by: "Huang, Ying" <ying.huang@intel.com> Suggested-by: David Hildenbrand <david@redhat.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
8897277acf |
mm: support order-1 folios in the page cache
Folios of order 1 have no space to store the deferred list. This is not a problem for the page cache as file-backed folios are never placed on the deferred list. All we need to do is prevent the core MM from touching the deferred list for order 1 folios and remove the code which prevented us from allocating order 1 folios. Link: https://lore.kernel.org/linux-mm/90344ea7-4eec-47ee-5996-0c22f42d6a6a@google.com/ Link: https://lkml.kernel.org/r/20240226205534.1603748-3-zi.yan@sent.com Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Zi Yan <ziy@nvidia.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Michal Koutny <mkoutny@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Andrew Morton
|
1f1183c4c0 | merge mm-hotfixes-stable into mm-nonmm-stable to pick up stackdepot changes | ||
Nhat Pham
|
3a75cb05d5 |
mm: cachestat: fix folio read-after-free in cache walk
In cachestat, we access the folio from the page cache's xarray to compute
its page offset, and check for its dirty and writeback flags. However, we
do not hold a reference to the folio before performing these actions,
which means the folio can concurrently be released and reused as another
folio/page/slab.
Get around this altogether by just using xarray's existing machinery for
the folio page offsets and dirty/writeback states.
This changes behavior for tmpfs files to now always report zeroes in their
dirty and writeback counters. This is okay as tmpfs doesn't follow
conventional writeback cache behavior: its pages get "cleaned" during
swapout, after which they're no longer resident etc.
Link: https://lkml.kernel.org/r/20240220153409.GA216065@cmpxchg.org
Fixes:
|
||
Matthew Wilcox (Oracle)
|
5662400a9a |
mm: add pfn_swap_entry_folio()
Patch series "mm: convert mm counter to take a folio", v3. Make sure all mm_counter() and mm_counter_file() callers have a folio, then convert mm counter functions to take a folio, which saves some compound_head() calls. This patch (of 10): Thanks to the compound_head() hidden inside PageLocked(), this saves a call to compound_head() over calling page_folio(pfn_swap_entry_to_page()) Link: https://lkml.kernel.org/r/20240111152429.3374566-1-willy@infradead.org Link: https://lkml.kernel.org/r/20240111152429.3374566-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Hongbo Li
|
6212eb4d7a |
mm/filemap: avoid type conversion
The return type of function folio_test_hugetlb is bool type, there is no need to assign it to an integer type. Link: https://lkml.kernel.org/r/20240108044815.3291487-1-lihongbo22@huawei.com Signed-off-by: Hongbo Li <lihongbo22@huawei.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Christoph Hellwig
|
b64e74e95a |
mm: move mapping_set_update out of <linux/swap.h>
mapping_set_update is only used inside mm/. Move mapping_set_update to mm/internal.h and turn it into an inline function instead of a macro. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Matthew Wilcox (Oracle)" <willy@infradead.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org> |
||
Baokun Li
|
4b944f8ef9 |
Revert "mm/filemap: avoid buffered read/write race to read inconsistent data"
This reverts commit
|
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Linus Torvalds
|
16df6e07d6 |
vfs-6.8.netfs
-----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCZabMrQAKCRCRxhvAZXjc ovnUAQDgCOonb1tjtTvC8s8IMDUEoaVYZI91KVfsZQSJYN1sdQD+KfJmX1BhJnWG l0cEffGfnWGXMZkZqDgLPHUIPzFrmws= =1b3j -----END PGP SIGNATURE----- Merge tag 'vfs-6.8.netfs' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs Pull netfs updates from Christian Brauner: "This extends the netfs helper library that network filesystems can use to replace their own implementations. Both afs and 9p are ported. cifs is ready as well but the patches are way bigger and will be routed separately once this is merged. That will remove lots of code as well. The overal goal is to get high-level I/O and knowledge of the page cache and ouf of the filesystem drivers. This includes knowledge about the existence of pages and folios The pull request converts afs and 9p. This removes about 800 lines of code from afs and 300 from 9p. For 9p it is now possible to do writes in larger than a page chunks. Additionally, multipage folio support can be turned on for 9p. Separate patches exist for cifs removing another 2000+ lines. I've included detailed information in the individual pulls I took. Summary: - Add NFS-style (and Ceph-style) locking around DIO vs buffered I/O calls to prevent these from happening at the same time. - Support for direct and unbuffered I/O. - Support for write-through caching in the page cache. - O_*SYNC and RWF_*SYNC writes use write-through rather than writing to the page cache and then flushing afterwards. - Support for write-streaming. - Support for write grouping. - Skip reads for which the server could only return zeros or EOF. - The fscache module is now part of the netfs library and the corresponding maintainer entry is updated. - Some helpers from the fscache subsystem are renamed to mark them as belonging to the netfs library. - Follow-up fixes for the netfs library. - Follow-up fixes for the 9p conversion" * tag 'vfs-6.8.netfs' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (50 commits) netfs: Fix wrong #ifdef hiding wait cachefiles: Fix signed/unsigned mixup netfs: Fix the loop that unmarks folios after writing to the cache netfs: Fix interaction between write-streaming and cachefiles culling netfs: Count DIO writes netfs: Mark netfs_unbuffered_write_iter_locked() static netfs: Fix proc/fs/fscache symlink to point to "netfs" not "../netfs" netfs: Rearrange netfs_io_subrequest to put request pointer first 9p: Use length of data written to the server in preference to error 9p: Do a couple of cleanups 9p: Fix initialisation of netfs_inode for 9p cachefiles: Fix __cachefiles_prepare_write() 9p: Use netfslib read/write_iter afs: Use the netfs write helpers netfs: Export the netfs_sreq tracepoint netfs: Optimise away reads above the point at which there can be no data netfs: Implement a write-through caching option netfs: Provide a launder_folio implementation netfs: Provide a writepages implementation netfs, cachefiles: Pass upper bound length to allow expansion ... |
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Linus Torvalds
|
78273df7f6 |
header cleanups for 6.8
The goal is to get sched.h down to a type only header, so the main thing happening in this patchset is splitting out various _types.h headers and dependency fixups, as well as moving some things out of sched.h to better locations. This is prep work for the memory allocation profiling patchset which adds new sched.h interdepencencies. Testing - it's been in -next, and fixes from pretty much all architectures have percolated in - nothing major. -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEKnAFLkS8Qha+jvQrE6szbY3KbnYFAmWfBwwACgkQE6szbY3K bnZPwBAAmuRojXaeWxi01IPIOehSGDe68vw44PR9glEMZvxdnZuPOdvE4/+245/L bRKU2WBCjBUokUbV9msIShwRkFTZAmEMPNfPAAsFMA+VXeDYHKB+ZRdwTggNAQ+I SG6fZgh5m0HsewCDxU8oqVHkjVq4fXn0cy+aL6xLEd9gu67GoBzX2pDieS2Kvy6j jnyoKTxFwb+LTQgph0P4EIpq5I2umAsdLwdSR8EJ+8e9NiNvMo1pI00Lx/ntAnFZ JftWUJcMy3TQ5u1GkyfQN9y/yThX1bZK5GvmHS9SJ2Dkacaus5d+xaKCHtRuFS1I 7C6b8PsNgRczUMumBXus44HdlNfNs1yU3lvVxFvBIPE1qC9pYRHrkWIXXIocXLLC oxTEJ6B2G3BQZVQgLIA4fOaxMVhmvKffi/aEZLi9vN9VVosd1a6XNKI6KbyRnXFp GSs9qDqszhn5I3GYNlDNQTc/8UsRlhPFgS6nS0By6QnvxtGi9QkU2tBRBsXvqwCy cLoCYIhc2tvugHvld70dz26umiJ4rnmxGlobStNoigDvIKAIUt1UmIdr1so8P8eH xehnL9ZcOX6xnANDL0AqMFFHV6I58CJynhFdUoXfVQf/DWLGX48mpi9LVNsYBzsI CAwVOAQ0UjGrpdWmJ9ueY/ABYqg9vRjzaDEXQ+MhAYO55CLaVsg= =3tyT -----END PGP SIGNATURE----- Merge tag 'header_cleanup-2024-01-10' of https://evilpiepirate.org/git/bcachefs Pull header cleanups from Kent Overstreet: "The goal is to get sched.h down to a type only header, so the main thing happening in this patchset is splitting out various _types.h headers and dependency fixups, as well as moving some things out of sched.h to better locations. This is prep work for the memory allocation profiling patchset which adds new sched.h interdepencencies" * tag 'header_cleanup-2024-01-10' of https://evilpiepirate.org/git/bcachefs: (51 commits) Kill sched.h dependency on rcupdate.h kill unnecessary thread_info.h include Kill unnecessary kernel.h include preempt.h: Kill dependency on list.h rseq: Split out rseq.h from sched.h LoongArch: signal.c: add header file to fix build error restart_block: Trim includes lockdep: move held_lock to lockdep_types.h sem: Split out sem_types.h uidgid: Split out uidgid_types.h seccomp: Split out seccomp_types.h refcount: Split out refcount_types.h uapi/linux/resource.h: fix include x86/signal: kill dependency on time.h syscall_user_dispatch.h: split out *_types.h mm_types_task.h: Trim dependencies Split out irqflags_types.h ipc: Kill bogus dependency on spinlock.h shm: Slim down dependencies workqueue: Split out workqueue_types.h ... |
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David Hildenbrand
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4d8f7418e8 |
mm/rmap: remove page_remove_rmap()
All callers are gone, let's remove it and some leftover traces. Link: https://lkml.kernel.org/r/20231220224504.646757-33-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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David Howells
|
153a9961b5 |
netfs: Implement unbuffered/DIO write support
Implement support for unbuffered writes and direct I/O writes. If the write is misaligned with respect to the fscrypt block size, then RMW cycles are performed if necessary. DIO writes are a special case of unbuffered writes with extra restriction imposed, such as block size alignment requirements. Also provide a field that can tell the code to add some extra space onto the bounce buffer for use by the filesystem in the case of a content-encrypted file. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org |
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David Howells
|
016dc8516a |
netfs: Implement unbuffered/DIO read support
Implement support for unbuffered and DIO reads in the netfs library, utilising the existing read helper code to do block splitting and individual queuing. The code also handles extraction of the destination buffer from the supplied iterator, allowing async unbuffered reads to take place. The read will be split up according to the rsize setting and, if supplied, the ->clamp_length() method. Note that the next subrequest will be issued as soon as issue_op returns, without waiting for previous ones to finish. The network filesystem needs to pause or handle queuing them if it doesn't want to fire them all at the server simultaneously. Once all the subrequests have finished, the state will be assessed and the amount of data to be indicated as having being obtained will be determined. As the subrequests may finish in any order, if an intermediate subrequest is short, any further subrequests may be copied into the buffer and then abandoned. In the future, this will also take care of doing an unbuffered read from encrypted content, with the decryption being done by the library. Signed-off-by: David Howells <dhowells@redhat.com> cc: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org |
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Kent Overstreet
|
1e2f2d3199 |
Kill sched.h dependency on rcupdate.h
by moving cond_resched_rcu() to rcupdate_wait.h, we can kill another big sched.h dependency. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev> |
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Andrew Morton
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a721aeac8b | sync mm-stable with mm-hotfixes-stable to pick up depended-upon changes | ||
Baokun Li
|
e2c27b803b |
mm/filemap: avoid buffered read/write race to read inconsistent data
The following concurrency may cause the data read to be inconsistent with the data on disk: cpu1 cpu2 ------------------------------|------------------------------ // Buffered write 2048 from 0 ext4_buffered_write_iter generic_perform_write copy_page_from_iter_atomic ext4_da_write_end ext4_da_do_write_end block_write_end __block_commit_write folio_mark_uptodate // Buffered read 4096 from 0 smp_wmb() ext4_file_read_iter set_bit(PG_uptodate, folio_flags) generic_file_read_iter i_size_write // 2048 filemap_read unlock_page(page) filemap_get_pages filemap_get_read_batch folio_test_uptodate(folio) ret = test_bit(PG_uptodate, folio_flags) if (ret) smp_rmb(); // Ensure that the data in page 0-2048 is up-to-date. // New buffered write 2048 from 2048 ext4_buffered_write_iter generic_perform_write copy_page_from_iter_atomic ext4_da_write_end ext4_da_do_write_end block_write_end __block_commit_write folio_mark_uptodate smp_wmb() set_bit(PG_uptodate, folio_flags) i_size_write // 4096 unlock_page(page) isize = i_size_read(inode) // 4096 // Read the latest isize 4096, but without smp_rmb(), there may be // Load-Load disorder resulting in the data in the 2048-4096 range // in the page is not up-to-date. copy_page_to_iter // copyout 4096 In the concurrency above, we read the updated i_size, but there is no read barrier to ensure that the data in the page is the same as the i_size at this point, so we may copy the unsynchronized page out. Hence adding the missing read memory barrier to fix this. This is a Load-Load reordering issue, which only occurs on some weak mem-ordering architectures (e.g. ARM64, ALPHA), but not on strong mem-ordering architectures (e.g. X86). And theoretically the problem doesn't only happen on ext4, filesystems that call filemap_read() but don't hold inode lock (e.g. btrfs, f2fs, ubifs ...) will have this problem, while filesystems with inode lock (e.g. xfs, nfs) won't have this problem. Link: https://lkml.kernel.org/r/20231213062324.739009-1-libaokun1@huawei.com Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: yangerkun <yangerkun@huawei.com> Cc: Yu Kuai <yukuai3@huawei.com> Cc: Zhang Yi <yi.zhang@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Li zeming
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a1748f85be |
mm: filemap: remove unnecessary iitialization of ret
The ret variable can be defined without assigning a value, as it is assigned before use. Link: https://lkml.kernel.org/r/20231205022954.101045-1-zeming@nfschina.com Signed-off-by: Li zeming <zeming@nfschina.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Minjie Du
|
8ff252663d |
mm/filemap: increase usage of folio_next_index() helper
Simplify code pattern of 'folio->index + folio_nr_pages(folio)' by using the existing helper folio_next_index() in filemap_get_folios_contig(). Link: https://lkml.kernel.org/r/20231107024635.4512-1-duminjie@vivo.com Signed-off-by: Minjie Du <duminjie@vivo.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Hugh Dickins
|
9aa1345d66 |
mm: fix oops when filemap_map_pmd() without prealloc_pte
syzbot reports oops in lockdep's __lock_acquire(), called from
__pte_offset_map_lock() called from filemap_map_pages(); or when I run the
repro, the oops comes in pmd_install(), called from filemap_map_pmd()
called from filemap_map_pages(), just before the __pte_offset_map_lock().
The problem is that filemap_map_pmd() has been assuming that when it finds
pmd_none(), a page table has already been prepared in prealloc_pte; and
indeed do_fault_around() has been careful to preallocate one there, when
it finds pmd_none(): but what if *pmd became none in between?
My 6.6 mods in mm/khugepaged.c, avoiding mmap_lock for write, have made it
easy for *pmd to be cleared while servicing a page fault; but even before
those, a huge *pmd might be zapped while a fault is serviced.
The difference in symptomatic stack traces comes from the "memory model"
in use: pmd_install() uses pmd_populate() uses page_to_pfn(): in some
models that is strict, and will oops on the NULL prealloc_pte; in other
models, it will construct a bogus value to be populated into *pmd, then
__pte_offset_map_lock() oops when trying to access split ptlock pointer
(or some other symptom in normal case of ptlock embedded not pointer).
Link: https://lore.kernel.org/linux-mm/20231115065506.19780-1-jose.pekkarinen@foxhound.fi/
Link: https://lkml.kernel.org/r/6ed0c50c-78ef-0719-b3c5-60c0c010431c@google.com
Fixes:
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Ryan Roberts
|
afccb0804f |
mm: more ptep_get() conversion
Commit
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Lorenzo Stoakes
|
e8e17ee90e |
mm: drop the assumption that VM_SHARED always implies writable
Patch series "permit write-sealed memfd read-only shared mappings", v4. The man page for fcntl() describing memfd file seals states the following about F_SEAL_WRITE:- Furthermore, trying to create new shared, writable memory-mappings via mmap(2) will also fail with EPERM. With emphasis on 'writable'. In turns out in fact that currently the kernel simply disallows all new shared memory mappings for a memfd with F_SEAL_WRITE applied, rendering this documentation inaccurate. This matters because users are therefore unable to obtain a shared mapping to a memfd after write sealing altogether, which limits their usefulness. This was reported in the discussion thread [1] originating from a bug report [2]. This is a product of both using the struct address_space->i_mmap_writable atomic counter to determine whether writing may be permitted, and the kernel adjusting this counter when any VM_SHARED mapping is performed and more generally implicitly assuming VM_SHARED implies writable. It seems sensible that we should only update this mapping if VM_MAYWRITE is specified, i.e. whether it is possible that this mapping could at any point be written to. If we do so then all we need to do to permit write seals to function as documented is to clear VM_MAYWRITE when mapping read-only. It turns out this functionality already exists for F_SEAL_FUTURE_WRITE - we can therefore simply adapt this logic to do the same for F_SEAL_WRITE. We then hit a chicken and egg situation in mmap_region() where the check for VM_MAYWRITE occurs before we are able to clear this flag. To work around this, perform this check after we invoke call_mmap(), with careful consideration of error paths. Thanks to Andy Lutomirski for the suggestion! [1]:https://lore.kernel.org/all/20230324133646.16101dfa666f253c4715d965@linux-foundation.org/ [2]:https://bugzilla.kernel.org/show_bug.cgi?id=217238 This patch (of 3): There is a general assumption that VMAs with the VM_SHARED flag set are writable. If the VM_MAYWRITE flag is not set, then this is simply not the case. Update those checks which affect the struct address_space->i_mmap_writable field to explicitly test for this by introducing [vma_]is_shared_maywrite() helper functions. This remains entirely conservative, as the lack of VM_MAYWRITE guarantees that the VMA cannot be written to. Link: https://lkml.kernel.org/r/cover.1697116581.git.lstoakes@gmail.com Link: https://lkml.kernel.org/r/d978aefefa83ec42d18dfa964ad180dbcde34795.1697116581.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
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b0b598ee08 |
filemap: remove use of wait bookmarks
The original problem of the overly long list of waiters on a locked page
was solved properly by commit
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Nhat Pham
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85ce2c517a |
memcontrol: only transfer the memcg data for migration
For most migration use cases, only transfer the memcg data from the old folio to the new folio, and clear the old folio's memcg data. No charging and uncharging will be done. This shaves off some work on the migration path, and avoids the temporary double charging of a folio during its migration. The only exception is replace_page_cache_folio(), which will use the old mem_cgroup_migrate() (now renamed to mem_cgroup_replace_folio). In that context, the isolation of the old page isn't quite as thorough as with migration, so we cannot use our new implementation directly. This patch is the result of the following discussion on the new hugetlb memcg accounting behavior: https://lore.kernel.org/lkml/20231003171329.GB314430@monkey/ Link: https://lkml.kernel.org/r/20231006184629.155543-3-nphamcs@gmail.com Signed-off-by: Nhat Pham <nphamcs@gmail.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Frank van der Linden <fvdl@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeelb@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Tejun heo <tj@kernel.org> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
2580d55458 |
mm: use folio_xor_flags_has_waiters() in folio_end_writeback()
Match how folio_unlock() works by combining the test for PG_waiters with the clearing of PG_writeback. This should have a small performance win, and removes the last user of folio_wake(). Link: https://lkml.kernel.org/r/20231004165317.1061855-18-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
7d0795d098 |
mm: make __end_folio_writeback() return void
Rather than check the result of test-and-clear, just check that we have the writeback bit set at the start. This wouldn't catch every case, but it's good enough (and enables the next patch). Link: https://lkml.kernel.org/r/20231004165317.1061855-17-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
0410cd844e |
mm: add folio_xor_flags_has_waiters()
Optimise folio_end_read() by setting the uptodate bit at the same time we clear the unlock bit. This saves at least one memory barrier and one write-after-write hazard. Link: https://lkml.kernel.org/r/20231004165317.1061855-16-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
f12fb73b74 |
mm: delete checks for xor_unlock_is_negative_byte()
Architectures which don't define their own use the one in asm-generic/bitops/lock.h. Get rid of all the ifdefs around "maybe we don't have it". Link: https://lkml.kernel.org/r/20231004165317.1061855-15-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
247dbcdbf7 |
bitops: add xor_unlock_is_negative_byte()
Replace clear_bit_and_unlock_is_negative_byte() with xor_unlock_is_negative_byte(). We have a few places that like to lock a folio, set a flag and unlock it again. Allow for the possibility of combining the latter two operations for efficiency. We are guaranteed that the caller holds the lock, so it is safe to unlock it with the xor. The caller must guarantee that nobody else will set the flag without holding the lock; it is not safe to do this with the PG_dirty flag, for example. Link: https://lkml.kernel.org/r/20231004165317.1061855-8-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
0b237047d5 |
mm: add folio_end_read()
Provide a function for filesystems to call when they have finished reading an entire folio. Link: https://lkml.kernel.org/r/20231004165317.1061855-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Pankaj Raghav
|
bafd7e9d35 |
filemap: call filemap_get_folios_tag() from filemap_get_folios()
filemap_get_folios() is filemap_get_folios_tag() with XA_PRESENT as the tag that is being matched. Return filemap_get_folios_tag() with XA_PRESENT as the tag instead of duplicating the code in filemap_get_folios(). No functional changes. Link: https://lkml.kernel.org/r/20231006110120.136809-1-kernel@pankajraghav.com Signed-off-by: Pankaj Raghav <p.raghav@samsung.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
5d74b2ab2c |
mm: make lock_folio_maybe_drop_mmap() VMA lock aware
Patch series "Handle more faults under the VMA lock", v2. At this point, we're handling the majority of file-backed page faults under the VMA lock, using the ->map_pages entry point. This patch set attempts to expand that for the following siutations: - We have to do a read. This could be because we've hit the point in the readahead window where we need to kick off the next readahead, or because the page is simply not present in cache. - We're handling a write fault. Most applications don't do I/O by writes to shared mmaps for very good reasons, but some do, and it'd be nice to not make that slow unnecessarily. - We're doing a COW of a private mapping (both PTE already present and PTE not-present). These are two different codepaths and I handle both of them in this patch set. There is no support in this patch set for drivers to mark themselves as being VMA lock friendly; they could implement the ->map_pages vm_operation, but if they do, they would be the first. This is probably something we want to change at some point in the future, and I've marked where to make that change in the code. There is very little performance change in the benchmarks we've run; mostly because the vast majority of page faults are handled through the other paths. I still think this patch series is useful for workloads that may take these paths more often, and just for cleaning up the fault path in general (it's now clearer why we have to retry in these cases). This patch (of 6): Drop the VMA lock instead of the mmap_lock if that's the one which is held. Link: https://lkml.kernel.org/r/20231006195318.4087158-1-willy@infradead.org Link: https://lkml.kernel.org/r/20231006195318.4087158-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Lorenzo Stoakes
|
6facf36ee4 |
mm/filemap: clarify filemap_fault() comments for not uptodate case
The existing comments in filemap_fault() suggest that, after either a minor fault has occurred and filemap_get_folio() found a folio in the page cache, or a major fault arose and __filemap_get_folio(FGP_CREATE...) did the job (having relied on do_sync_mmap_readahead() or filemap_read_folio() to read in the folio), the only possible reason it could not be uptodate is because of an error. This is not so, as if, for instance, the fault occurred within a VMA which had the VM_RAND_READ flag set (via madvise() with the MADV_RANDOM flag specified), this would cause even synchronous readahead to fail to read in the folio. I confirmed this by dropping page caches and faulting in memory madvise()'d this way, observing that this code path was reached on each occasion. Clarify the comments to include this case, and additionally update the comment recently added around the invalidate lock logic to make it clear the comment explicitly refers to the minor fault case. In addition, while we're here, refer to folios rather than pages. [lstoakes@gmail.com: correct identation as per Christopher's feedback] Link: https://lkml.kernel.org/r/2c7014c0-6343-4e76-8697-3f84f54350bd@lucifer.local Link: https://lkml.kernel.org/r/20230930231029.88196-1-lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Sidhartha Kumar
|
a08c7193e4 |
mm/filemap: remove hugetlb special casing in filemap.c
Remove special cased hugetlb handling code within the page cache by changing the granularity of ->index to the base page size rather than the huge page size. The motivation of this patch is to reduce complexity within the filemap code while also increasing performance by removing branches that are evaluated on every page cache lookup. To support the change in index, new wrappers for hugetlb page cache interactions are added. These wrappers perform the conversion to a linear index which is now expected by the page cache for huge pages. ========================= PERFORMANCE ====================================== Perf was used to check the performance differences after the patch. Overall the performance is similar to mainline with a very small larger overhead that occurs in __filemap_add_folio() and hugetlb_add_to_page_cache(). This is because of the larger overhead that occurs in xa_load() and xa_store() as the xarray is now using more entries to store hugetlb folios in the page cache. Timing aarch64 2MB Page Size 6.5-rc3 + this patch: [root@sidhakum-ol9-1 hugepages]# time fallocate -l 700GB test.txt real 1m49.568s user 0m0.000s sys 1m49.461s 6.5-rc3: [root]# time fallocate -l 700GB test.txt real 1m47.495s user 0m0.000s sys 1m47.370s 1GB Page Size 6.5-rc3 + this patch: [root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt real 1m47.024s user 0m0.000s sys 1m46.921s 6.5-rc3: [root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt real 1m44.551s user 0m0.000s sys 1m44.438s x86 2MB Page Size 6.5-rc3 + this patch: [root@sidhakum-ol9-2 hugepages]# time fallocate -l 100GB test.txt real 0m22.383s user 0m0.000s sys 0m22.255s 6.5-rc3: [opc@sidhakum-ol9-2 hugepages]$ time sudo fallocate -l 100GB /dev/hugepages/test.txt real 0m22.735s user 0m0.038s sys 0m22.567s 1GB Page Size 6.5-rc3 + this patch: [root@sidhakum-ol9-2 hugepages1GB]# time fallocate -l 100GB test.txt real 0m25.786s user 0m0.001s sys 0m25.589s 6.5-rc3: [root@sidhakum-ol9-2 hugepages1G]# time fallocate -l 100GB test.txt real 0m33.454s user 0m0.001s sys 0m33.193s aarch64: workload - fallocate a 700GB file backed by huge pages 6.5-rc3 + this patch: 2MB Page Size: --100.00%--__arm64_sys_fallocate ksys_fallocate vfs_fallocate hugetlbfs_fallocate | |--95.04%--__pi_clear_page | |--3.57%--clear_huge_page | | | |--2.63%--rcu_all_qs | | | --0.91%--__cond_resched | --0.67%--__cond_resched 0.17% 0.00% 0 fallocate [kernel.vmlinux] [k] hugetlb_add_to_page_cache 0.14% 0.10% 11 fallocate [kernel.vmlinux] [k] __filemap_add_folio 6.5-rc3 2MB Page Size: --100.00%--__arm64_sys_fallocate ksys_fallocate vfs_fallocate hugetlbfs_fallocate | |--94.91%--__pi_clear_page | |--4.11%--clear_huge_page | | | |--3.00%--rcu_all_qs | | | --1.10%--__cond_resched | --0.59%--__cond_resched 0.08% 0.01% 1 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache 0.05% 0.03% 3 fallocate [kernel.kallsyms] [k] __filemap_add_folio x86 workload - fallocate a 100GB file backed by huge pages 6.5-rc3 + this patch: 2MB Page Size: hugetlbfs_fallocate | --99.57%--clear_huge_page | --98.47%--clear_page_erms | --0.53%--asm_sysvec_apic_timer_interrupt 0.04% 0.04% 1 fallocate [kernel.kallsyms] [k] xa_load 0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache 0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] __filemap_add_folio 0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] xas_store 6.5-rc3 2MB Page Size: --99.93%--__x64_sys_fallocate vfs_fallocate hugetlbfs_fallocate | --99.38%--clear_huge_page | |--98.40%--clear_page_erms | --0.59%--__cond_resched 0.03% 0.03% 1 fallocate [kernel.kallsyms] [k] __filemap_add_folio ========================= TESTING ====================================== This patch passes libhugetlbfs tests and LTP hugetlb tests ********** TEST SUMMARY * 2M * 32-bit 64-bit * Total testcases: 110 113 * Skipped: 0 0 * PASS: 107 113 * FAIL: 0 0 * Killed by signal: 3 0 * Bad configuration: 0 0 * Expected FAIL: 0 0 * Unexpected PASS: 0 0 * Test not present: 0 0 * Strange test result: 0 0 ********** Done executing testcases. LTP Version: 20220527-178-g2761a81c4 page migration was also tested using Mike Kravetz's test program.[8] [dan.carpenter@linaro.org: fix an NULL vs IS_ERR() bug] Link: https://lkml.kernel.org/r/1772c296-1417-486f-8eef-171af2192681@moroto.mountain Link: https://lkml.kernel.org/r/20230926192017.98183-1-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Reported-and-tested-by: syzbot+c225dea486da4d5592bd@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=c225dea486da4d5592bd Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Minjie Du
|
d98388cef5 |
mm/filemap: increase usage of folio_next_index() helper
Simplify code pattern of 'folio->index + folio_nr_pages(folio)' by using the existing helper folio_next_index() in filemap_map_pages(). Link: https://lkml.kernel.org/r/20230921081535.3398-1-duminjie@vivo.com Signed-off-by: Minjie Du <duminjie@vivo.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
a501a07030 |
mm: report success more often from filemap_map_folio_range()
Even though we had successfully mapped the relevant page, we would rarely
return success from filemap_map_folio_range(). That leads to falling back
from the VMA lock path to the mmap_lock path, which is a speed &
scalability issue. Found by inspection.
Link: https://lkml.kernel.org/r/20230920035336.854212-1-willy@infradead.org
Fixes:
|
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Yin Fengwei
|
c8be038067 |
filemap: add filemap_map_order0_folio() to handle order0 folio
Kernel test robot reported regressions for several benchmarks [1]. The regression are related with commit: |
||
Tong Tiangen
|
d256d1cd8d |
mm: memory-failure: use rcu lock instead of tasklist_lock when collect_procs()
We found a softlock issue in our test, analyzed the logs, and found that the relevant CPU call trace as follows: CPU0: _do_fork -> copy_process() -> write_lock_irq(&tasklist_lock) //Disable irq,waiting for //tasklist_lock CPU1: wp_page_copy() ->pte_offset_map_lock() -> spin_lock(&page->ptl); //Hold page->ptl -> ptep_clear_flush() -> flush_tlb_others() ... -> smp_call_function_many() -> arch_send_call_function_ipi_mask() -> csd_lock_wait() //Waiting for other CPUs respond //IPI CPU2: collect_procs_anon() -> read_lock(&tasklist_lock) //Hold tasklist_lock ->for_each_process(tsk) -> page_mapped_in_vma() -> page_vma_mapped_walk() -> map_pte() ->spin_lock(&page->ptl) //Waiting for page->ptl We can see that CPU1 waiting for CPU0 respond IPI,CPU0 waiting for CPU2 unlock tasklist_lock, CPU2 waiting for CPU1 unlock page->ptl. As a result, softlockup is triggered. For collect_procs_anon(), what we're doing is task list iteration, during the iteration, with the help of call_rcu(), the task_struct object is freed only after one or more grace periods elapse. the logic as follows: release_task() -> __exit_signal() -> __unhash_process() -> list_del_rcu() -> put_task_struct_rcu_user() -> call_rcu(&task->rcu, delayed_put_task_struct) delayed_put_task_struct() -> put_task_struct() -> if (refcount_sub_and_test()) __put_task_struct() -> free_task() Therefore, under the protection of the rcu lock, we can safely use get_task_struct() to ensure a safe reference to task_struct during the iteration. By removing the use of tasklist_lock in task list iteration, we can break the softlock chain above. The same logic can also be applied to: - collect_procs_file() - collect_procs_fsdax() - collect_procs_ksm() Link: https://lkml.kernel.org/r/20230828022527.241693-1-tongtiangen@huawei.com Signed-off-by: Tong Tiangen <tongtiangen@huawei.com> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Linus Torvalds
|
b96a3e9142 |
- Some swap cleanups from Ma Wupeng ("fix WARN_ON in add_to_avail_list")
- Peter Xu has a series (mm/gup: Unify hugetlb, speed up thp") which reduces the special-case code for handling hugetlb pages in GUP. It also speeds up GUP handling of transparent hugepages. - Peng Zhang provides some maple tree speedups ("Optimize the fast path of mas_store()"). - Sergey Senozhatsky has improved te performance of zsmalloc during compaction (zsmalloc: small compaction improvements"). - Domenico Cerasuolo has developed additional selftest code for zswap ("selftests: cgroup: add zswap test program"). - xu xin has doe some work on KSM's handling of zero pages. These changes are mainly to enable the user to better understand the effectiveness of KSM's treatment of zero pages ("ksm: support tracking KSM-placed zero-pages"). - Jeff Xu has fixes the behaviour of memfd's MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED sysctl ("mm/memfd: fix sysctl MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED"). - David Howells has fixed an fscache optimization ("mm, netfs, fscache: Stop read optimisation when folio removed from pagecache"). - Axel Rasmussen has given userfaultfd the ability to simulate memory poisoning ("add UFFDIO_POISON to simulate memory poisoning with UFFD"). - Miaohe Lin has contributed some routine maintenance work on the memory-failure code ("mm: memory-failure: remove unneeded PageHuge() check"). - Peng Zhang has contributed some maintenance work on the maple tree code ("Improve the validation for maple tree and some cleanup"). - Hugh Dickins has optimized the collapsing of shmem or file pages into THPs ("mm: free retracted page table by RCU"). - Jiaqi Yan has a patch series which permits us to use the healthy subpages within a hardware poisoned huge page for general purposes ("Improve hugetlbfs read on HWPOISON hugepages"). - Kemeng Shi has done some maintenance work on the pagetable-check code ("Remove unused parameters in page_table_check"). - More folioification work from Matthew Wilcox ("More filesystem folio conversions for 6.6"), ("Followup folio conversions for zswap"). And from ZhangPeng ("Convert several functions in page_io.c to use a folio"). - page_ext cleanups from Kemeng Shi ("minor cleanups for page_ext"). - Baoquan He has converted some architectures to use the GENERIC_IOREMAP ioremap()/iounmap() code ("mm: ioremap: Convert architectures to take GENERIC_IOREMAP way"). - Anshuman Khandual has optimized arm64 tlb shootdown ("arm64: support batched/deferred tlb shootdown during page reclamation/migration"). - Better maple tree lockdep checking from Liam Howlett ("More strict maple tree lockdep"). Liam also developed some efficiency improvements ("Reduce preallocations for maple tree"). - Cleanup and optimization to the secondary IOMMU TLB invalidation, from Alistair Popple ("Invalidate secondary IOMMU TLB on permission upgrade"). - Ryan Roberts fixes some arm64 MM selftest issues ("selftests/mm fixes for arm64"). - Kemeng Shi provides some maintenance work on the compaction code ("Two minor cleanups for compaction"). - Some reduction in mmap_lock pressure from Matthew Wilcox ("Handle most file-backed faults under the VMA lock"). - Aneesh Kumar contributes code to use the vmemmap optimization for DAX on ppc64, under some circumstances ("Add support for DAX vmemmap optimization for ppc64"). - page-ext cleanups from Kemeng Shi ("add page_ext_data to get client data in page_ext"), ("minor cleanups to page_ext header"). - Some zswap cleanups from Johannes Weiner ("mm: zswap: three cleanups"). - kmsan cleanups from ZhangPeng ("minor cleanups for kmsan"). - VMA handling cleanups from Kefeng Wang ("mm: convert to vma_is_initial_heap/stack()"). - DAMON feature work from SeongJae Park ("mm/damon/sysfs-schemes: implement DAMOS tried total bytes file"), ("Extend DAMOS filters for address ranges and DAMON monitoring targets"). - Compaction work from Kemeng Shi ("Fixes and cleanups to compaction"). - Liam Howlett has improved the maple tree node replacement code ("maple_tree: Change replacement strategy"). - ZhangPeng has a general code cleanup - use the K() macro more widely ("cleanup with helper macro K()"). - Aneesh Kumar brings memmap-on-memory to ppc64 ("Add support for memmap on memory feature on ppc64"). - pagealloc cleanups from Kemeng Shi ("Two minor cleanups for pcp list in page_alloc"), ("Two minor cleanups for get pageblock migratetype"). - Vishal Moola introduces a memory descriptor for page table tracking, "struct ptdesc" ("Split ptdesc from struct page"). - memfd selftest maintenance work from Aleksa Sarai ("memfd: cleanups for vm.memfd_noexec"). - MM include file rationalization from Hugh Dickins ("arch: include asm/cacheflush.h in asm/hugetlb.h"). - THP debug output fixes from Hugh Dickins ("mm,thp: fix sloppy text output"). - kmemleak improvements from Xiaolei Wang ("mm/kmemleak: use object_cache instead of kmemleak_initialized"). - More folio-related cleanups from Matthew Wilcox ("Remove _folio_dtor and _folio_order"). - A VMA locking scalability improvement from Suren Baghdasaryan ("Per-VMA lock support for swap and userfaults"). - pagetable handling cleanups from Matthew Wilcox ("New page table range API"). - A batch of swap/thp cleanups from David Hildenbrand ("mm/swap: stop using page->private on tail pages for THP_SWAP + cleanups"). - Cleanups and speedups to the hugetlb fault handling from Matthew Wilcox ("Change calling convention for ->huge_fault"). - Matthew Wilcox has also done some maintenance work on the MM subsystem documentation ("Improve mm documentation"). -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZO1JUQAKCRDdBJ7gKXxA jrMwAP47r/fS8vAVT3zp/7fXmxaJYTK27CTAM881Gw1SDhFM/wEAv8o84mDenCg6 Nfio7afS1ncD+hPYT8947UnLxTgn+ww= =Afws -----END PGP SIGNATURE----- Merge tag 'mm-stable-2023-08-28-18-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Some swap cleanups from Ma Wupeng ("fix WARN_ON in add_to_avail_list") - Peter Xu has a series (mm/gup: Unify hugetlb, speed up thp") which reduces the special-case code for handling hugetlb pages in GUP. It also speeds up GUP handling of transparent hugepages. - Peng Zhang provides some maple tree speedups ("Optimize the fast path of mas_store()"). - Sergey Senozhatsky has improved te performance of zsmalloc during compaction (zsmalloc: small compaction improvements"). - Domenico Cerasuolo has developed additional selftest code for zswap ("selftests: cgroup: add zswap test program"). - xu xin has doe some work on KSM's handling of zero pages. These changes are mainly to enable the user to better understand the effectiveness of KSM's treatment of zero pages ("ksm: support tracking KSM-placed zero-pages"). - Jeff Xu has fixes the behaviour of memfd's MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED sysctl ("mm/memfd: fix sysctl MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED"). - David Howells has fixed an fscache optimization ("mm, netfs, fscache: Stop read optimisation when folio removed from pagecache"). - Axel Rasmussen has given userfaultfd the ability to simulate memory poisoning ("add UFFDIO_POISON to simulate memory poisoning with UFFD"). - Miaohe Lin has contributed some routine maintenance work on the memory-failure code ("mm: memory-failure: remove unneeded PageHuge() check"). - Peng Zhang has contributed some maintenance work on the maple tree code ("Improve the validation for maple tree and some cleanup"). - Hugh Dickins has optimized the collapsing of shmem or file pages into THPs ("mm: free retracted page table by RCU"). - Jiaqi Yan has a patch series which permits us to use the healthy subpages within a hardware poisoned huge page for general purposes ("Improve hugetlbfs read on HWPOISON hugepages"). - Kemeng Shi has done some maintenance work on the pagetable-check code ("Remove unused parameters in page_table_check"). - More folioification work from Matthew Wilcox ("More filesystem folio conversions for 6.6"), ("Followup folio conversions for zswap"). And from ZhangPeng ("Convert several functions in page_io.c to use a folio"). - page_ext cleanups from Kemeng Shi ("minor cleanups for page_ext"). - Baoquan He has converted some architectures to use the GENERIC_IOREMAP ioremap()/iounmap() code ("mm: ioremap: Convert architectures to take GENERIC_IOREMAP way"). - Anshuman Khandual has optimized arm64 tlb shootdown ("arm64: support batched/deferred tlb shootdown during page reclamation/migration"). - Better maple tree lockdep checking from Liam Howlett ("More strict maple tree lockdep"). Liam also developed some efficiency improvements ("Reduce preallocations for maple tree"). - Cleanup and optimization to the secondary IOMMU TLB invalidation, from Alistair Popple ("Invalidate secondary IOMMU TLB on permission upgrade"). - Ryan Roberts fixes some arm64 MM selftest issues ("selftests/mm fixes for arm64"). - Kemeng Shi provides some maintenance work on the compaction code ("Two minor cleanups for compaction"). - Some reduction in mmap_lock pressure from Matthew Wilcox ("Handle most file-backed faults under the VMA lock"). - Aneesh Kumar contributes code to use the vmemmap optimization for DAX on ppc64, under some circumstances ("Add support for DAX vmemmap optimization for ppc64"). - page-ext cleanups from Kemeng Shi ("add page_ext_data to get client data in page_ext"), ("minor cleanups to page_ext header"). - Some zswap cleanups from Johannes Weiner ("mm: zswap: three cleanups"). - kmsan cleanups from ZhangPeng ("minor cleanups for kmsan"). - VMA handling cleanups from Kefeng Wang ("mm: convert to vma_is_initial_heap/stack()"). - DAMON feature work from SeongJae Park ("mm/damon/sysfs-schemes: implement DAMOS tried total bytes file"), ("Extend DAMOS filters for address ranges and DAMON monitoring targets"). - Compaction work from Kemeng Shi ("Fixes and cleanups to compaction"). - Liam Howlett has improved the maple tree node replacement code ("maple_tree: Change replacement strategy"). - ZhangPeng has a general code cleanup - use the K() macro more widely ("cleanup with helper macro K()"). - Aneesh Kumar brings memmap-on-memory to ppc64 ("Add support for memmap on memory feature on ppc64"). - pagealloc cleanups from Kemeng Shi ("Two minor cleanups for pcp list in page_alloc"), ("Two minor cleanups for get pageblock migratetype"). - Vishal Moola introduces a memory descriptor for page table tracking, "struct ptdesc" ("Split ptdesc from struct page"). - memfd selftest maintenance work from Aleksa Sarai ("memfd: cleanups for vm.memfd_noexec"). - MM include file rationalization from Hugh Dickins ("arch: include asm/cacheflush.h in asm/hugetlb.h"). - THP debug output fixes from Hugh Dickins ("mm,thp: fix sloppy text output"). - kmemleak improvements from Xiaolei Wang ("mm/kmemleak: use object_cache instead of kmemleak_initialized"). - More folio-related cleanups from Matthew Wilcox ("Remove _folio_dtor and _folio_order"). - A VMA locking scalability improvement from Suren Baghdasaryan ("Per-VMA lock support for swap and userfaults"). - pagetable handling cleanups from Matthew Wilcox ("New page table range API"). - A batch of swap/thp cleanups from David Hildenbrand ("mm/swap: stop using page->private on tail pages for THP_SWAP + cleanups"). - Cleanups and speedups to the hugetlb fault handling from Matthew Wilcox ("Change calling convention for ->huge_fault"). - Matthew Wilcox has also done some maintenance work on the MM subsystem documentation ("Improve mm documentation"). * tag 'mm-stable-2023-08-28-18-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (489 commits) maple_tree: shrink struct maple_tree maple_tree: clean up mas_wr_append() secretmem: convert page_is_secretmem() to folio_is_secretmem() nios2: fix flush_dcache_page() for usage from irq context hugetlb: add documentation for vma_kernel_pagesize() mm: add orphaned kernel-doc to the rst files. mm: fix clean_record_shared_mapping_range kernel-doc mm: fix get_mctgt_type() kernel-doc mm: fix kernel-doc warning from tlb_flush_rmaps() mm: remove enum page_entry_size mm: allow ->huge_fault() to be called without the mmap_lock held mm: move PMD_ORDER to pgtable.h mm: remove checks for pte_index memcg: remove duplication detection for mem_cgroup_uncharge_swap mm/huge_memory: work on folio->swap instead of page->private when splitting folio mm/swap: inline folio_set_swap_entry() and folio_swap_entry() mm/swap: use dedicated entry for swap in folio mm/swap: stop using page->private on tail pages for THP_SWAP selftests/mm: fix WARNING comparing pointer to 0 selftests: cgroup: fix test_kmem_memcg_deletion kernel mem check ... |
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Yin Fengwei
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617c28ecab |
filemap: batch PTE mappings
Call set_pte_range() once per contiguous range of the folio instead of once per page. This batches the updates to mm counters and the rmap. With a will-it-scale.page_fault3 like app (change file write fault testing to read fault testing. Trying to upstream it to will-it-scale at [1]) got 15% performance gain on a 48C/96T Cascade Lake test box with 96 processes running against xfs. Perf data collected before/after the change: 18.73%--page_add_file_rmap | --11.60%--__mod_lruvec_page_state | |--7.40%--__mod_memcg_lruvec_state | | | --5.58%--cgroup_rstat_updated | --2.53%--__mod_lruvec_state | --1.48%--__mod_node_page_state 9.93%--page_add_file_rmap_range | --2.67%--__mod_lruvec_page_state | |--1.95%--__mod_memcg_lruvec_state | | | --1.57%--cgroup_rstat_updated | --0.61%--__mod_lruvec_state | --0.54%--__mod_node_page_state The running time of __mode_lruvec_page_state() is reduced about 9%. [1]: https://github.com/antonblanchard/will-it-scale/pull/37 Link: https://lkml.kernel.org/r/20230802151406.3735276-38-willy@infradead.org Signed-off-by: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Yin Fengwei
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3bd786f76d |
mm: convert do_set_pte() to set_pte_range()
set_pte_range() allows to setup page table entries for a specific range. It takes advantage of batched rmap update for large folio. It now takes care of calling update_mmu_cache_range(). Link: https://lkml.kernel.org/r/20230802151406.3735276-37-willy@infradead.org Signed-off-by: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Yin Fengwei
|
de74976eb6 |
filemap: add filemap_map_folio_range()
filemap_map_folio_range() maps partial/full folio. Comparing to original filemap_map_pages(), it updates refcount once per folio instead of per page and gets minor performance improvement for large folio. With a will-it-scale.page_fault3 like app (change file write fault testing to read fault testing. Trying to upstream it to will-it-scale at [1]), got 2% performance gain on a 48C/96T Cascade Lake test box with 96 processes running against xfs. [1]: https://github.com/antonblanchard/will-it-scale/pull/37 Link: https://lkml.kernel.org/r/20230802151406.3735276-35-willy@infradead.org Signed-off-by: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Suren Baghdasaryan
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1235ccd05b |
mm: handle swap page faults under per-VMA lock
When page fault is handled under per-VMA lock protection, all swap page faults are retried with mmap_lock because folio_lock_or_retry has to drop and reacquire mmap_lock if folio could not be immediately locked. Follow the same pattern as mmap_lock to drop per-VMA lock when waiting for folio and retrying once folio is available. With this obstacle removed, enable do_swap_page to operate under per-VMA lock protection. Drivers implementing ops->migrate_to_ram might still rely on mmap_lock, therefore we have to fall back to mmap_lock in that particular case. Note that the only time do_swap_page calls synchronous swap_readpage is when SWP_SYNCHRONOUS_IO is set, which is only set for QUEUE_FLAG_SYNCHRONOUS devices: brd, zram and nvdimms (both btt and pmem). Therefore we don't sleep in this path, and there's no need to drop the mmap or per-VMA lock. Link: https://lkml.kernel.org/r/20230630211957.1341547-6-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Tested-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: Alistair Popple <apopple@nvidia.com> Acked-by: Peter Xu <peterx@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hillf Danton <hdanton@sina.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Michel Lespinasse <michel@lespinasse.org> Cc: Minchan Kim <minchan@google.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Suren Baghdasaryan
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fdc724d6aa |
mm: change folio_lock_or_retry to use vm_fault directly
Change folio_lock_or_retry to accept vm_fault struct and return the vm_fault_t directly. Link: https://lkml.kernel.org/r/20230630211957.1341547-5-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Acked-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hillf Danton <hdanton@sina.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Michel Lespinasse <michel@lespinasse.org> Cc: Minchan Kim <minchan@google.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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David Howells
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0201ebf274 |
mm: merge folio_has_private()/filemap_release_folio() call pairs
Patch series "mm, netfs, fscache: Stop read optimisation when folio removed from pagecache", v7. This fixes an optimisation in fscache whereby we don't read from the cache for a particular file until we know that there's data there that we don't have in the pagecache. The problem is that I'm no longer using PG_fscache (aka PG_private_2) to indicate that the page is cached and so I don't get a notification when a cached page is dropped from the pagecache. The first patch merges some folio_has_private() and filemap_release_folio() pairs and introduces a helper, folio_needs_release(), to indicate if a release is required. The second patch is the actual fix. Following Willy's suggestions[1], it adds an AS_RELEASE_ALWAYS flag to an address_space that will make filemap_release_folio() always call ->release_folio(), even if PG_private/PG_private_2 aren't set. folio_needs_release() is altered to add a check for this. This patch (of 2): Make filemap_release_folio() check folio_has_private(). Then, in most cases, where a call to folio_has_private() is immediately followed by a call to filemap_release_folio(), we can get rid of the test in the pair. There are a couple of sites in mm/vscan.c that this can't so easily be done. In shrink_folio_list(), there are actually three cases (something different is done for incompletely invalidated buffers), but filemap_release_folio() elides two of them. In shrink_active_list(), we don't have have the folio lock yet, so the check allows us to avoid locking the page unnecessarily. A wrapper function to check if a folio needs release is provided for those places that still need to do it in the mm/ directory. This will acquire additional parts to the condition in a future patch. After this, the only remaining caller of folio_has_private() outside of mm/ is a check in fuse. Link: https://lkml.kernel.org/r/20230628104852.3391651-1-dhowells@redhat.com Link: https://lkml.kernel.org/r/20230628104852.3391651-2-dhowells@redhat.com Reported-by: Rohith Surabattula <rohiths.msft@gmail.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: David Howells <dhowells@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Steve French <sfrench@samba.org> Cc: Shyam Prasad N <nspmangalore@gmail.com> Cc: Rohith Surabattula <rohiths.msft@gmail.com> Cc: Dave Wysochanski <dwysocha@redhat.com> Cc: Dominique Martinet <asmadeus@codewreck.org> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Xiubo Li <xiubli@redhat.com> Cc: Jingbo Xu <jefflexu@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |