mirror of https://github.com/torvalds/linux.git
619 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Kemeng Shi
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8678d1faf1 |
mm: swap: remove stale comment stale comment in cluster_alloc_swap_entry()
As cluster_next_cpu was already dropped, the associated comment is stale now. Link: https://lkml.kernel.org/r/20250522122554.12209-5-shikemeng@huaweicloud.com Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Kairui Song <kasong@tencent.com> Reviewed-by: Baoquan He <bhe@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kemeng Shi
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152c1339dc |
mm: swap: fix potential buffer overflow in setup_clusters()
In setup_swap_map(), we only ensure badpages are in range (0, last_page].
As maxpages might be < last_page, setup_clusters() will encounter a buffer
overflow when a badpage is >= maxpages.
Only call inc_cluster_info_page() for badpage which is < maxpages to fix
the issue.
Link: https://lkml.kernel.org/r/20250522122554.12209-4-shikemeng@huaweicloud.com
Fixes:
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Kemeng Shi
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255116c5b0 |
mm: swap: correctly use maxpages in swapon syscall to avoid potential deadloop
We use maxpages from read_swap_header() to initialize swap_info_struct,
however the maxpages might be reduced in setup_swap_extents() and the
si->max is assigned with the reduced maxpages from the
setup_swap_extents().
Obviously, this could lead to memory waste as we allocated memory based on
larger maxpages, besides, this could lead to a potential deadloop as
following:
1) When calling setup_clusters() with larger maxpages, unavailable
pages within range [si->max, larger maxpages) are not accounted with
inc_cluster_info_page(). As a result, these pages are assumed
available but can not be allocated. The cluster contains these pages
can be moved to frag_clusters list after it's all available pages were
allocated.
2) When the cluster mentioned in 1) is the only cluster in
frag_clusters list, cluster_alloc_swap_entry() assume order 0
allocation will never failed and will enter a deadloop by keep trying
to allocate page from the only cluster in frag_clusters which contains
no actually available page.
Call setup_swap_extents() to get the final maxpages before
swap_info_struct initialization to fix the issue.
After this change, span will include badblocks and will become large
value which I think is correct value:
In summary, there are two kinds of swapfile_activate operations.
1. Filesystem style: Treat all blocks logical continuity and find
usable physical extents in logical range. In this way, si->pages will
be actual usable physical blocks and span will be "1 + highest_block -
lowest_block".
2. Block device style: Treat all blocks physically continue and only
one single extent is added. In this way, si->pages will be si->max and
span will be "si->pages - 1". Actually, si->pages and si->max is only
used in block device style and span value is set with si->pages. As a
result, span value in block device style will become a larger value as
you mentioned.
I think larger value is correct based on:
1. Span value in filesystem style is "1 + highest_block -
lowest_block" which is the range cover all possible phisical blocks
including the badblocks.
2. For block device style, si->pages is the actual usable block number
and is already in pr_info. The original span value before this patch
is also refer to usable block number which is redundant in pr_info.
[shikemeng@huaweicloud.com: ensure si->pages == si->max - 1 after setup_swap_extents()]
Link: https://lkml.kernel.org/r/20250522122554.12209-3-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20250718065139.61989-1-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20250522122554.12209-3-shikemeng@huaweicloud.com
Fixes:
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Kemeng Shi
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4f78252da8 |
mm: swap: move nr_swap_pages counter decrement from folio_alloc_swap() to swap_range_alloc()
Patch series "Some randome fixes and cleanups to swapfile".
Patch 0-3 are some random fixes. Patch 4 is a cleanup. More details can
be found in respective patches.
This patch (of 4):
When folio_alloc_swap() encounters a failure in either
mem_cgroup_try_charge_swap() or add_to_swap_cache(), nr_swap_pages counter
is not decremented for allocated entry. However, the following
put_swap_folio() will increase nr_swap_pages counter unpairly and lead to
an imbalance.
Move nr_swap_pages decrement from folio_alloc_swap() to swap_range_alloc()
to pair the nr_swap_pages counting.
Link: https://lkml.kernel.org/r/20250522122554.12209-1-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20250522122554.12209-2-shikemeng@huaweicloud.com
Fixes:
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Linus Torvalds
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00c010e130 |
- The 11 patch series "Add folio_mk_pte()" from Matthew Wilcox
simplifies the act of creating a pte which addresses the first page in a folio and reduces the amount of plumbing which architecture must implement to provide this. - The 8 patch series "Misc folio patches for 6.16" from Matthew Wilcox is a shower of largely unrelated folio infrastructure changes which clean things up and better prepare us for future work. - The 3 patch series "memory,x86,acpi: hotplug memory alignment advisement" from Gregory Price adds early-init code to prevent x86 from leaving physical memory unused when physical address regions are not aligned to memory block size. - The 2 patch series "mm/compaction: allow more aggressive proactive compaction" from Michal Clapinski provides some tuning of the (sadly, hard-coded (more sadly, not auto-tuned)) thresholds for our invokation of proactive compaction. In a simple test case, the reduction of a guest VM's memory consumption was dramatic. - The 8 patch series "Minor cleanups and improvements to swap freeing code" from Kemeng Shi provides some code cleaups and a small efficiency improvement to this part of our swap handling code. - The 6 patch series "ptrace: introduce PTRACE_SET_SYSCALL_INFO API" from Dmitry Levin adds the ability for a ptracer to modify syscalls arguments. At this time we can alter only "system call information that are used by strace system call tampering, namely, syscall number, syscall arguments, and syscall return value. This series should have been incorporated into mm.git's "non-MM" branch, but I goofed. - The 3 patch series "fs/proc: extend the PAGEMAP_SCAN ioctl to report guard regions" from Andrei Vagin extends the info returned by the PAGEMAP_SCAN ioctl against /proc/pid/pagemap. This permits CRIU to more efficiently get at the info about guard regions. - The 2 patch series "Fix parameter passed to page_mapcount_is_type()" from Gavin Shan implements that fix. No runtime effect is expected because validate_page_before_insert() happens to fix up this error. - The 3 patch series "kernel/events/uprobes: uprobe_write_opcode() rewrite" from David Hildenbrand basically brings uprobe text poking into the current decade. Remove a bunch of hand-rolled implementation in favor of using more current facilities. - The 3 patch series "mm/ptdump: Drop assumption that pxd_val() is u64" from Anshuman Khandual provides enhancements and generalizations to the pte dumping code. This might be needed when 128-bit Page Table Descriptors are enabled for ARM. - The 12 patch series "Always call constructor for kernel page tables" from Kevin Brodsky "ensures that the ctor/dtor is always called for kernel pgtables, as it already is for user pgtables". This permits the addition of more functionality such as "insert hooks to protect page tables". This change does result in various architectures performing unnecesary work, but this is fixed up where it is anticipated to occur. - The 9 patch series "Rust support for mm_struct, vm_area_struct, and mmap" from Alice Ryhl adds plumbing to permit Rust access to core MM structures. - The 3 patch series "fix incorrectly disallowed anonymous VMA merges" from Lorenzo Stoakes takes advantage of some VMA merging opportunities which we've been missing for 15 years. - The 4 patch series "mm/madvise: batch tlb flushes for MADV_DONTNEED and MADV_FREE" from SeongJae Park optimizes process_madvise()'s TLB flushing. Instead of flushing each address range in the provided iovec, we batch the flushing across all the iovec entries. The syscall's cost was approximately halved with a microbenchmark which was designed to load this particular operation. - The 6 patch series "Track node vacancy to reduce worst case allocation counts" from Sidhartha Kumar makes the maple tree smarter about its node preallocation. stress-ng mmap performance increased by single-digit percentages and the amount of unnecessarily preallocated memory was dramaticelly reduced. - The 3 patch series "mm/gup: Minor fix, cleanup and improvements" from Baoquan He removes a few unnecessary things which Baoquan noted when reading the code. - The 3 patch series ""Enhance sysfs handling for memory hotplug in weighted interleave" from Rakie Kim "enhances the weighted interleave policy in the memory management subsystem by improving sysfs handling, fixing memory leaks, and introducing dynamic sysfs updates for memory hotplug support". Fixes things on error paths which we are unlikely to hit. - The 7 patch series "mm/damon: auto-tune DAMOS for NUMA setups including tiered memory" from SeongJae Park introduces new DAMOS quota goal metrics which eliminate the manual tuning which is required when utilizing DAMON for memory tiering. - The 5 patch series "mm/vmalloc.c: code cleanup and improvements" from Baoquan He provides cleanups and small efficiency improvements which Baoquan found via code inspection. - The 2 patch series "vmscan: enforce mems_effective during demotion" from Gregory Price "changes reclaim to respect cpuset.mems_effective during demotion when possible". because "presently, reclaim explicitly ignores cpuset.mems_effective when demoting, which may cause the cpuset settings to violated." "This is useful for isolating workloads on a multi-tenant system from certain classes of memory more consistently." - The 2 patch series ""Clean up split_huge_pmd_locked() and remove unnecessary folio pointers" from Gavin Guo provides minor cleanups and efficiency gains in in the huge page splitting and migrating code. - The 3 patch series "Use kmem_cache for memcg alloc" from Huan Yang creates a slab cache for `struct mem_cgroup', yielding improved memory utilization. - The 4 patch series "add max arg to swappiness in memory.reclaim and lru_gen" from Zhongkun He adds a new "max" argument to the "swappiness=" argument for memory.reclaim MGLRU's lru_gen. This directs proactive reclaim to reclaim from only anon folios rather than file-backed folios. - The 17 patch series "kexec: introduce Kexec HandOver (KHO)" from Mike Rapoport is the first step on the path to permitting the kernel to maintain existing VMs while replacing the host kernel via file-based kexec. At this time only memblock's reserve_mem is preserved. - The 7 patch series "mm: Introduce for_each_valid_pfn()" from David Woodhouse provides and uses a smarter way of looping over a pfn range. By skipping ranges of invalid pfns. - The 2 patch series "sched/numa: Skip VMA scanning on memory pinned to one NUMA node via cpuset.mems" from Libo Chen removes a lot of pointless VMA scanning when a task is pinned a single NUMA mode. Dramatic performance benefits were seen in some real world cases. - The 2 patch series "JFS: Implement migrate_folio for jfs_metapage_aops" from Shivank Garg addresses a warning which occurs during memory compaction when using JFS. - The 4 patch series "move all VMA allocation, freeing and duplication logic to mm" from Lorenzo Stoakes moves some VMA code from kernel/fork.c into the more appropriate mm/vma.c. - The 6 patch series "mm, swap: clean up swap cache mapping helper" from Kairui Song provides code consolidation and cleanups related to the folio_index() function. - The 2 patch series "mm/gup: Cleanup memfd_pin_folios()" from Vishal Moola does that. - The 8 patch series "memcg: Fix test_memcg_min/low test failures" from Waiman Long addresses some bogus failures which are being reported by the test_memcontrol selftest. - The 3 patch series "eliminate mmap() retry merge, add .mmap_prepare hook" from Lorenzo Stoakes commences the deprecation of file_operations.mmap() in favor of the new file_operations.mmap_prepare(). The latter is more restrictive and prevents drivers from messing with things in ways which, amongst other problems, may defeat VMA merging. - The 4 patch series "memcg: decouple memcg and objcg stocks"" from Shakeel Butt decouples the per-cpu memcg charge cache from the objcg's one. This is a step along the way to making memcg and objcg charging NMI-safe, which is a BPF requirement. - The 6 patch series "mm/damon: minor fixups and improvements for code, tests, and documents" from SeongJae Park is "yet another batch of miscellaneous DAMON changes. Fix and improve minor problems in code, tests and documents." - The 7 patch series "memcg: make memcg stats irq safe" from Shakeel Butt converts memcg stats to be irq safe. Another step along the way to making memcg charging and stats updates NMI-safe, a BPF requirement. - The 4 patch series "Let unmap_hugepage_range() and several related functions take folio instead of page" from Fan Ni provides folio conversions in the hugetlb code. -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCaDt5qgAKCRDdBJ7gKXxA ju6XAP9nTiSfRz8Cz1n5LJZpFKEGzLpSihCYyR6P3o1L9oe3mwEAlZ5+XAwk2I5x Qqb/UGMEpilyre1PayQqOnct3aSL9Ao= =tYYm -----END PGP SIGNATURE----- Merge tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - "Add folio_mk_pte()" from Matthew Wilcox simplifies the act of creating a pte which addresses the first page in a folio and reduces the amount of plumbing which architecture must implement to provide this. - "Misc folio patches for 6.16" from Matthew Wilcox is a shower of largely unrelated folio infrastructure changes which clean things up and better prepare us for future work. - "memory,x86,acpi: hotplug memory alignment advisement" from Gregory Price adds early-init code to prevent x86 from leaving physical memory unused when physical address regions are not aligned to memory block size. - "mm/compaction: allow more aggressive proactive compaction" from Michal Clapinski provides some tuning of the (sadly, hard-coded (more sadly, not auto-tuned)) thresholds for our invokation of proactive compaction. In a simple test case, the reduction of a guest VM's memory consumption was dramatic. - "Minor cleanups and improvements to swap freeing code" from Kemeng Shi provides some code cleaups and a small efficiency improvement to this part of our swap handling code. - "ptrace: introduce PTRACE_SET_SYSCALL_INFO API" from Dmitry Levin adds the ability for a ptracer to modify syscalls arguments. At this time we can alter only "system call information that are used by strace system call tampering, namely, syscall number, syscall arguments, and syscall return value. This series should have been incorporated into mm.git's "non-MM" branch, but I goofed. - "fs/proc: extend the PAGEMAP_SCAN ioctl to report guard regions" from Andrei Vagin extends the info returned by the PAGEMAP_SCAN ioctl against /proc/pid/pagemap. This permits CRIU to more efficiently get at the info about guard regions. - "Fix parameter passed to page_mapcount_is_type()" from Gavin Shan implements that fix. No runtime effect is expected because validate_page_before_insert() happens to fix up this error. - "kernel/events/uprobes: uprobe_write_opcode() rewrite" from David Hildenbrand basically brings uprobe text poking into the current decade. Remove a bunch of hand-rolled implementation in favor of using more current facilities. - "mm/ptdump: Drop assumption that pxd_val() is u64" from Anshuman Khandual provides enhancements and generalizations to the pte dumping code. This might be needed when 128-bit Page Table Descriptors are enabled for ARM. - "Always call constructor for kernel page tables" from Kevin Brodsky ensures that the ctor/dtor is always called for kernel pgtables, as it already is for user pgtables. This permits the addition of more functionality such as "insert hooks to protect page tables". This change does result in various architectures performing unnecesary work, but this is fixed up where it is anticipated to occur. - "Rust support for mm_struct, vm_area_struct, and mmap" from Alice Ryhl adds plumbing to permit Rust access to core MM structures. - "fix incorrectly disallowed anonymous VMA merges" from Lorenzo Stoakes takes advantage of some VMA merging opportunities which we've been missing for 15 years. - "mm/madvise: batch tlb flushes for MADV_DONTNEED and MADV_FREE" from SeongJae Park optimizes process_madvise()'s TLB flushing. Instead of flushing each address range in the provided iovec, we batch the flushing across all the iovec entries. The syscall's cost was approximately halved with a microbenchmark which was designed to load this particular operation. - "Track node vacancy to reduce worst case allocation counts" from Sidhartha Kumar makes the maple tree smarter about its node preallocation. stress-ng mmap performance increased by single-digit percentages and the amount of unnecessarily preallocated memory was dramaticelly reduced. - "mm/gup: Minor fix, cleanup and improvements" from Baoquan He removes a few unnecessary things which Baoquan noted when reading the code. - ""Enhance sysfs handling for memory hotplug in weighted interleave" from Rakie Kim "enhances the weighted interleave policy in the memory management subsystem by improving sysfs handling, fixing memory leaks, and introducing dynamic sysfs updates for memory hotplug support". Fixes things on error paths which we are unlikely to hit. - "mm/damon: auto-tune DAMOS for NUMA setups including tiered memory" from SeongJae Park introduces new DAMOS quota goal metrics which eliminate the manual tuning which is required when utilizing DAMON for memory tiering. - "mm/vmalloc.c: code cleanup and improvements" from Baoquan He provides cleanups and small efficiency improvements which Baoquan found via code inspection. - "vmscan: enforce mems_effective during demotion" from Gregory Price changes reclaim to respect cpuset.mems_effective during demotion when possible. because presently, reclaim explicitly ignores cpuset.mems_effective when demoting, which may cause the cpuset settings to violated. This is useful for isolating workloads on a multi-tenant system from certain classes of memory more consistently. - "Clean up split_huge_pmd_locked() and remove unnecessary folio pointers" from Gavin Guo provides minor cleanups and efficiency gains in in the huge page splitting and migrating code. - "Use kmem_cache for memcg alloc" from Huan Yang creates a slab cache for `struct mem_cgroup', yielding improved memory utilization. - "add max arg to swappiness in memory.reclaim and lru_gen" from Zhongkun He adds a new "max" argument to the "swappiness=" argument for memory.reclaim MGLRU's lru_gen. This directs proactive reclaim to reclaim from only anon folios rather than file-backed folios. - "kexec: introduce Kexec HandOver (KHO)" from Mike Rapoport is the first step on the path to permitting the kernel to maintain existing VMs while replacing the host kernel via file-based kexec. At this time only memblock's reserve_mem is preserved. - "mm: Introduce for_each_valid_pfn()" from David Woodhouse provides and uses a smarter way of looping over a pfn range. By skipping ranges of invalid pfns. - "sched/numa: Skip VMA scanning on memory pinned to one NUMA node via cpuset.mems" from Libo Chen removes a lot of pointless VMA scanning when a task is pinned a single NUMA mode. Dramatic performance benefits were seen in some real world cases. - "JFS: Implement migrate_folio for jfs_metapage_aops" from Shivank Garg addresses a warning which occurs during memory compaction when using JFS. - "move all VMA allocation, freeing and duplication logic to mm" from Lorenzo Stoakes moves some VMA code from kernel/fork.c into the more appropriate mm/vma.c. - "mm, swap: clean up swap cache mapping helper" from Kairui Song provides code consolidation and cleanups related to the folio_index() function. - "mm/gup: Cleanup memfd_pin_folios()" from Vishal Moola does that. - "memcg: Fix test_memcg_min/low test failures" from Waiman Long addresses some bogus failures which are being reported by the test_memcontrol selftest. - "eliminate mmap() retry merge, add .mmap_prepare hook" from Lorenzo Stoakes commences the deprecation of file_operations.mmap() in favor of the new file_operations.mmap_prepare(). The latter is more restrictive and prevents drivers from messing with things in ways which, amongst other problems, may defeat VMA merging. - "memcg: decouple memcg and objcg stocks"" from Shakeel Butt decouples the per-cpu memcg charge cache from the objcg's one. This is a step along the way to making memcg and objcg charging NMI-safe, which is a BPF requirement. - "mm/damon: minor fixups and improvements for code, tests, and documents" from SeongJae Park is yet another batch of miscellaneous DAMON changes. Fix and improve minor problems in code, tests and documents. - "memcg: make memcg stats irq safe" from Shakeel Butt converts memcg stats to be irq safe. Another step along the way to making memcg charging and stats updates NMI-safe, a BPF requirement. - "Let unmap_hugepage_range() and several related functions take folio instead of page" from Fan Ni provides folio conversions in the hugetlb code. * tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (285 commits) mm: pcp: increase pcp->free_count threshold to trigger free_high mm/hugetlb: convert use of struct page to folio in __unmap_hugepage_range() mm/hugetlb: refactor __unmap_hugepage_range() to take folio instead of page mm/hugetlb: refactor unmap_hugepage_range() to take folio instead of page mm/hugetlb: pass folio instead of page to unmap_ref_private() memcg: objcg stock trylock without irq disabling memcg: no stock lock for cpu hot-unplug memcg: make __mod_memcg_lruvec_state re-entrant safe against irqs memcg: make count_memcg_events re-entrant safe against irqs memcg: make mod_memcg_state re-entrant safe against irqs memcg: move preempt disable to callers of memcg_rstat_updated memcg: memcg_rstat_updated re-entrant safe against irqs mm: khugepaged: decouple SHMEM and file folios' collapse selftests/eventfd: correct test name and improve messages alloc_tag: check mem_profiling_support in alloc_tag_init Docs/damon: update titles and brief introductions to explain DAMOS selftests/damon/_damon_sysfs: read tried regions directories in order mm/damon/tests/core-kunit: add a test for damos_set_filters_default_reject() mm/damon/paddr: remove unused variable, folio_list, in damon_pa_stat() mm/damon/sysfs-schemes: fix wrong comment on damons_sysfs_quota_goal_metric_strs ... |
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Linus Torvalds
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dc76285144 |
vfs-6.16-rc1.writepage
-----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCaDBPTgAKCRCRxhvAZXjc ovkTAP9tyN24Oo+koY/2UedYBxM54cW4BCCRsVmkzfr8NSVdwwD/dg+v6gS8+nyD 3jlR0Z/08UyMHapB7fnAuFxPXXc8oAo= =e55o -----END PGP SIGNATURE----- Merge tag 'vfs-6.16-rc1.writepage' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull final writepage conversion from Christian Brauner: "This converts vboxfs from ->writepage() to ->writepages(). This was the last user of the ->writepage() method. So remove ->writepage() completely and all references to it" * tag 'vfs-6.16-rc1.writepage' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: fs: Remove aops->writepage mm: Remove swap_writepage() and shmem_writepage() ttm: Call shmem_writeout() from ttm_backup_backup_page() i915: Use writeback_iter() shmem: Add shmem_writeout() writeback: Remove writeback_use_writepage() migrate: Remove call to ->writepage vboxsf: Convert to writepages 9p: Add a migrate_folio method |
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Kairui Song
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dd309bfc68 |
mm, swap: remove no longer used swap mapping helper
This helper existed to fix the circular header dependency issue but it is
no longer used since commit
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Kairui Song
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7d0f0f0615 |
mm: move folio_index to mm/swap.h and remove no longer needed helper
There are no remaining users of folio_index() outside the mm subsystem. Move it to mm/swap.h to co-locate it with swap_cache_index(), eliminating a forward declaration, and a function call overhead. Also remove the helper that was used to fix circular header dependency issue. Link: https://lkml.kernel.org/r/20250430181052.55698-6-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Chao Yu <chao@kernel.org> Cc: Chris Li <chrisl@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Joanne Koong <joannelkoong@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Qu Wenruo <wqu@suse.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Linus Torvalds
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e238e49b18 |
vfs-6.15-rc7.fixes
-----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCaCHSPAAKCRCRxhvAZXjc ouxZAQCZcvUr0H7LO9j2JQdM+S7ABLU4T8El/f72tvFfapPJVgEA3zrAQ9qgZacv ytsmniyOnIzGsamPcK8Zy6LP6KjOYQ8= =xEE0 -----END PGP SIGNATURE----- Merge tag 'vfs-6.15-rc7.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs fixes from Christian Brauner: - Ensure that simple_xattr_list() always includes security.* xattrs - Fix eventpoll busy loop optimization when combined with timeouts - Disable swapon() for devices with block sizes greater than page sizes - Don't call errseq_set() twice during mark_buffer_write_io_error(). Just use mapping_set_error() which takes care to not deference unconditionally * tag 'vfs-6.15-rc7.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: fs: Remove redundant errseq_set call in mark_buffer_write_io_error. swapfile: disable swapon for bs > ps devices fs/eventpoll: fix endless busy loop after timeout has expired fs/xattr.c: fix simple_xattr_list to always include security.* xattrs |
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Kemeng Shi
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ec9827cd28 |
mm: swap: replace cluster_swap_free_nr() with swap_entries_put_[map/cache]()
Replace cluster_swap_free_nr() with swap_entries_put_[map/cache]() to remove repeat code and leverage batch-remove for entries with last flag. After removing cluster_swap_free_nr, only functions with "_nr" suffix could free entries spanning cross clusters. Add corresponding description in comment of swap_entries_put_map_nr() as is first function with "_nr" suffix and have a non-suffix variant function swap_entries_put_map(). Link: https://lkml.kernel.org/r/20250325162528.68385-9-shikemeng@huaweicloud.com Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Reviewed-by: Baoquan He <bhe@redhat.com> Cc: Kairui Song <kasong@tencent.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kemeng Shi
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d4f8000bd6 |
mm: swap: factor out helper to drop cache of entries within a single cluster
Factor out helper swap_entries_put_cache() from put_swap_folio() to serve as a general-purpose routine for dropping cache flag of entries within a single cluster. Link: https://lkml.kernel.org/r/20250325162528.68385-8-shikemeng@huaweicloud.com Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Reviewed-by: Baoquan He <bhe@redhat.com> Cc: Kairui Song <kasong@tencent.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kemeng Shi
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4d71d9062d |
mm: swap: free each cluster individually in swap_entries_put_map_nr()
1. Factor out general swap_entries_put_map() helper to drop entries belonging to one cluster. If entries are last map, free entries in batch, otherwise put entries with cluster lock acquired and released only once. 2. Iterate and call swap_entries_put_map() for each cluster in swap_entries_put_nr() to leverage batch-remove for last map belonging to one cluster and reduce lock acquire/release in fallback case. 3. As swap_entries_put_nr() won't handle SWAP_HSA_CACHE drop, rename it to swap_entries_put_map_nr(). 4. As we won't drop each entry invidually with swap_entry_put() now, do reclaim in free_swap_and_cache_nr() because swap_entries_put_map_nr() is general routine to drop reference and the relcaim work should only be done in free_swap_and_cache_nr(). Remove stale comment accordingly. Link: https://lkml.kernel.org/r/20250325162528.68385-7-shikemeng@huaweicloud.com Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Reviewed-by: Baoquan He <bhe@redhat.com> Cc: Kairui Song <kasong@tencent.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kemeng Shi
|
f2252acf44 |
mm: swap: drop last SWAP_MAP_SHMEM flag in batch in swap_entries_put_nr()
The SWAP_MAP_SHMEM indicates last map from shmem. Therefore we can drop SWAP_MAP_SHMEM in batch in similar way to drop last ref count in batch. Link: https://lkml.kernel.org/r/20250325162528.68385-6-shikemeng@huaweicloud.com Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Reviewed-by: Baoquan He <bhe@redhat.com> Cc: Kairui Song <kasong@tencent.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kemeng Shi
|
46e0ab2c62 |
mm: swap: use swap_entries_free() drop last ref count in swap_entries_put_nr()
Use swap_entries_free() to directly free swap entries when the swap entries are not cached and referenced, without needing to set swap entries to set intermediate SWAP_HAS_CACHE state. Link: https://lkml.kernel.org/r/20250325162528.68385-5-shikemeng@huaweicloud.com Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Reviewed-by: Baoquan He <bhe@redhat.com> Cc: Kairui Song <kasong@tencent.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kemeng Shi
|
835b868878 |
mm: swap: use swap_entries_free() to free swap entry in swap_entry_put_locked()
In swap_entry_put_locked(), we will set slot to SWAP_HAS_CACHE before using swap_entries_free() to do actual swap entry freeing. This introduce an unnecessary intermediate state. By using swap_entries_free() in swap_entry_put_locked(), we can eliminate the need to set slot to SWAP_HAS_CACHE. This change would make the behavior of swap_entry_put_locked() more consistent with other put() operations which will do actual free work after put last reference. Link: https://lkml.kernel.org/r/20250325162528.68385-4-shikemeng@huaweicloud.com Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Reviewed-by: Kairui Song <kasong@tencent.com> Reviewed-by: Baoquan He <bhe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kemeng Shi
|
64944ef6a1 |
mm: swap: enable swap_entry_range_free() to drop any kind of last ref
The original VM_BUG_ON only allows swap_entry_range_free() to drop last SWAP_HAS_CACHE ref. By allowing other kind of last ref in VM_BUG_ON, swap_entry_range_free() could be a more general-purpose function able to handle all kind of last ref. Following thi change, also rename swap_entry_range_free() to swap_entries_free() and update it's comment accordingly. This is a preparation to use swap_entries_free() to drop more kind of last ref other than SWAP_HAS_CACHE. [shikemeng@huaweicloud.com: add __maybe_unused attribute for swap_is_last_ref() and update comment] Link: https://lkml.kernel.org/r/20250410153908.612984-1-shikemeng@huaweicloud.com Link: https://lkml.kernel.org/r/20250325162528.68385-3-shikemeng@huaweicloud.com Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Reviewed-by: Baoquan He <bhe@redhat.com> Tested-by: SeongJae Park <sj@kernel.org> Cc: Kairui Song <kasong@tencent.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kemeng Shi
|
9c1c38bcdc |
mm: swap: rename __swap_[entry/entries]_free[_locked] to swap_[entry/entries]_put[_locked]
Patch series "Minor cleanups and improvements to swap freeing code", v4.
This series contains some cleanups and improvements which are made
during learning swapfile. Here is a summary of the changes:
1. Function naming improvments.
- Use "put" instead of "free" to name functions which only do actual
free when count drops to zero.
- Use "entry" to name function only frees one swap slot. Use
"entries" to name function could may free multi swap slots within one
cluster. Use "_nr" suffix to name function which could free multi
swap slots spanning cross multi clusters.
2. Eliminate the need to set swap slot to intermediate SWAP_HAS_CACHE
value before do actual free by using swap_entry_range_free()
3. Add helpers swap_entries_put_map() and swap_entries_put_cache() as
a general-purpose routine to free swap entries within a single cluster
which will try batch-remove first and fallback to put eatch entry
indvidually with cluster lock acquired/released only once. By using
these helpers, we could remove repeated code, levarage batch-remove in
more cases and aoivd to acquire/release cluster lock for each single
swap entry.
This patch (of 8):
In __swap_entry_free[_locked] and __swap_entries_free, we decrease count
first and only free swap entry if count drops to zero. This behavior is
more akin to a put() operation rather than a free() operation. Therefore,
rename these functions with "put" instead of "free". Additionally, add
"_nr" suffix to swap_entries_put to indicate the input range may span swap
clusters.
Link: https://lkml.kernel.org/r/20250325162528.68385-1-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20250325162528.68385-2-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Kairui Song <kasong@tencent.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Kairui Song
|
9a9794a81a |
mm, swap: fix false warning for large allocation with !THP_SWAP
The !CONFIG_THP_SWAP check existed before just fine because slot cache
would reject high order allocation and let the caller split all folios and
try again.
But slot cache is gone, so large allocation will directly go to the
allocator, and the allocator should just fail silently to inform caller to
do the folio split, this is totally fine and expected.
Remove this meaningless warning.
Link: https://lkml.kernel.org/r/20250429094803.85518-1-ryncsn@gmail.com
Fixes:
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|
Luis Chamberlain
|
6ba0982c32
|
swapfile: disable swapon for bs > ps devices
Devices which have a requirement for bs > ps cannot be supported for swap as swap still needs work. Now that the block device cache sets the min order for block devices we need this stop gap otherwise all swap operations are rejected. Without this you'll end up with errors on these devices as the swap code still needs much love to support min order. With this we at least now put a stop gap of its use, until the swap subsystem completes its major overhaul: mkswap: /dev/nvme3n1: warning: wiping old swap signature. Setting up swapspace version 1, size = 100 GiB (107374178304 bytes) no label, UUID=6af76b5c-7e7b-4902-b7f7-4c24dde6fa36 swapon: /dev/nvme3n1: swapon failed: Invalid argument Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Link: https://lore.kernel.org/aBkS926thy9zvdZb@bombadil.infradead.org Signed-off-by: Christian Brauner <brauner@kernel.org> |
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Matthew Wilcox (Oracle)
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84798514db
|
mm: Remove swap_writepage() and shmem_writepage()
Call swap_writeout() and shmem_writeout() from pageout() instead. Signed-off-by: "Matthew Wilcox (Oracle)" <willy@infradead.org> Link: https://lore.kernel.org/r/20250402150005.2309458-9-willy@infradead.org Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Christian Brauner <brauner@kernel.org> |
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Kairui Song
|
b487a2da35 |
mm, swap: simplify folio swap allocation
With slot cache gone, clean up the allocation helpers even more. folio_alloc_swap will be the only entry for allocation and adding the folio to swap cache (except suspend), making it opposite of folio_free_swap. Link: https://lkml.kernel.org/r/20250313165935.63303-8-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Chris Li <chrisl@kernel.org> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Matthew Wilcow (Oracle) <willy@infradead.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kairui Song
|
0ff67f990b |
mm, swap: remove swap slot cache
Slot cache is no longer needed now, removing it and all related code.
- vm-scalability with: `usemem --init-time -O -y -x -R -31 1G`,
12G memory cgroup using simulated pmem as SWAP (32G pmem, 32 CPUs),
16 test runs for each case, measuring the total throughput:
Before (KB/s) (stdev) After (KB/s) (stdev)
Random (4K): 424907.60 (24410.78) 414745.92 (34554.78)
Random (64K): 163308.82 (11635.72) 167314.50 (18434.99)
Sequential (4K, !-R): 6150056.79 (103205.90) 6321469.06 (115878.16)
The performance changes are below noise level.
- Build linux kernel with make -j96, using 4K folio with 1.5G memory
cgroup limit and 64K folio with 2G memory cgroup limit, on top of tmpfs,
12 test runs, measuring the system time:
Before (s) (stdev) After (s) (stdev)
make -j96 (4K): 6445.69 (61.95) 6408.80 (69.46)
make -j96 (64K): 6841.71 (409.04) 6437.99 (435.55)
Similar to above, 64k mTHP case showed a slight improvement.
Link: https://lkml.kernel.org/r/20250313165935.63303-7-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Kairui Song
|
1b7e90020e |
mm, swap: use percpu cluster as allocation fast path
Current allocation workflow first traverses the plist with a global lock held, after choosing a device, it uses the percpu cluster on that swap device. This commit moves the percpu cluster variable out of being tied to individual swap devices, making it a global percpu variable, and will be used directly for allocation as a fast path. The global percpu cluster variable will never point to a HDD device, and allocations on a HDD device are still globally serialized. This improves the allocator performance and prepares for removal of the slot cache in later commits. There shouldn't be much observable behavior change, except one thing: this changes how swap device allocation rotation works. Currently, each allocation will rotate the plist, and because of the existence of slot cache (one order 0 allocation usually returns 64 entries), swap devices of the same priority are rotated for every 64 order 0 entries consumed. High order allocations are different, they will bypass the slot cache, and so swap device is rotated for every 16K, 32K, or up to 2M allocation. The rotation rule was never clearly defined or documented, it was changed several times without mentioning. After this commit, and once slot cache is gone in later commits, swap device rotation will happen for every consumed cluster. Ideally non-HDD devices will be rotated if 2M space has been consumed for each order. Fragmented clusters will rotate the device faster, which seems OK. HDD devices is rotated for every allocation regardless of the allocation order, which should be OK too and trivial. This commit also slightly changes allocation behaviour for slot cache. The new added cluster allocation fast path may allocate entries from different device to the slot cache, this is not observable from user space, only impact performance very slightly, and slot cache will be just gone in next commit, so this can be ignored. Link: https://lkml.kernel.org/r/20250313165935.63303-6-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Chris Li <chrisl@kernel.org> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Matthew Wilcow (Oracle) <willy@infradead.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kairui Song
|
280cfccaa2 |
mm, swap: don't update the counter up-front
The counter update before allocation design was useful to avoid unnecessary scan when device is full, so it will abort early if the counter indicates the device is full. But that is an uncommon case, and now scanning of a full device is very fast, so the up-front update is not helpful any more. Remove it and simplify the slot allocation logic. Link: https://lkml.kernel.org/r/20250313165935.63303-5-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Reviewed-by: Baoquan He <bhe@redhat.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Chris Li <chrisl@kernel.org> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Matthew Wilcow (Oracle) <willy@infradead.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kairui Song
|
3123fb0a18 |
mm, swap: drop the flag TTRS_DIRECT
This flag exists temporarily to allow the allocator to bypass the slot cache during freeing, so reclaiming one slot will free the slot immediately. But now we have already removed slot cache usage on freeing, so this flag has no effect now. Link: https://lkml.kernel.org/r/20250313165935.63303-3-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Reviewed-by: Baoquan He <bhe@redhat.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Chris Li <chrisl@kernel.org> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Matthew Wilcow (Oracle) <willy@infradead.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kairui Song
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fae8595505 |
mm, swap: avoid reclaiming irrelevant swap cache
Patch series "mm, swap: remove swap slot cache", v3.
Slot cache was initially introduced by commit
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Kemeng Shi
|
0a8a5b6c41 |
mm: swap: remove stale comment of swap_reclaim_full_clusters()
swap_reclaim_full_clusters() has no return value now, just remove the stale comment which says swap_reclaim_full_clusters() wil return a bool value. Link: https://lkml.kernel.org/r/20250222160850.505274-7-shikemeng@huaweicloud.com Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Cc: Kairui Song <ryncsn@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kemeng Shi
|
2310f08942 |
mm, swap: correct comment in swap_usage_sub()
We will add si back to plist in swap_usage_sub(), just correct the wrong comment which says we will remove si from plist in swap_usage_sub(). Link: https://lkml.kernel.org/r/20250222160850.505274-6-shikemeng@huaweicloud.com Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Cc: Kairui Song <ryncsn@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kemeng Shi
|
43e9bbc3bb |
mm, swap: remove setting SWAP_MAP_BAD for discard cluster
Before alloc from a cluster, we will aqcuire cluster's lock and make sure it is usable by cluster_is_usable(), so there is no need to set SWAP_MAP_BAD for cluster to be discarded. Link: https://lkml.kernel.org/r/20250222160850.505274-5-shikemeng@huaweicloud.com Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Kairui Song <kasong@tencent.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Baoquan He
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1d212293ff |
mm/swapfile.c: open code cluster_alloc_swap()
It's only called in scan_swap_map_slots(). And also remove the stale code comment in scan_swap_map_slots() because it's not fit for the current cluster allocation mechanism. Link: https://lkml.kernel.org/r/20250205092721.9395-13-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Chris Li <chrisl@kernel.org> Cc: Kairui Song <ryncsn@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Baoquan He
|
4ccd4154fa |
mm/swapfile.c: remove the incorrect code comment
Since commit
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|
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Baoquan He
|
c523aa8907 |
mm/swap: rename swap_swapcount() to swap_entry_swapped()
The new function name can reflect the real behaviour of the function more clearly and more accurately. And the renaming avoids the confusion between swap_swapcount() and swp_swapcount(). Link: https://lkml.kernel.org/r/20250205092721.9395-11-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Chris Li <chrisl@kernel.org> Cc: Kairui Song <ryncsn@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Baoquan He
|
ac2d326828 |
mm/swapfile.c: remove the unneeded checking
In free_swap_and_cache_nr(), invocation of get_swap_device() has done the checking if it's a swap entry. So remove the redundant checking here. Link: https://lkml.kernel.org/r/20250205092721.9395-10-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Chris Li <chrisl@kernel.org> Cc: Kairui Song <ryncsn@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Baoquan He
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a46a6bc21c |
mm/swapfile.c: optimize code in setup_clusters()
In the last 'for' loop inside setup_clusters(), using two local variable 'k' and 'j' are obvisouly redundant. Using 'j' is enough and simpler. And also move macro SWAP_CLUSTER_COLS close to its only user setup_clusters(). Link: https://lkml.kernel.org/r/20250205092721.9395-8-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Chris Li <chrisl@kernel.org> Cc: Kairui Song <ryncsn@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Baoquan He
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f80ddc148c |
mm/swapfile.c: update the code comment above swap_count_continued()
Now, swap_count_continued() has two callers, __swap_duplicate() and __swap_entry_free_locked(), the relevant code comment is stale. Update it to reflect the current situation. [bhe@redhat.com: v2] Link: https://lkml.kernel.org/r/Z6V0/UvG1fvkQ4t/@fedora Link: https://lkml.kernel.org/r/20250205092721.9395-7-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Chris Li <chrisl@kernel.org> Cc: Kairui Song <ryncsn@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Baoquan He
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b4735d94c2 |
mm/swap: rename swap_is_has_cache() to swap_only_has_cache()
There are two predicates in the name of swap_is_has_cache() which is confusing. Renaming it to remove the confusion and can better reflect its functionality. Link: https://lkml.kernel.org/r/20250205092721.9395-6-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Chris Li <chrisl@kernel.org> Cc: Kairui Song <ryncsn@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Baoquan He
|
9b9cba7289 |
mm/swap: skip scanning cluster range if it's empty cluster
Since ci->lock has been taken when isolating cluster from si->free_clusters or taking si->percpu_cluster->next[order], it's unnecessary to scan and check the cluster range availability if i'ts empty cluster, and this can accelerate the huge page swapping. Link: https://lkml.kernel.org/r/20250205092721.9395-5-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Chris Li <chrisl@kernel.org> Cc: Kairui Song <ryncsn@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Baoquan He
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0eb7d2c337 |
mm/swap: remove SWAP_FLAG_PRIO_SHIFT
It doesn't make sense to have a zero value of shift. Remove it to avoid confusion. Link: https://lkml.kernel.org/r/20250205092721.9395-4-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Chris Li <chrisl@kernel.org> Cc: Kairui Song <ryncsn@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kemeng Shi
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57d910cffa |
mm, swap: avoid BUG_ON in relocate_cluster()
If allocation is racy with swapoff, we may call free_cluster for cluster
already in free list and trigger BUG_ON() as following:
Allocation Swapoff
cluster_alloc_swap_entry
...
/* may get a free cluster with offset */
offset = xxx;
if (offset)
ci = lock_cluster(si, offset);
...
del_from_avail_list(p, true);
si->flags &= ~SWP_WRITEOK;
alloc_swap_scan_cluster(si, ci, ...)
...
/* failed to alloc entry from free entry */
if (!cluster_alloc_range(...))
break;
...
/* add back a free cluster */
relocate_cluster(si, ci);
if (!ci->count)
free_cluster(si, ci);
VM_BUG_ON(ci->flags == CLUSTER_FLAG_FREE);
To prevent the BUG_ON(), call free_cluster() for free cluster to move the
cluster to tail of list.
Check cluster is not free before calling free_cluster() in
relocate_cluster() to avoid BUG_ON().
Link: https://lkml.kernel.org/r/20250222160850.505274-4-shikemeng@huaweicloud.com
Fixes:
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Kemeng Shi
|
7a2e7ae5d1 |
mm: swap: use correct step in loop to wait all clusters in wait_for_allocation()
Use correct step in loop to wait all clusters in wait_for_allocation().
If we miss some cluster in wait_for_allocation(), use after free may occur
as follows:
shmem_writepage swapoff
folio_alloc_swap
get_swap_pages
scan_swap_map_slots
cluster_alloc_swap_entry
alloc_swap_scan_cluster
cluster_alloc_range
/* SWP_WRITEOK is valid */
if (!(si->flags & SWP_WRITEOK))
...
del_from_avail_list(p, true);
...
/* miss the cluster in shmem_writepage */
wait_for_allocation()
...
try_to_unuse()
memset(si->swap_map + start, usage, nr_pages);
swap_range_alloc(si, nr_pages);
ci->count += nr_pages;
/* return a valid entry */
...
exit_swap_address_space(p->type);
...
...
add_to_swap_cache
/* dereference swap_address_space(entry) which is NULL */
xas_lock_irq(&xas);
Link: https://lkml.kernel.org/r/20250222160850.505274-3-shikemeng@huaweicloud.com
Fixes:
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|
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Kemeng Shi
|
51f271c194 |
mm: swap: add back full cluster when no entry is reclaimed
If no swap cache is reclaimed, cluster taken off from full_clusters list
will not be put in any list and we can't reclaime HAS_CACHE slots
efficiently. Do relocate_cluster for such cluster to avoid inefficiency.
Link: https://lkml.kernel.org/r/20250224113910.522439-1-shikemeng@huaweicloud.com
Fixes:
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gao xu
|
c3e998398d |
mm: fix possible NULL pointer dereference in __swap_duplicate
Add a NULL check on the return value of swp_swap_info in __swap_duplicate to prevent crashes caused by NULL pointer dereference. The reason why swp_swap_info() returns NULL is unclear; it may be due to CPU cache issues or DDR bit flips. The probability of this issue is very small - it has been observed to occur approximately 1 in 500,000 times per week. The stack info we encountered is as follows: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000058 [RB/E]rb_sreason_str_set: sreason_str set null_pointer Mem abort info: ESR = 0x0000000096000005 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x05: level 1 translation fault Data abort info: ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 user pgtable: 4k pages, 39-bit VAs, pgdp=00000008a80e5000 [0000000000000058] pgd=0000000000000000, p4d=0000000000000000, pud=0000000000000000 Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP Skip md ftrace buffer dump for: 0x1609e0 ... pc : swap_duplicate+0x44/0x164 lr : copy_page_range+0x508/0x1e78 sp : ffffffc0f2a699e0 x29: ffffffc0f2a699e0 x28: ffffff8a5b28d388 x27: ffffff8b06603388 x26: ffffffdf7291fe70 x25: 0000000000000006 x24: 0000000000100073 x23: 00000000002d2d2f x22: 0000000000000008 x21: 0000000000000000 x20: 00000000002d2d2f x19: 18000000002d2d2f x18: ffffffdf726faec0 x17: 0000000000000000 x16: 0010000000000001 x15: 0040000000000001 x14: 0400000000000001 x13: ff7ffffffffffb7f x12: ffeffffffffffbff x11: ffffff8a5c7e1898 x10: 0000000000000018 x9 : 0000000000000006 x8 : 1800000000000000 x7 : 0000000000000000 x6 : ffffff8057c01f10 x5 : 000000000000a318 x4 : 0000000000000000 x3 : 0000000000000000 x2 : 0000006daf200000 x1 : 0000000000000001 x0 : 18000000002d2d2f Call trace: swap_duplicate+0x44/0x164 copy_page_range+0x508/0x1e78 copy_process+0x1278/0x21cc kernel_clone+0x90/0x438 __arm64_sys_clone+0x5c/0x8c invoke_syscall+0x58/0x110 do_el0_svc+0x8c/0xe0 el0_svc+0x38/0x9c el0t_64_sync_handler+0x44/0xec el0t_64_sync+0x1a8/0x1ac Code: 9139c35a 71006f3f 54000568 f8797b55 (f9402ea8) ---[ end trace 0000000000000000 ]--- Kernel panic - not syncing: Oops: Fatal exception SMP: stopping secondary CPUs The patch seems to only provide a workaround, but there are no more effective software solutions to handle the bit flips problem. This path will change the issue from a system crash to a process exception, thereby reducing the impact on the entire machine. akpm: this is probably a kernel bug, but this patch keeps the system running and doesn't reduce that bug's debuggability. Link: https://lkml.kernel.org/r/e223b0e6ba2f4924984b1917cc717bd5@honor.com Signed-off-by: gao xu <gaoxu2@honor.com> Reviewed-by: Barry Song <baohua@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Yosry Ahmed <yosry.ahmed@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kairui Song
|
498c48c66e |
mm, swap: fix reclaim offset calculation error during allocation
There is a code error that will cause the swap entry allocator to reclaim
and check the whole cluster with an unexpected tail offset instead of the
part that needs to be reclaimed. This may cause corruption of the swap
map, so fix it.
Link: https://lkml.kernel.org/r/20250130115131.37777-1-ryncsn@gmail.com
Fixes:
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|
|
Kairui Song
|
4f79384a25 |
mm, swap_slots: remove slot cache for freeing path
The slot cache for freeing path is mostly for reducing the overhead of si->lock. As we have basically eliminated the si->lock usage for freeing path, it can be removed. This helps simplify the code, and avoids swap entries from being hold in cache upon freeing. The delayed freeing of entries have been causing trouble for further optimizations for zswap [1] and in theory will also cause more fragmentation, and extra overhead. Test with build linux kernel showed both performance and fragmentation is better without the cache: tiem make -j96 / 768M memcg, 4K pages, 10G ZRAM, avg of 4 test run:: Before: Sys time: 36047.78, Real time: 472.43 After: (-7.6% sys time, -7.3% real time) Sys time: 33314.76, Real time: 437.67 time make -j96 / 1152M memcg, 64K mTHP, 10G ZRAM, avg of 4 test run: Before: Sys time: 46859.04, Real time: 562.63 hugepages-64kB/stats/swpout: 1783392 hugepages-64kB/stats/swpout_fallback: 240875 After: (-23.3% sys time, -21.3% real time) Sys time: 35958.87, Real time: 442.69 hugepages-64kB/stats/swpout: 1866267 hugepages-64kB/stats/swpout_fallback: 158330 Sequential SWAP should be also slightly faster, tests didn't show a measurable difference though, at least no regression: Swapin 4G zero page on ZRAM (time in us): Before (avg. 1923756) |
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Kairui Song
|
bae8a4ef3e |
mm, swap: use a global swap cluster for non-rotation devices
Non-rotational devices (SSD / ZRAM) can tolerate fragmentation, so the goal of the SWAP allocator is to avoid contention for clusters. It uses a per-CPU cluster design, and each CPU will use a different cluster as much as possible. However, HDDs are very sensitive to fragmentation, contention is trivial in comparison. Therefore, we use one global cluster instead. This ensures that each order will be written to the same cluster as much as possible, which helps make the I/O more continuous. This ensures that the performance of the cluster allocator is as good as that of the old allocator. Tests after this commit compared to those before this series: Tested using 'make -j32' with tinyconfig, a 1G memcg limit, and HDD swap: make -j32 with tinyconfig, using 1G memcg limit and HDD swap: Before this series: 114.44user 29.11system 39:42.90elapsed 6%CPU (0avgtext+0avgdata 157284maxresident)k 2901232inputs+0outputs (238877major+4227640minor)pagefaults After this commit: 113.90user 23.81system 38:11.77elapsed 6%CPU (0avgtext+0avgdata 157260maxresident)k 2548728inputs+0outputs (235471major+4238110minor)pagefaults [ryncsn@gmail.com: check kmalloc() return in setup_clusters] Link: https://lkml.kernel.org/r/CAMgjq7Au+o04ckHyT=iU-wVx9az=t0B-ZiC5E0bDqNrAtNOP-g@mail.gmail.com Link: https://lkml.kernel.org/r/20250113175732.48099-13-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Suggested-by: Chris Li <chrisl@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickens <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kairui Song
|
3f641cf938 |
mm, swap: introduce a helper for retrieving cluster from offset
It's a common operation to retrieve the cluster info from offset, introduce a helper for this. Link: https://lkml.kernel.org/r/20250113175732.48099-12-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Suggested-by: Chris Li <chrisl@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickens <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
|
|
Kairui Song
|
e3ae2dec84 |
mm, swap: simplify percpu cluster updating
Instead of using a returning argument, we can simply store the next cluster offset to the fixed percpu location, which reduce the stack usage and simplify the function: Object size: ./scripts/bloat-o-meter mm/swapfile.o mm/swapfile.o.new add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-271 (-271) Function old new delta get_swap_pages 2847 2733 -114 alloc_swap_scan_cluster 894 737 -157 Total: Before=30833, After=30562, chg -0.88% Stack usage: Before: swapfile.c:1190:5:get_swap_pages 240 static After: swapfile.c:1185:5:get_swap_pages 216 static Link: https://lkml.kernel.org/r/20250113175732.48099-11-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Chis Li <chrisl@kernel.org> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickens <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
|
|
Kairui Song
|
3b644773ee |
mm, swap: reduce contention on device lock
Currently, swap locking is mainly composed of two locks: the cluster lock
(ci->lock) and the device lock (si->lock).
The cluster lock is much more fine-grained, so it is best to use ci->lock
instead of si->lock as much as possible.
We have cleaned up other hard dependencies on si->lock. Following the new
cluster allocator design, most operations don't need to touch si->lock at
all. In practice, we only need to take si->lock when moving clusters
between lists.
To achieve this, this commit reworks the locking pattern of all si->lock
and ci->lock users, eliminates all usage of ci->lock inside si->lock, and
introduces a new design to avoid touching si->lock unless needed.
For minimal contention and easier understanding of the system, two ideas
are introduced with the corresponding helpers: isolation and relocation.
- Clusters will be `isolated` from the list when iterating the list
to search for an allocatable cluster.
This ensures other CPUs won't walk into the same cluster easily,
and it releases si->lock after acquiring ci->lock, providing the
only place that handles the inversion of two locks, and avoids
contention.
Iterating the cluster list almost always moves the cluster
(free -> nonfull, nonfull -> frag, frag -> frag tail), but it
doesn't know where the cluster should be moved to until scanning
is done. So keeping the cluster off-list is a good option with
low overhead.
The off-list time window of a cluster is also minimal. In the worst
case, one CPU will return the cluster after scanning the 512 entries
on it, which we used to busy wait with a spin lock.
This is done with the new helper `isolate_lock_cluster`.
- Clusters will be `relocated` after allocation or freeing, according
to their usage count and status.
Allocations no longer hold si->lock now, and may drop ci->lock for
reclaim, so the cluster could be moved to any location while no lock
is held. Besides, isolation clears all flags when it takes the
cluster off the list (the flags must be in sync with the list status,
so cluster users don't need to touch si->lock for checking its list
status). So the cluster has to be relocated to the right list
according to its usage after allocation or freeing.
Relocation is optional, if the cluster flags indicate it's already
on the right list, it will skip touching the list or si->lock.
This is done with `relocate_cluster` after allocation or with
`[partial_]free_cluster` after freeing.
This handled usage of all kinds of clusters in a clean way.
Scanning and allocation by iterating the cluster list is handled by
"isolate - <scan / allocate> - relocate".
Scanning and allocation of per-CPU clusters will only involve
"<scan / allocate> - relocate", as it knows which cluster to lock
and use.
Freeing will only involve "relocate".
Each CPU will keep using its per-CPU cluster until the 512 entries
are all consumed. Freeing also has to free 512 entries to trigger
cluster movement in the best case, so si->lock is rarely touched.
Testing with building the Linux kernel with defconfig showed huge
improvement:
tiem make -j96 / 768M memcg, 4K pages, 10G ZRAM, on Intel 8255C:
Before:
Sys time: 73578.30, Real time: 864.05
After: (-50.7% sys time, -44.8% real time)
Sys time: 36227.49, Real time: 476.66
time make -j96 / 1152M memcg, 64K mTHP, 10G ZRAM, on Intel 8255C:
(avg of 4 test run)
Before:
Sys time: 74044.85, Real time: 846.51
hugepages-64kB/stats/swpout:
|
|
|
Kairui Song
|
3494d18470 |
mm, swap: use an enum to define all cluster flags and wrap flags changes
Currently, we are only using flags to indicate which list the cluster is on. Using one bit for each list type might be a waste, as the list type grows, we will consume too many bits. Additionally, the current mixed usage of '&' and '==' is a bit confusing. Make it clean by using an enum to define all possible cluster statuses. Only an off-list cluster will have the NONE (0) flag. And use a wrapper to annotate and sanitize all flag settings and list movements. Link: https://lkml.kernel.org/r/20250113175732.48099-9-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Suggested-by: Chris Li <chrisl@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickens <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
|
|
Kairui Song
|
9a0ddeb798 |
mm, swap: hold a reference during scan and cleanup flag usage
The flag SWP_SCANNING was used as an indicator of whether a device is being scanned for allocation, and prevents swapoff. Combined with SWP_WRITEOK, they work as a set of barriers for a clean swapoff: 1. Swapoff clears SWP_WRITEOK, allocation requests will see ~SWP_WRITEOK and abort as it's serialized by si->lock. 2. Swapoff unuses all allocated entries. 3. Swapoff waits for SWP_SCANNING flag to be cleared, so ongoing allocations will stop, preventing UAF. 4. Now swapoff can free everything safely. This will make the allocation path have a hard dependency on si->lock. Allocation always have to acquire si->lock first for setting SWP_SCANNING and checking SWP_WRITEOK. This commit removes this flag, and just uses the existing per-CPU refcount instead to prevent UAF in step 3, which serves well for such usage without dependency on si->lock, and scales very well too. Just hold a reference during the whole scan and allocation process. Swapoff will kill and wait for the counter. And for preventing any allocation from happening after step 1 so the unuse in step 2 can ensure all slots are free, swapoff will acquire the ci->lock of each cluster one by one to ensure all allocations see ~SWP_WRITEOK and abort. This way these dependences on si->lock are gone. And worth noting we can't kill the refcount as the first step for swapoff as the unuse process have to acquire the refcount. Link: https://lkml.kernel.org/r/20250113175732.48099-8-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Chis Li <chrisl@kernel.org> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickens <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |