kernel/linux.git/mm/page_io.c, branch v7.0

mm: fix minor spelling mistakes in comments

2026-01-21T03:24:48+00:00

Correct several typos in comments across files in mm/ [akpm@linux-foundation.org: also fix comment grammar, per SeongJae] Link: https://lkml.kernel.org/r/20251218150906.25042-1-klourencodev@gmail.com Signed-off-by: Kevin Lourenco Reviewed-by: SeongJae Park Acked-by: David Hildenbrand (Red Hat) Reviewed-by: Lorenzo Stoakes Signed-off-by: Andrew Morton

mm, swap: tidy up swap device and cluster info helpers

2025-09-21T21:22:23+00:00

swp_swap_info is the most commonly used helper for retrieving swap info. It has an internal check that may lead to a NULL return value, but almost none of its caller checks the return value, making the internal check pointless. In fact, most of these callers already ensured the entry is valid and never expect a NULL value. Tidy this up and improve the function names. If the caller can make sure the swap entry/type is valid and the device is pinned, use the new introduced __swap_entry_to_info/__swap_type_to_info instead. They have more debug sanity checks and lower overhead as they are inlined. Callers that may expect a NULL value should use swap_entry_to_info/swap_type_to_info instead. No feature change. The rearranged codes should have had no effect, or they should have been hitting NULL de-ref bugs already. Only some new sanity checks are added so potential issues may show up in debug build. The new helpers will be frequently used with swap table later when working with swap cache folios. A locked swap cache folio ensures the entries are valid and stable so these helpers are very helpful. Link: https://lkml.kernel.org/r/20250916160100.31545-8-ryncsn@gmail.com Signed-off-by: Kairui Song Acked-by: Chris Li Reviewed-by: Barry Song Acked-by: David Hildenbrand Suggested-by: Chris Li Cc: Baolin Wang Cc: Baoquan He Cc: "Huang, Ying" Cc: Hugh Dickins Cc: Johannes Weiner Cc: Kemeng Shi Cc: kernel test robot Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Nhat Pham Cc: Yosry Ahmed Cc: Zi Yan Cc: SeongJae Park Signed-off-by: Andrew Morton

mm: stop passing a writeback_control structure to swap_writeout

2025-07-10T05:41:58+00:00

swap_writeout only needs the swap_iocb cookie from the writeback_control structure, so pass it explicitly. Link: https://lkml.kernel.org/r/20250610054959.2057526-6-hch@lst.de Signed-off-by: Christoph Hellwig Cc: Baolin Wang Cc: Chengming Zhou Cc: Hugh Dickins Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Nhat Pham Signed-off-by: Andrew Morton

mm: stop passing a writeback_control structure to __swap_writepage

2025-07-10T05:41:57+00:00

__swap_writepage only needs the swap_iocb cookie from the writeback_control structure, so pass it explicitly and remove the now unused swap_iocb member from struct writeback_control. Link: https://lkml.kernel.org/r/20250610054959.2057526-5-hch@lst.de Signed-off-by: Christoph Hellwig Acked-by: Nhat Pham Cc: Baolin Wang Cc: Chengming Zhou Cc: Hugh Dickins Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton

mm: tidy up swap_writeout

2025-07-10T05:41:57+00:00

Use a goto label to consolidate the unlock folio and return pattern and don't bother with an else after a return / goto. Link: https://lkml.kernel.org/r/20250610054959.2057526-4-hch@lst.de Signed-off-by: Christoph Hellwig Cc: Baolin Wang Cc: Chengming Zhou Cc: Hugh Dickins Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Nhat Pham Signed-off-by: Andrew Morton

mm: Remove swap_writepage() and shmem_writepage()

2025-04-07T07:36:50+00:00

Call swap_writeout() and shmem_writeout() from pageout() instead. Signed-off-by: "Matthew Wilcox (Oracle)" Link: https://lore.kernel.org/r/20250402150005.2309458-9-willy@infradead.org Tested-by: Baolin Wang Reviewed-by: Baolin Wang Signed-off-by: Christian Brauner

page_io: zswap: do not crash the kernel on decompression failure

2025-03-18T05:06:50+00:00

Currently, we crash the kernel when a decompression failure occurs in zswap (either because of memory corruption, or a bug in the compression algorithm). This is overkill. We should only SIGBUS the unfortunate process asking for the zswap entry on zswap load, and skip the corrupted entry in zswap writeback. See [1] for a recent upstream discussion about this. The zswap writeback case is relatively straightforward to fix. For the zswap_load() case, we change the return behavior: * Return 0 on success. * Return -ENOENT (with the folio locked) if zswap does not own the swapped out content. * Return -EIO if zswap owns the swapped out content, but encounters a decompression failure for some reasons. The folio will be unlocked, but not be marked up-to-date, which will eventually cause the process requesting the page to SIGBUS (see the handling of not-up-to-date folio in do_swap_page() in mm/memory.c), without crashing the kernel. * Return -EINVAL if we encounter a large folio, as large folio should not be swapped in while zswap is being used. Similar to the -EIO case, we also unlock the folio but do not mark it as up-to-date to SIGBUS the faulting process. As a side effect, we require one extra zswap tree traversal in the load and writeback paths. Quick benchmarking on a kernel build test shows no performance difference: With the new scheme: real: mean: 125.1s, stdev: 0.12s user: mean: 3265.23s, stdev: 9.62s sys: mean: 2156.41s, stdev: 13.98s The old scheme: real: mean: 125.78s, stdev: 0.45s user: mean: 3287.18s, stdev: 5.95s sys: mean: 2177.08s, stdev: 26.52s [nphamcs@gmail.com: fix documentation of zswap_load()] Link: https://lkml.kernel.org/r/20250306222453.1269456-1-nphamcs@gmail.com Link: https://lore.kernel.org/all/ZsiLElTykamcYZ6J@casper.infradead.org/ [1] Link: https://lkml.kernel.org/r/20250306205011.784787-1-nphamcs@gmail.com Signed-off-by: Nhat Pham Suggested-by: Matthew Wilcox Suggested-by: Yosry Ahmed Suggested-by: Johannes Weiner Reviewed-by: Chengming Zhou Acked-by: Johannes Weiner Signed-off-by: Andrew Morton

mm, swap: clean up device availability check

2025-01-26T04:22:36+00:00

Remove highest_bit and lowest_bit. After the HDD allocation path has been removed, the only purpose of these two fields is to determine whether the device is full or not, which can instead be determined by checking the inuse_pages. Link: https://lkml.kernel.org/r/20250113175732.48099-6-ryncsn@gmail.com Signed-off-by: Kairui Song Reviewed-by: Baoquan He Cc: Barry Song Cc: Chis Li Cc: "Huang, Ying" Cc: Hugh Dickens Cc: Johannes Weiner Cc: Kalesh Singh Cc: Nhat Pham Cc: Ryan Roberts Cc: Yosry Ahmed Signed-off-by: Andrew Morton

mm: add per-order mTHP swpin counters

2024-11-11T08:26:43+00:00

This helps profile the sizes of folios being swapped in. Currently, only mTHP swap-out is being counted. The new interface can be found at: /sys/kernel/mm/transparent_hugepage/hugepages-/stats swpin For example, cat /sys/kernel/mm/transparent_hugepage/hugepages-64kB/stats/swpin 12809 cat /sys/kernel/mm/transparent_hugepage/hugepages-32kB/stats/swpin 4763 [v-songbaohua@oppo.com: add a blank line in doc] Link: https://lkml.kernel.org/r/20241030233423.80759-1-21cnbao@gmail.com Link: https://lkml.kernel.org/r/20241026082423.26298-1-21cnbao@gmail.com Signed-off-by: Barry Song Reviewed-by: Baolin Wang Acked-by: David Hildenbrand Cc: Chris Li Cc: Yosry Ahmed Cc: "Huang, Ying" Cc: Kairui Song Cc: Ryan Roberts Cc: Kanchana P Sridhar Cc: Usama Arif Signed-off-by: Andrew Morton

mm: swap: count successful large folio zswap stores in hugepage zswpout stats

2024-11-11T08:26:43+00:00

Added a new MTHP_STAT_ZSWPOUT entry to the sysfs transparent_hugepage stats so that successful large folio zswap stores can be accounted under the per-order sysfs "zswpout" stats: /sys/kernel/mm/transparent_hugepage/hugepages-*kB/stats/zswpout Other non-zswap swap device swap-out events will be counted under the existing sysfs "swpout" stats: /sys/kernel/mm/transparent_hugepage/hugepages-*kB/stats/swpout Also, added documentation for the newly added sysfs per-order hugepage "zswpout" stats. The documentation clarifies that only non-zswap swapouts will be accounted in the existing "swpout" stats. Link: https://lkml.kernel.org/r/20241001053222.6944-8-kanchana.p.sridhar@intel.com Signed-off-by: Kanchana P Sridhar Reviewed-by: Nhat Pham Cc: Chengming Zhou Cc: "Huang, Ying" Cc: Johannes Weiner Cc: Matthew Wilcox Cc: Ryan Roberts Cc: Shakeel Butt Cc: Usama Arif Cc: Wajdi Feghali Cc: Yosry Ahmed Cc: "Zou, Nanhai" Cc: Barry Song <21cnbao@gmail.com> Signed-off-by: Andrew Morton