- 06 May, 2024 40 commits
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Kemeng Shi authored
The __folio_mark_dirty will not mark inode dirty any longer. Remove the stale comment of it. Link: https://lkml.kernel.org/r/20240425131724.36778-5-shikemeng@huaweicloud.comSigned-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Howard Cochran <hcochran@kernelspring.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Miklos Szeredi <mszeredi@redhat.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Kemeng Shi authored
Call __wb_calc_thresh to calculate wb bg_thresh of gdtc in wb_over_bg_thresh to remove unnecessary wrap in wb_calc_thresh. Link: https://lkml.kernel.org/r/20240425131724.36778-4-shikemeng@huaweicloud.comSigned-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Howard Cochran <hcochran@kernelspring.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miklos Szeredi <mszeredi@redhat.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Kemeng Shi authored
wb_calc_thresh() is calculating wb's share of bg_thresh in the global domain. However in case of cgroup writeback this is not the right thing to do. Consider the following domain hierarchy: global domain (> 20G) / \ cgroup1 (10G) cgroup2 (10G) | | bdi wb1 wb2 and assume wb1 and wb2 have the same bandwidth and the background threshold is set at 10%. The bg_thresh of cgroup1 and cgroup2 is going to be 1G. Now because wb_calc_thresh(mdtc->wb, mdtc->bg_thresh) calculates per-wb threshold in the global domain as (wb bandwidth) / (domain bandwidth) it returns bg_thresh for wb1 as 0.5G although it has nobody to compete against in cgroup1. Fix the problem by calculating wb's share of bg_thresh in the cgroup domain. Test as following: /* make it easier to observe the issue */ echo 300000 > /proc/sys/vm/dirty_expire_centisecs echo 100 > /proc/sys/vm/dirty_writeback_centisecs /* run fio in wb1 */ cd /sys/fs/cgroup echo "+memory +io" > cgroup.subtree_control mkdir group1 cd group1 echo 10G > memory.high echo 10G > memory.max echo $$ > cgroup.procs mkfs.ext4 -F /dev/vdb mount /dev/vdb /bdi1/ fio -name test -filename=/bdi1/file -size=600M -ioengine=libaio -bs=4K \ -iodepth=1 -rw=write -direct=0 --time_based -runtime=600 -invalidate=0 /* run fio in wb2 with a new shell */ cd /sys/fs/cgroup mkdir group2 cd group2 echo 10G > memory.high echo 10G > memory.max echo $$ > cgroup.procs mkfs.ext4 -F /dev/vdc mount /dev/vdc /bdi2/ fio -name test -filename=/bdi2/file -size=600M -ioengine=libaio -bs=4K \ -iodepth=1 -rw=write -direct=0 --time_based -runtime=600 -invalidate=0 Before fix, the wrttien pages of wb1 and wb2 reported from toos/writeback/wb_monitor.py keep growing. After fix, rare written pages are accumulated. There is no obvious change in fio result. [jack@suse.cz: changelog rewording] Link: https://lkml.kernel.org/r/20240425131724.36778-3-shikemeng@huaweicloud.com Fixes: 74d36944 ("writeback: Fix performance regression in wb_over_bg_thresh()") Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Howard Cochran <hcochran@kernelspring.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miklos Szeredi <mszeredi@redhat.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Kemeng Shi authored
Patch series "Fix and cleanups to page-writeback", v2. This series contains some random cleanups and a fix to correct calculation of wb's bg_thresh in cgroup domain. More details can be found respective patches. This patch (of 4): Originally, __wb_calc_thresh always calculate wb's share of dirty throttling threshold. By getting thresh of wb_domain from caller, __wb_calc_thresh could be used for both dirty throttling and dirty background threshold. This is a preparation to correct threshold calculation of wb in cgroup. Link: https://lkml.kernel.org/r/20240425131724.36778-1-shikemeng@huaweicloud.com Link: https://lkml.kernel.org/r/20240425131724.36778-2-shikemeng@huaweicloud.comSigned-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Howard Cochran <hcochran@kernelspring.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miklos Szeredi <mszeredi@redhat.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Kemeng Shi authored
Commit 8d92890b ("mm/writeback: discard NR_UNSTABLE_NFS, use NR_WRITEBACK instead") removed NR_UNSTABLE_NFS and nr_reclaimable only contains dirty page now. Rename nr_reclaimable to nr_dirty properly. Link: https://lkml.kernel.org/r/20240423034643.141219-6-shikemeng@huaweicloud.comSigned-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Brian Foster <bfoster@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: David Sterba <dsterba@suse.com> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Kemeng Shi authored
Add wb_monitor.py script to monitor writeback information on backing dev which makes it easier and more convenient to observe writeback behaviors of running system. The wb_monitor.py script is written based on wq_monitor.py. Following domain hierarchy is tested: global domain (320G) / \ cgroup domain1(10G) cgroup domain2(10G) | | bdi wb1 wb2 The wb_monitor.py script output is as following: ./wb_monitor.py 252:16 -c writeback reclaimable dirtied written avg_bw 252:16_1 0 0 0 0 102400 252:16_4284 672 820064 9230368 8410304 685612 252:16_4325 896 819840 10491264 9671648 652348 252:16 1568 1639904 19721632 18081952 1440360 writeback reclaimable dirtied written avg_bw 252:16_1 0 0 0 0 102400 252:16_4284 672 820064 9230368 8410304 685612 252:16_4325 896 819840 10491264 9671648 652348 252:16 1568 1639904 19721632 18081952 1440360 ... Link: https://lkml.kernel.org/r/20240423034643.141219-5-shikemeng@huaweicloud.comSigned-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Suggested-by: Tejun Heo <tj@kernel.org> Cc: Brian Foster <bfoster@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: David Sterba <dsterba@suse.com> Cc: Jan Kara <jack@suse.cz> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Kemeng Shi authored
Add /sys/kernel/debug/bdi/xxx/wb_stats to show per group writeback stats of bdi. Following domain hierarchy is tested: global domain (320G) / \ cgroup domain1(10G) cgroup domain2(10G) | | bdi wb1 wb2 /* per wb writeback info of bdi is collected */ cat wb_stats WbCgIno: 1 WbWriteback: 0 kB WbReclaimable: 0 kB WbDirtyThresh: 0 kB WbDirtied: 0 kB WbWritten: 0 kB WbWriteBandwidth: 102400 kBps b_dirty: 0 b_io: 0 b_more_io: 0 b_dirty_time: 0 state: 1 WbCgIno: 4091 WbWriteback: 1792 kB WbReclaimable: 820512 kB WbDirtyThresh: 6004692 kB WbDirtied: 1820448 kB WbWritten: 999488 kB WbWriteBandwidth: 169020 kBps b_dirty: 0 b_io: 0 b_more_io: 1 b_dirty_time: 0 state: 5 WbCgIno: 4131 WbWriteback: 1120 kB WbReclaimable: 820064 kB WbDirtyThresh: 6004728 kB WbDirtied: 1822688 kB WbWritten: 1002400 kB WbWriteBandwidth: 153520 kBps b_dirty: 0 b_io: 0 b_more_io: 1 b_dirty_time: 0 state: 5 [shikemeng@huaweicloud.com: fix build problems] Link: https://lkml.kernel.org/r/20240423034643.141219-4-shikemeng@huaweicloud.com Link: https://lkml.kernel.org/r/20240423034643.141219-3-shikemeng@huaweicloud.comSigned-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Cc: Brian Foster <bfoster@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: David Sterba <dsterba@suse.com> Cc: Jan Kara <jack@suse.cz> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Kemeng Shi authored
Patch series "Improve visibility of writeback", v5. This series tries to improve visilibity of writeback. Patch 1 make /sys/kernel/debug/bdi/xxx/stats show writeback info of whole bdi instead of only writeback info in root cgroup. Patch 2 add a new debug file /sys/kernel/debug/bdi/xxx/wb_stats to show per wb writeback info. Patch 3 add wb_monitor.py to monitor basic writeback info of running system, more info could be added on demand. Patch 4 is a random cleanup. More details can be found in respective patches. Following domain hierarchy is tested: global domain (320G) / \ cgroup domain1(10G) cgroup domain2(10G) | | bdi wb1 wb2 /* all writeback info of bdi is successfully collected */ cat stats BdiWriteback: 4704 kB BdiReclaimable: 1294496 kB BdiDirtyThresh: 204208088 kB DirtyThresh: 195259944 kB BackgroundThresh: 32503588 kB BdiDirtied: 48519296 kB BdiWritten: 47225696 kB BdiWriteBandwidth: 1173892 kBps b_dirty: 1 b_io: 0 b_more_io: 1 b_dirty_time: 0 bdi_list: 1 state: 1 /* per wb writeback info of bdi is collected */ cat /sys/kernel/debug/bdi/252:16/wb_stats WbCgIno: 1 WbWriteback: 0 kB WbReclaimable: 0 kB WbDirtyThresh: 0 kB WbDirtied: 0 kB WbWritten: 0 kB WbWriteBandwidth: 102400 kBps b_dirty: 0 b_io: 0 b_more_io: 0 b_dirty_time: 0 state: 1 WbCgIno: 4208 WbWriteback: 59808 kB WbReclaimable: 676480 kB WbDirtyThresh: 6004624 kB WbDirtied: 23348192 kB WbWritten: 22614592 kB WbWriteBandwidth: 593204 kBps b_dirty: 1 b_io: 1 b_more_io: 0 b_dirty_time: 0 state: 7 WbCgIno: 4249 WbWriteback: 144256 kB WbReclaimable: 432096 kB WbDirtyThresh: 6004344 kB WbDirtied: 25727744 kB WbWritten: 25154752 kB WbWriteBandwidth: 577904 kBps b_dirty: 0 b_io: 1 b_more_io: 0 b_dirty_time: 0 state: 7 The wb_monitor.py script output is as following: ./wb_monitor.py 252:16 -c writeback reclaimable dirtied written avg_bw 252:16_1 0 0 0 0 102400 252:16_4284 672 820064 9230368 8410304 685612 252:16_4325 896 819840 10491264 9671648 652348 252:16 1568 1639904 19721632 18081952 1440360 writeback reclaimable dirtied written avg_bw 252:16_1 0 0 0 0 102400 252:16_4284 672 820064 9230368 8410304 685612 252:16_4325 896 819840 10491264 9671648 652348 252:16 1568 1639904 19721632 18081952 1440360 ... This patch (of 5): /sys/kernel/debug/bdi/xxx/stats is supposed to show writeback information of whole bdi, but only writeback information of bdi in root cgroup is collected. So writeback information in non-root cgroup are missing now. To be more specific, considering following case: /* create writeback cgroup */ cd /sys/fs/cgroup echo "+memory +io" > cgroup.subtree_control mkdir group1 cd group1 echo $$ > cgroup.procs /* do writeback in cgroup */ fio -name test -filename=/dev/vdb ... /* get writeback info of bdi */ cat /sys/kernel/debug/bdi/xxx/stats The cat result unexpectedly implies that there is no writeback on target bdi. Fix this by collecting stats of all wb in bdi instead of only wb in root cgroup. Following domain hierarchy is tested: global domain (320G) / \ cgroup domain1(10G) cgroup domain2(10G) | | bdi wb1 wb2 /* all writeback info of bdi is successfully collected */ cat stats BdiWriteback: 2912 kB BdiReclaimable: 1598464 kB BdiDirtyThresh: 167479028 kB DirtyThresh: 195038532 kB BackgroundThresh: 32466728 kB BdiDirtied: 19141696 kB BdiWritten: 17543456 kB BdiWriteBandwidth: 1136172 kBps b_dirty: 2 b_io: 0 b_more_io: 1 b_dirty_time: 0 bdi_list: 1 state: 1 Link: https://lkml.kernel.org/r/20240423034643.141219-1-shikemeng@huaweicloud.com Link: https://lkml.kernel.org/r/20240423034643.141219-2-shikemeng@huaweicloud.comSigned-off-by: Kemeng Shi <shikemeng@huaweicloud.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: Brian Foster <bfoster@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: David Sterba <dsterba@suse.com> Cc: Jan Kara <jack@suse.cz> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Ryan Roberts authored
Previously soft-dirty was unconditionally exiting with success, even if one of its testcases failed. Let's fix that so that failure can be reported to automated systems properly. Link: https://lkml.kernel.org/r/20240424105301.3157695-1-ryan.roberts@arm.comSigned-off-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Hariom Panthi authored
In vmap_pte_range, BUG_ON is called when page is already mapped, It doesn't give enough information to debug further. Dumping page owner information alongwith BUG_ON will be more useful in case of multiple page mapping. Example: [ 14.552875] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10b923 [ 14.553440] flags: 0xbffff0000000000(node=0|zone=2|lastcpupid=0x3ffff) [ 14.554001] page_type: 0xffffffff() [ 14.554783] raw: 0bffff0000000000 0000000000000000 dead000000000122 0000000000000000 [ 14.555230] raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 [ 14.555768] page dumped because: remapping already mapped page [ 14.556172] page_owner tracks the page as allocated [ 14.556482] page last allocated via order 0, migratetype Unmovable, gfp_mask 0xcc0(GFP_KERNEL), pid 80, tgid 80 (insmod), ts 14552004992, free_ts 0 [ 14.557286] prep_new_page+0xa8/0x10c [ 14.558052] get_page_from_freelist+0x7f8/0x1248 [ 14.558298] __alloc_pages+0x164/0x2b4 [ 14.558514] alloc_pages_mpol+0x88/0x230 [ 14.558904] alloc_pages+0x4c/0x7c [ 14.559157] load_module+0x74/0x1af4 [ 14.559361] __do_sys_init_module+0x190/0x1fc [ 14.559615] __arm64_sys_init_module+0x1c/0x28 [ 14.559883] invoke_syscall+0x44/0x108 [ 14.560109] el0_svc_common.constprop.0+0x40/0xe0 [ 14.560371] do_el0_svc_compat+0x1c/0x34 [ 14.560600] el0_svc_compat+0x2c/0x80 [ 14.560820] el0t_32_sync_handler+0x90/0x140 [ 14.561040] el0t_32_sync+0x194/0x198 [ 14.561329] page_owner free stack trace missing [ 14.562049] ------------[ cut here ]------------ [ 14.562314] kernel BUG at mm/vmalloc.c:113! Link: https://lkml.kernel.org/r/20240424111838.3782931-2-hariom1.p@samsung.comSigned-off-by: Hariom Panthi <hariom1.p@samsung.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Maninder Singh <maninder1.s@samsung.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Rohit Thapliyal <r.thapliyal@samsung.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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David Hildenbrand authored
We want to limit the use of page_mapcount() to places where absolutely required, to prepare for kernel configs where we won't keep track of per-page mapcounts in large folios. khugepaged is one of the remaining "more challenging" page_mapcount() users, but we might be able to move away from page_mapcount() without resulting in a significant behavior change that would warrant special-casing based on kernel configs. In 2020, we first added support to khugepaged for collapsing COW-shared pages via commit 9445689f ("khugepaged: allow to collapse a page shared across fork"), followed by support for collapsing PTE-mapped THP in commit 5503fbf2 ("khugepaged: allow to collapse PTE-mapped compound pages") and limiting the memory waste via the "page_count() > 1" check in commit 71a2c112 ("khugepaged: introduce 'max_ptes_shared' tunable"). As a default, khugepaged will allow up to half of the PTEs to map shared pages: where page_mapcount() > 1. MADV_COLLAPSE ignores the khugepaged setting. khugepaged does currently not care about swapcache page references, and does not check under folio lock: so in some corner cases the "shared vs. exclusive" detection might be a bit off, making us detect "exclusive" when it's actually "shared". Most of our anonymous folios in the system are usually exclusive. We frequently see sharing of anonymous folios for a short period of time, after which our short-lived suprocesses either quit or exec(). There are some famous examples, though, where child processes exist for a long time, and where memory is COW-shared with a lot of processes (webservers, webbrowsers, sshd, ...) and COW-sharing is crucial for reducing the memory footprint. We don't want to suddenly change the behavior to result in a significant increase in memory waste. Interestingly, khugepaged will only collapse an anonymous THP if at least one PTE is writable. After fork(), that means that something (usually a page fault) populated at least a single exclusive anonymous THP in that PMD range. So ... what happens when we switch to "is this folio mapped shared" instead of "is this page mapped shared" by using folio_likely_mapped_shared()? For "not-COW-shared" folios, small folios and for THPs (large folios) that are completely mapped into at least one process, switching to folio_likely_mapped_shared() will not result in a change. We'll only see a change for COW-shared PTE-mapped THPs that are partially mapped into all involved processes. There are two cases to consider: (A) folio_likely_mapped_shared() returns "false" for a PTE-mapped THP If the folio is detected as exclusive, and it actually is exclusive, there is no change: page_mapcount() == 1. This is the common case without fork() or with short-lived child processes. folio_likely_mapped_shared() might currently still detect a folio as exclusive although it is shared (false negatives): if the first page is not mapped multiple times and if the average per-page mapcount is smaller than 1, implying that (1) the folio is partially mapped and (2) if we are responsible for many mapcounts by mapping many pages others can't ("mostly exclusive") (3) if we are not responsible for many mapcounts by mapping little pages ("mostly shared") it won't make a big impact on the end result. So while we might now detect a page as "exclusive" although it isn't, it's not expected to make a big difference in common cases. (B) folio_likely_mapped_shared() returns "true" for a PTE-mapped THP folio_likely_mapped_shared() will never detect a large anonymous folio as shared although it is exclusive: there are no false positives. If we detect a THP as shared, at least one page of the THP is mapped by another process. It could well be that some pages are actually exclusive. For example, our child processes could have unmapped/COW'ed some pages such that they would now be exclusive to out process, which we now would treat as still-shared. Examples: (1) Parent maps all pages of a THP, child maps some pages. We detect all pages in the parent as shared although some are actually exclusive. (2) Parent maps all but some page of a THP, child maps the remainder. We detect all pages of the THP that the parent maps as shared although they are all exclusive. In (1) we wouldn't collapse a THP right now already: no PTE is writable, because a write fault would have resulted in COW of a single page and the parent would no longer map all pages of that THP. For (2) we would have collapsed a THP in the parent so far, now we wouldn't as long as the child process is still alive: unless the child process unmaps the remaining THP pages or we decide to split that THP. Possibly, the child COW'ed many pages, meaning that it's likely that we can populate a THP for our child first, and then for our parent. For (2), we are making really bad use of the THP in the first place (not even mapped completely in at least one process). If the THP would be completely partially mapped, it would be on the deferred split queue where we would split it lazily later. For short-running child processes, we don't particularly care. For long-running processes, the expectation is that such scenarios are rather rare: further, a THP might be best placed if most data in the PMD range is actually written, implying that we'll have to COW more pages first before khugepaged would collapse it. To summarize, in the common case, this change is not expected to matter much. The more common application of khugepaged operates on exclusive pages, either before fork() or after a child quit. Can we improve (A)? Yes, if we implement more precise tracking of "mapped shared" vs. "mapped exclusively", we could get rid of the false negatives completely. Can we improve (B)? We could count how many pages of a large folio we map inside the current page table and detect that we are responsible for most of the folio mapcount and conclude "as good as exclusive", which might help in some cases. ... but likely, some other mechanism should detect that the THP is not a good use in the scenario (not even mapped completely in a single process) and try splitting that folio lazily etc. We'll move the folio_test_anon() check before our "shared" check, so we might get more expressive results for SCAN_EXCEED_SHARED_PTE: this order of checks now matches the one in __collapse_huge_page_isolate(). Extend documentation. Link: https://lkml.kernel.org/r/20240424122630.495788-1-david@redhat.comSigned-off-by: David Hildenbrand <david@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Breno Leitao authored
A data-race issue in memcg rstat occurs when two distinct code paths access the same 4-byte region concurrently. KCSAN detection triggers the following BUG as a result. BUG: KCSAN: data-race in __count_memcg_events / mem_cgroup_css_rstat_flush write to 0xffffe8ffff98e300 of 4 bytes by task 5274 on cpu 17: mem_cgroup_css_rstat_flush (mm/memcontrol.c:5850) cgroup_rstat_flush_locked (kernel/cgroup/rstat.c:243 (discriminator 7)) cgroup_rstat_flush (./include/linux/spinlock.h:401 kernel/cgroup/rstat.c:278) mem_cgroup_flush_stats.part.0 (mm/memcontrol.c:767) memory_numa_stat_show (mm/memcontrol.c:6911) <snip> read to 0xffffe8ffff98e300 of 4 bytes by task 410848 on cpu 27: __count_memcg_events (mm/memcontrol.c:725 mm/memcontrol.c:962) count_memcg_event_mm.part.0 (./include/linux/memcontrol.h:1097 ./include/linux/memcontrol.h:1120) handle_mm_fault (mm/memory.c:5483 mm/memory.c:5622) <snip> value changed: 0x00000029 -> 0x00000000 The race occurs because two code paths access the same "stats_updates" location. Although "stats_updates" is a per-CPU variable, it is remotely accessed by another CPU at cgroup_rstat_flush_locked()->mem_cgroup_css_rstat_flush(), leading to the data race mentioned. Considering that memcg_rstat_updated() is in the hot code path, adding a lock to protect it may not be desirable, especially since this variable pertains solely to statistics. Therefore, annotating accesses to stats_updates with READ/WRITE_ONCE() can prevent KCSAN splats and potential partial reads/writes. Link: https://lkml.kernel.org/r/20240424125940.2410718-1-leitao@debian.org Fixes: 9cee7e8e ("mm: memcg: optimize parent iteration in memcg_rstat_updated()") Signed-off-by: Breno Leitao <leitao@debian.org> Suggested-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Yosry Ahmed <yosryahmed@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
All callers now use folio_*_referenced() so we can remove the PageReferenced family of functions. Link: https://lkml.kernel.org/r/20240424191914.361554-8-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
Convert the existing documentation to kernel-doc and remove references to pages. Link: https://lkml.kernel.org/r/20240424191914.361554-7-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
Use try_grab_folio() instead of try_grab_page() so we get the folio back that we calculated, and then use folio_set_referenced() instead of SetPageReferenced(). Correspondingly, use gup_put_folio() to put any unneeded references. Link: https://lkml.kernel.org/r/20240424191914.361554-6-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
With all callers converted to folios, we can act directly on folio->_refcount. Link: https://lkml.kernel.org/r/20240424191914.361554-5-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
All callers have a folio so we can remove this use of page_ref_sub_return(). Link: https://lkml.kernel.org/r/20240424191914.361554-4-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
It only has one caller; convert that caller to use put_devmap_managed_page_refs() instead. Link: https://lkml.kernel.org/r/20240424191914.361554-3-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
Patch series "More folio compat code removal". More code removal with bonus kernel-doc addition. This patch (of 7): All callers have now been converted to filemap_alloc_folio(). Link: https://lkml.kernel.org/r/20240424191914.361554-1-willy@infradead.org Link: https://lkml.kernel.org/r/20240424191914.361554-2-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
Call page_folio() a little earlier so we can use folio_mapping() instead of page_mapping(), saving a call to compound_head(). Link: https://lkml.kernel.org/r/20240423225552.4113447-6-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
Removes a few calls to compound_head() and a call to page_mapping(). Link: https://lkml.kernel.org/r/20240423225552.4113447-5-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
This is mostly just inlining page_mapping() into the two callers. Link: https://lkml.kernel.org/r/20240423225552.4113447-4-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Eric Biggers <ebiggers@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
Removes uses of page_mapping() and page_index(). Link: https://lkml.kernel.org/r/20240423225552.4113447-3-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
Patch series "Remove page_mapping()". There are only a few users left. Convert them all to either call folio_mapping() or just use folio->mapping directly. This patch (of 6): Remove uses of page->index, page_mapping() and b_page. Saves a call to compound_head(). Link: https://lkml.kernel.org/r/20240423225552.4113447-1-willy@infradead.org Link: https://lkml.kernel.org/r/20240423225552.4113447-2-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Eric Biggers <ebiggers@google.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
We've already calculated it, so pass it in instead of recalculating it in collect_procs_ksm(). Link: https://lkml.kernel.org/r/20240412193510.2356957-12-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
Saves a couple of calls to compound_head(). Link: https://lkml.kernel.org/r/20240412193510.2356957-11-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Jane Chu <jane.chu@oracle.com> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
Some of these folio APIs didn't exist when the unpoison_memory() conversion was done originally. Link: https://lkml.kernel.org/r/20240412193510.2356957-10-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Jane Chu <jane.chu@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
Pass the folio from the callers, and use it throughout instead of hpage. Saves dozens of calls to compound_head(). Link: https://lkml.kernel.org/r/20240412193510.2356957-9-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Jane Chu <jane.chu@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
Saves dozens of calls to compound_head(). Link: https://lkml.kernel.org/r/20240412193510.2356957-8-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
The page is only used to get the mapping, so the folio will do just as well. Both callers already have a folio available, so this saves a call to compound_head(). Link: https://lkml.kernel.org/r/20240412193510.2356957-7-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
Removes two calls to compound_head(). Move the prototype to internal.h; we definitely don't want code outside mm using it. Link: https://lkml.kernel.org/r/20240412193510.2356957-6-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Jane Chu <jane.chu@oracle.com> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
This function is only currently used by the memory-failure code, so we can omit it if we're not compiling in the memory-failure code. Link: https://lkml.kernel.org/r/20240412193510.2356957-5-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Suggested-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
The only user of this function calls page_address_in_vma() immediately after page_mapped_in_vma() calculates it and uses it to return true/false. Return the address instead, allowing memory-failure to skip the call to page_address_in_vma(). Link: https://lkml.kernel.org/r/20240412193510.2356957-4-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Jane Chu <jane.chu@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
Handle anon/file folios the same way as KSM & DAX folios by passing in the address. Link: https://lkml.kernel.org/r/20240412193510.2356957-3-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
Patch series "Some cleanups for memory-failure", v3. A lot of folio conversions, plus some other simplifications. This patch (of 11): Unify the KSM and DAX codepaths by calculating the addr in add_to_kill_fsdax() instead of telling __add_to_kill() to calculate it. Link: https://lkml.kernel.org/r/20240412193510.2356957-1-willy@infradead.org Link: https://lkml.kernel.org/r/20240412193510.2356957-2-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Andy Shevchenko authored
Update header inclusions to follow IWYU (Include What You Use) principle. Link: https://lkml.kernel.org/r/20240423142204.2408923-3-andriy.shevchenko@linux.intel.comSigned-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Andy Shevchenko authored
Patch series "xarray: Clean up xarray.h". Main portion of this change is to get rid of kernel.h included into other globally available headers. This decreases a dependency hell degree. The first patch makes it possible to avoid math.h to be included as bitops.h is implied by bitmap.h. This patch (of 2): Use BITS_PER_LONGS() instead of open coded variant. Link: https://lkml.kernel.org/r/20240423142204.2408923-2-andriy.shevchenko@linux.intel.comSigned-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Shakeel Butt authored
mod_memcg_lruvec_state() is never called from outside of memcontrol.c and with always irq disabled. So, replace it with the irq disabled version and add an assert that irq is disabled in the caller. Similarly mod_objcg_state() is not called from outside of memcontrol.c, so simply make it static and change it's name to __mod_objcg_state(). Link: https://lkml.kernel.org/r/20240420232505.2768428-1-shakeel.butt@linux.devSigned-off-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: T.J. Mercier <tjmercier@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Kefeng Wang authored
Add userfaultfd_wp() check in vmf_orig_pte_uffd_wp() to avoid the unnecessary FAULT_FLAG_ORIG_PTE_VALID check/pte_marker_entry_uffd_wp() in most pagefault, note, the function vmf_orig_pte_uffd_wp() is not inlined in the two kernel versions, the difference is shown below, perf date, perf report -i perf.data.before | grep vmf 0.17% 0.13% lat_pagefault [kernel.kallsyms] [k] vmf_orig_pte_uffd_wp.part.0.isra.0 perf report -i perf.data.after | grep vmf lat_pagefault -W 5 -N 5 /tmp/XXX latency before after diff average(8 tests) 0.262675 0.2600375 -0.0026375 Although it's a small, but the uffd_wp is a new feature than previous kernel, when the vma is not registered with UFFD_WP, let's avoid to execute the new logical, also adding __always_inline attribute to vmf_orig_pte_uffd_wp(), which make set_pte_range() only check VM_UFFD_WP flags without the function call. In addition, directly call the vmf_orig_pte_uffd_wp() in do_anonymous_page() and set_pte_range() to save an uffd_wp variable. Link: https://lkml.kernel.org/r/20240422030039.3293568-1-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Hao Ge authored
Make PageUptodate return bool to align the return values of folio_test_uptodate function Link: https://lkml.kernel.org/r/20240422032725.41452-1-gehao@kylinos.cnSigned-off-by: Hao Ge <gehao@kylinos.cn> Cc: David Hildenbrand <david@redhat.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Ruihan Li <lrh2000@pku.edu.cn> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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