- 12 Sep, 2022 40 commits
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Miaohe Lin authored
Use helper macro SZ_1K to do the size conversion to make code more consistent in this file. Minor readability improvement. Link: https://lkml.kernel.org/r/20220901120030.63318-3-linmiaohe@huawei.comSigned-off-by:
Miaohe Lin <linmiaohe@huawei.com> Reviewed-by:
Muchun Song <songmuchun@bytedance.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>
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Miaohe Lin authored
Patch series "A few cleanup patches for hugetlb", v2. This series contains a few cleanup patches to use helper functions to simplify the codes, remove unneeded nid parameter and so on. More details can be found in the respective changelogs. This patch (of 10): Make hugetlb_cma_check() static as it's only used inside mm/hugetlb.c. Link: https://lkml.kernel.org/r/20220901120030.63318-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20220901120030.63318-2-linmiaohe@huawei.comSigned-off-by:
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Zhang Yi authored
bh_submit_read() has no user anymore, just remove it. Link: https://lkml.kernel.org/r/20220901133505.2510834-15-yi.zhang@huawei.comSigned-off-by:
Zhang Yi <yi.zhang@huawei.com> Reviewed-by:
Jan Kara <jack@suse.cz> Reviewed-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
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Zhang Yi authored
bh_submit_read() and the uptodate check logic in bh_uptodate_or_lock() has been integrated in bh_read() helper, so switch to use it directly. Link: https://lkml.kernel.org/r/20220901133505.2510834-14-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
Now that all ll_rw_block() users has been replaced to new safe helpers, we just remove it here. Link: https://lkml.kernel.org/r/20220901133505.2510834-13-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read path because it cannot guarantee that submitting read IO if the buffer has been locked. We could get false positive EIO after wait_on_buffer() if the buffer has been locked by others. So stop using ll_rw_block() in ufs. Link: https://lkml.kernel.org/r/20220901133505.2510834-12-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read path because it cannot guarantee that submitting read IO if the buffer has been locked. We could get false positive EIO after wait_on_buffer() if the buffer has been locked by others. So stop using ll_rw_block(). We also switch to new bh_readahead_batch() helper for the buffer array readahead path. Link: https://lkml.kernel.org/r/20220901133505.2510834-11-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read/write path because it cannot guarantee that submitting read/write IO if the buffer has been locked. We could get false positive EIO after wait_on_buffer() in read path if the buffer has been locked by others. So stop using ll_rw_block() in reiserfs. We also switch to new bh_readahead_batch() helper for the buffer array readahead path. Link: https://lkml.kernel.org/r/20220901133505.2510834-10-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read path because it cannot guarantee that submitting read IO if the buffer has been locked. We could get false positive EIO after wait_on_buffer() if the buffer has been locked by others. So stop using ll_rw_block() in ocfs2. Link: https://lkml.kernel.org/r/20220901133505.2510834-9-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read path because it cannot guarantee that submitting read IO if the buffer has been locked. We could get false positive EIO after wait_on_buffer() if the buffer has been locked by others. So stop using ll_rw_block() in ntfs_get_block_vbo(). Link: https://lkml.kernel.org/r/20220901133505.2510834-8-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read path because it cannot guarantee that submitting read IO if the buffer has been locked. We could get false positive EIO after wait_on_buffer() if the buffer has been locked by others. So stop using ll_rw_block() in journal_get_superblock(). We also switch to new bh_readahead_batch() for the buffer array readahead path. Link: https://lkml.kernel.org/r/20220901133505.2510834-7-yi.zhang@huawei.comSigned-off-by:
Theodore Ts'o <tytso@mit.edu> Reviewed-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read path because it cannot guarantee that submitting read IO if the buffer has been locked. We could get false positive EIO return from zisofs_uncompress_block() if he buffer has been locked by others. So stop using ll_rw_block(), switch to sync helper instead. Link: https://lkml.kernel.org/r/20220901133505.2510834-6-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync read path because it cannot guarantee that always submitting read IO if the buffer has been locked, so stop using it. We also switch to new bh_readahead() helper for the readahead path. Link: https://lkml.kernel.org/r/20220901133505.2510834-5-yi.zhang@huawei.comSigned-off-by:
Andreas Gruenbacher <agruenba@redhat.com> Reviewed-by:
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Zhang Yi authored
ll_rw_block() is not safe for the sync IO path because it skip buffers which has been locked by others, it could lead to false positive EIO when submitting read IO. So stop using ll_rw_block(), switch to use new helpers which could guarantee buffer locked and submit IO if needed. Link: https://lkml.kernel.org/r/20220901133505.2510834-4-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
Current ll_rw_block() helper is fragile because it assumes that locked buffer means it's under IO which is submitted by some other who holds the lock, it skip buffer if it failed to get the lock, so it's only safe on the readahead path. Unfortunately, now that most filesystems still use this helper mistakenly on the sync metadata read path. There is no guarantee that the one who holds the buffer lock always submit IO (e.g. buffer_migrate_folio_norefs() after commit 88dbcbb3 ("blkdev: avoid migration stalls for blkdev pages"), it could lead to false positive -EIO when submitting reading IO. This patch add some friendly buffer read helpers to prepare replacing ll_rw_block() and similar calls. We can only call bh_readahead_[] helpers for the readahead paths. Link: https://lkml.kernel.org/r/20220901133505.2510834-3-yi.zhang@huawei.comSigned-off-by:
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Zhang Yi authored
Patch series "fs/buffer: remove ll_rw_block()", v2. ll_rw_block() will skip locked buffer before submitting IO, it assumes that locked buffer means it is under IO. This assumption is not always true because we cannot guarantee every buffer lock path would submit IO. After commit 88dbcbb3 ("blkdev: avoid migration stalls for blkdev pages"), buffer_migrate_folio_norefs() becomes one exceptional case, and there may be others. So ll_rw_block() is not safe on the sync read path, we could get false positive EIO return value when filesystem reading metadata. It seems that it could be only used on the readahead path. Unfortunately, many filesystem misuse the ll_rw_block() on the sync read path. This patch set just remove ll_rw_block() and add new friendly helpers, which could prevent false positive EIO on the read metadata path. Thanks for the suggestion from Jan, the original discussion is at [1]. patch 1: remove unused helpers in fs/buffer.c patch 2: add new bh_read_[*] helpers patch 3-11: remove all ll_rw_block() calls in filesystems patch 12-14: do some leftover cleanups. [1]. https://lore.kernel.org/linux-mm/20220825080146.2021641-1-chengzhihao1@huawei.com/ This patch (of 14): No one use __breadahead_gfp() and sb_breadahead_unmovable() any more, remove them. Link: https://lkml.kernel.org/r/20220901133505.2510834-1-yi.zhang@huawei.com Link: https://lkml.kernel.org/r/20220901133505.2510834-2-yi.zhang@huawei.comSigned-off-by:
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Song Liu authored
find_vmap_lowest_match() is now able to handle different roots. With DEBUG_AUGMENT_LOWEST_MATCH_CHECK enabled as: : --- a/mm/vmalloc.c : +++ b/mm/vmalloc.c : @@ -713,7 +713,7 @@ EXPORT_SYMBOL(vmalloc_to_pfn); : /*** Global kva allocator ***/ : : -#define DEBUG_AUGMENT_LOWEST_MATCH_CHECK 0 : +#define DEBUG_AUGMENT_LOWEST_MATCH_CHECK 1 compilation failed as: mm/vmalloc.c: In function 'find_vmap_lowest_match_check': mm/vmalloc.c:1328:32: warning: passing argument 1 of 'find_vmap_lowest_match' makes pointer from integer without a cast [-Wint-conversion] 1328 | va_1 = find_vmap_lowest_match(size, align, vstart, false); | ^~~~ | | | long unsigned int mm/vmalloc.c:1236:40: note: expected 'struct rb_root *' but argument is of type 'long unsigned int' 1236 | find_vmap_lowest_match(struct rb_root *root, unsigned long size, | ~~~~~~~~~~~~~~~~^~~~ mm/vmalloc.c:1328:9: error: too few arguments to function 'find_vmap_lowest_match' 1328 | va_1 = find_vmap_lowest_match(size, align, vstart, false); | ^~~~~~~~~~~~~~~~~~~~~~ mm/vmalloc.c:1236:1: note: declared here 1236 | find_vmap_lowest_match(struct rb_root *root, unsigned long size, | ^~~~~~~~~~~~~~~~~~~~~~ Extend find_vmap_lowest_match_check() and find_vmap_lowest_linear_match() with extra arguments to fix this. Link: https://lkml.kernel.org/r/20220906060548.1127396-1-song@kernel.org Link: https://lkml.kernel.org/r/20220831052734.3423079-1-song@kernel.org Fixes: f9863be4 ("mm/vmalloc: extend __alloc_vmap_area() with extra arguments") Signed-off-by:Song Liu <song@kernel.org> Reviewed-by:
Baoquan He <bhe@redhat.com> Reviewed-by:
Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by:
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Alistair Popple authored
Commit ab09243a ("mm/migrate.c: remove MIGRATE_PFN_LOCKED") changed the way trylock_page() in migrate_vma_collect_pmd() works without updating the comment. Reword the comment to be less misleading and a better reflection of what happens. Link: https://lkml.kernel.org/r/20220830020138.497063-1-apopple@nvidia.com Fixes: ab09243a ("mm/migrate.c: remove MIGRATE_PFN_LOCKED") Signed-off-by:
Alistair Popple <apopple@nvidia.com> Reported-by:
Peter Xu <peterx@redhat.com> Acked-by:
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zezuo authored
The gfp_flags parameter is not used in rmqueue_pcplist, so directly delete this parameter. Link: https://lkml.kernel.org/r/20220831013404.3360714-1-zuoze1@huawei.comSigned-off-by:
zezuo <zuoze1@huawei.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by:
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Kaixu Xia authored
We can get the hotness value from damon_hot_score() directly in damon_pageout_score() function and improve the code readability. Link: https://lkml.kernel.org/r/1661766366-20998-1-git-send-email-kaixuxia@tencent.comSigned-off-by:
Kaixu Xia <kaixuxia@tencent.com> Reviewed-by:
SeongJae Park <sj@kernel.org> Signed-off-by:
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Liu Shixin authored
Simplify code by removing redundant CONFIG_TRANSPARENT_HUGEPAGE judgment. No functional change. Link: https://lkml.kernel.org/r/20220829095125.3284567-1-liushixin2@huawei.comSigned-off-by:
Liu Shixin <liushixin2@huawei.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by:
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Liu Shixin authored
Simplify code of has_transparent_hugepage define by using IS_BUILTIN. No functional change. Link: https://lkml.kernel.org/r/20220829095709.3287462-1-liushixin2@huawei.comSigned-off-by:
David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by:
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Kaixu Xia authored
The damon regions that belong to the same damon target have the same 'struct mm_struct *mm', so it's unnecessary to compare the mm and last_mm objects among the damon regions in one damon target when checking accesses. But the check is necessary when the target changed in '__damon_va_check_accesses()', so we can simplify the whole operation by using the bool 'same_target' to indicate whether the target changed. Link: https://lkml.kernel.org/r/1661590971-20893-3-git-send-email-kaixuxia@tencent.comSigned-off-by:
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Kaixu Xia authored
Patch series "mm/damon: Simplify the damon regions access check", v2. This patchset simplifies the operations when checking the damon regions accesses. This patch (of 2): The parameter 'struct damon_ctx *ctx' isn't used in the functions __damon_{p,v}a_check_access(), so we can remove it and simplify the parameter passing. Link: https://lkml.kernel.org/r/1661590971-20893-1-git-send-email-kaixuxia@tencent.com Link: https://lkml.kernel.org/r/1661590971-20893-2-git-send-email-kaixuxia@tencent.comSigned-off-by: -
Kefeng Wang authored
kswapd_run/stop() will set pgdat->kswapd to NULL, which could race with kswapd_is_running() in kcompactd(), kswapd_run/stop() kcompactd() kswapd_is_running() pgdat->kswapd // error or nomal ptr verify pgdat->kswapd // load non-NULL pgdat->kswapd pgdat->kswapd = NULL task_is_running(pgdat->kswapd) // Null pointer derefence KASAN reports the null-ptr-deref shown below, vmscan: Failed to start kswapd on node 0 ... BUG: KASAN: null-ptr-deref in kcompactd+0x440/0x504 Read of size 8 at addr 0000000000000024 by task kcompactd0/37 CPU: 0 PID: 37 Comm: kcompactd0 Kdump: loaded Tainted: G OE 5.10.60 #1 Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 Call trace: dump_backtrace+0x0/0x394 show_stack+0x34/0x4c dump_stack+0x158/0x1e4 __kasan_report+0x138/0x140 kasan_report+0x44/0xdc __asan_load8+0x94/0xd0 kcompactd+0x440/0x504 kthread+0x1a4/0x1f0 ret_from_fork+0x10/0x18 At present kswapd/kcompactd_run() and kswapd/kcompactd_stop() are protected by mem_hotplug_begin/done(), but without kcompactd(). There is no need to involve memory hotplug lock in kcompactd(), so let's add a new mutex to protect pgdat->kswapd accesses. Also, because the kcompactd task will check the state of kswapd task, it's better to call kcompactd_stop() before kswapd_stop() to reduce lock conflicts. [akpm@linux-foundation.org: add comments] Link: https://lkml.kernel.org/r/20220827111959.186838-1-wangkefeng.wang@huawei.comSigned-off-by:Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by:
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Kefeng Wang authored
Directly check state of struct memory_block, no need a single function. Link: https://lkml.kernel.org/r/20220827112043.187028-1-wangkefeng.wang@huawei.comSigned-off-by:
Oscar Salvador <osalvador@suse.de> Reviewed-by:
Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by:
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Vishal Moola (Oracle) authored
All callers of find_get_pages_contig() have been removed, so it is no longer needed. Link: https://lkml.kernel.org/r/20220824004023.77310-8-vishal.moola@gmail.comSigned-off-by:
Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <clm@fb.com> Cc: David Sterba <dsterba@suse.com> Cc: David Sterba <dsterb@suse.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com> Signed-off-by:
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Vishal Moola (Oracle) authored
Convert to use folios throughout. This is in preparation for the removal for find_get_pages_contig(). Now also supports large folios. The initial version of this function set the page_address to be returned after finishing all the checks. Since folio_batches have a maximum of 15 folios, the function had to be modified to support getting and checking up to lpages, 15 pages at a time while still returning the initial page address. Now the function sets ret as soon as the first batch arrives, and updates it only if a check fails. The physical adjacency check utilizes the page frame numbers. The page frame number of each folio must be nr_pages away from the first folio. Link: https://lkml.kernel.org/r/20220824004023.77310-7-vishal.moola@gmail.comSigned-off-by:
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Vishal Moola (Oracle) authored
Convert function to use folios throughout. This is in preparation for the removal of find_get_pages_contig(). Now also supports large folios. Also clean up an unnecessary if statement - pvec.pages[0]->index > index will always evaluate to false, and filemap_get_folios_contig() returns 0 if there is no folio found at index. Link: https://lkml.kernel.org/r/20220824004023.77310-6-vishal.moola@gmail.comSigned-off-by:
Ryusuke Konishi <konishi.ryusuke@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <clm@fb.com> Cc: David Sterba <dsterba@suse.com> Cc: David Sterba <dsterb@suse.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by:
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Vishal Moola (Oracle) authored
Converted function to use folios throughout. This is in preparation for the removal of find_get_pages_contig(). Now also supports large folios. Since we may receive more than nr_pages pages, nr_pages may underflow. Since nr_pages > 0 is equivalent to index <= end_index, we replaced it with this check instead. Also minor comment renaming for consistency in subpage. Link: https://lkml.kernel.org/r/20220824004023.77310-5-vishal.moola@gmail.comSigned-off-by:
David Sterba <dsterb@suse.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <clm@fb.com> Cc: David Sterba <dsterba@suse.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com> Signed-off-by:
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Vishal Moola (Oracle) authored
Converted function to use folios throughout. This is in preparation for the removal of find_get_pages_contig(). Now also supports large folios. Since we may receive more than nr_pages pages, nr_pages may underflow. Since nr_pages > 0 is equivalent to index <= end_index, we replaced it with this check instead. Also this function does not care about the pages being contiguous so we can just use filemap_get_folios() to be more efficient. Link: https://lkml.kernel.org/r/20220824004023.77310-4-vishal.moola@gmail.comSigned-off-by:
David Sterba <dsterba@suse.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <clm@fb.com> Cc: David Sterba <dsterb@suse.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com> Signed-off-by:
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Vishal Moola (Oracle) authored
Convert to use folios throughout. This is in preparation for the removal of find_get_pages_contig(). Now also supports large folios. Since we may receive more than nr_pages pages, nr_pages may underflow. Since nr_pages > 0 is equivalent to index <= end_index, we replaced it with this check instead. Link: https://lkml.kernel.org/r/20220824004023.77310-3-vishal.moola@gmail.comSigned-off-by:
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Vishal Moola (Oracle) authored
Patch series "Convert to filemap_get_folios_contig()", v3. This patch series replaces find_get_pages_contig() with filemap_get_folios_contig(). This patch (of 7): This function is meant to replace find_get_pages_contig(). Unlike find_get_pages_contig(), filemap_get_folios_contig() no longer takes in a target number of pages to find - It returns up to 15 contiguous folios. To be more consistent with filemap_get_folios(), filemap_get_folios_contig() now also updates the start index passed in, and takes an end index. Link: https://lkml.kernel.org/r/20220824004023.77310-1-vishal.moola@gmail.com Link: https://lkml.kernel.org/r/20220824004023.77310-2-vishal.moola@gmail.comSigned-off-by:
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Alexey Romanov authored
It doesn't make sense for us to retry to compress an uncompressible page (comp_len == PAGE_SIZE) in zsmalloc slowpath, because we will be storing it uncompressed anyway. We can avoid wasting time on another compression attempt. It is enough to take lock (zcomp_stream_get) and execute the code below. Link: https://lkml.kernel.org/r/20220824113117.78849-1-avromanov@sberdevices.ruSigned-off-by:
Alexey Romanov <avromanov@sberdevices.ru> Signed-off-by:
Dmitry Rokosov <ddrokosov@sberdevices.ru> Reviewed-by:
Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Alexey Romanov <avromanov@sberdevices.ru> Cc: Dmitry Rokosov <DDRokosov@sberdevices.ru> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by:
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ye xingchen authored
Return the value cgwb_bdi_init() directly instead of storing it in another redundant variable. Link: https://lkml.kernel.org/r/20220826071906.252419-1-ye.xingchen@zte.com.cnSigned-off-by:
ye xingchen <ye.xingchen@zte.com.cn> Reported-by:
Zeal Robot <zealci@zte.com.cn> Reviewed-by:
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Li Zhe authored
In commit 2f1ee091 ("Revert "mm: use early_pfn_to_nid in page_ext_init""), we call page_ext_init() after page_alloc_init_late() to avoid some panic problem. It seems that we cannot track early page allocations in current kernel even if page structure has been initialized early. This patch introduces a new boot parameter 'early_page_ext' to resolve this problem. If we pass it to the kernel, page_ext_init() will be moved up and the feature 'deferred initialization of struct pages' will be disabled to initialize the page allocator early and prevent the panic problem above. It can help us to catch early page allocations. This is useful especially when we find that the free memory value is not the same right after different kernel booting. [akpm@linux-foundation.org: fix section issue by removing __meminitdata] Link: https://lkml.kernel.org/r/20220825102714.669-1-lizhe.67@bytedance.comSigned-off-by:
Li Zhe <lizhe.67@bytedance.com> Suggested-by:
Michal Hocko <mhocko@suse.com> Acked-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: Mark-PK Tsai <mark-pk.tsai@mediatek.com> Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by:
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Gerald Schaefer authored
When pud-sized hugepages were introduced for s390, the generic version of follow_huge_pud() was using pte_page() instead of pud_page(). This would be wrong for s390, see also commit 97534127 ("mm/hugetlb: use pmd_page() in follow_huge_pmd()"). Therefore, and probably because not all archs were supporting pud_page() at that time, a private version of follow_huge_pud() was added for s390, correctly using pud_page(). Since commit 3a194f3f ("mm/hugetlb: make pud_huge() and follow_huge_pud() aware of non-present pud entry"), the generic version of follow_huge_pud() is now also using pud_page(), and in general behaves similar to follow_huge_pmd(). Therefore we can now switch to the generic version and get rid of the s390-specific follow_huge_pud(). Link: https://lkml.kernel.org/r/20220818135717.609eef8a@thinkpadSigned-off-by:
Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Haiyue Wang <haiyue.wang@intel.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: David Hildenbrand <david@redhat.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by:
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Shakeel Butt authored
For several years, MEMCG_CHARGE_BATCH was kept at 32 but with bigger machines and the network intensive workloads requiring througput in Gbps, 32 is too small and makes the memcg charging path a bottleneck. For now, increase it to 64 for easy acceptance to 6.0. We will need to revisit this in future for ever increasing demand of higher performance. Please note that the memcg charge path drain the per-cpu memcg charge stock, so there should not be any oom behavior change. Though it does have impact on rstat flushing and high limit reclaim backoff. To evaluate the impact of this optimization, on a 72 CPUs machine, we ran the following workload in a three level of cgroup hierarchy. $ netserver -6 # 36 instances of netperf with following params $ netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K Results (average throughput of netperf): Without (6.0-rc1) 10482.7 Mbps With patch 17064.7 Mbps (62.7% improvement) With the patch, the throughput improved by 62.7%. Link: https://lkml.kernel.org/r/20220825000506.239406-4-shakeelb@google.comSigned-off-by:
Shakeel Butt <shakeelb@google.com> Reported-by:
kernel test robot <oliver.sang@intel.com> Acked-by:
Soheil Hassas Yeganeh <soheil@google.com> Reviewed-by:
Feng Tang <feng.tang@intel.com> Acked-by:
Roman Gushchin <roman.gushchin@linux.dev> Acked-by:
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Shakeel Butt authored
With memcg v2 enabled, memcg->memory.usage is a very hot member for the workloads doing memcg charging on multiple CPUs concurrently. Particularly the network intensive workloads. In addition, there is a false cache sharing between memory.usage and memory.high on the charge path. This patch moves the usage into a separate cacheline and move all the read most fields into separate cacheline. To evaluate the impact of this optimization, on a 72 CPUs machine, we ran the following workload in a three level of cgroup hierarchy. $ netserver -6 # 36 instances of netperf with following params $ netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K Results (average throughput of netperf): Without (6.0-rc1) 10482.7 Mbps With patch 12413.7 Mbps (18.4% improvement) With the patch, the throughput improved by 18.4%. One side-effect of this patch is the increase in the size of struct mem_cgroup. For example with this patch on 64 bit build, the size of struct mem_cgroup increased from 4032 bytes to 4416 bytes. However for the performance improvement, this additional size is worth it. In addition there are opportunities to reduce the size of struct mem_cgroup like deprecation of kmem and tcpmem page counters and better packing. Link: https://lkml.kernel.org/r/20220825000506.239406-3-shakeelb@google.comSigned-off-by:
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Shakeel Butt authored
Patch series "memcg: optimize charge codepath", v2. Recently Linux networking stack has moved from a very old per socket pre-charge caching to per-cpu caching to avoid pre-charge fragmentation and unwarranted OOMs. One impact of this change is that for network traffic workloads, memcg charging codepath can become a bottleneck. The kernel test robot has also reported this regression[1]. This patch series tries to improve the memcg charging for such workloads. This patch series implement three optimizations: (A) Reduce atomic ops in page counter update path. (B) Change layout of struct page_counter to eliminate false sharing between usage and high. (C) Increase the memcg charge batch to 64. To evaluate the impact of these optimizations, on a 72 CPUs machine, we ran the following workload in root memcg and then compared with scenario where the workload is run in a three level of cgroup hierarchy with top level having min and low setup appropriately. $ netserver -6 # 36 instances of netperf with following params $ netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K Results (average throughput of netperf): 1. root memcg 21694.8 Mbps 2. 6.0-rc1 10482.7 Mbps (-51.6%) 3. 6.0-rc1 + (A) 14542.5 Mbps (-32.9%) 4. 6.0-rc1 + (B) 12413.7 Mbps (-42.7%) 5. 6.0-rc1 + (C) 17063.7 Mbps (-21.3%) 6. 6.0-rc1 + (A+B+C) 20120.3 Mbps (-7.2%) With all three optimizations, the memcg overhead of this workload has been reduced from 51.6% to just 7.2%. [1] https://lore.kernel.org/linux-mm/20220619150456.GB34471@xsang-OptiPlex-9020/ This patch (of 3): For cgroups using low or min protections, the function propagate_protected_usage() was doing an atomic xchg() operation irrespectively. We can optimize out this atomic operation for one specific scenario where the workload is using the protection (i.e. min > 0) and the usage is above the protection (i.e. usage > min). This scenario is actually very common where the users want a part of their workload to be protected against the external reclaim. Though this optimization does introduce a race when the usage is around the protection and concurrent charges and uncharged trip it over or under the protection. In such cases, we might see lower effective protection but the subsequent charge/uncharge will correct it. To evaluate the impact of this optimization, on a 72 CPUs machine, we ran the following workload in a three level of cgroup hierarchy with top level having min and low setup appropriately to see if this optimization is effective for the mentioned case. $ netserver -6 # 36 instances of netperf with following params $ netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K Results (average throughput of netperf): Without (6.0-rc1) 10482.7 Mbps With patch 14542.5 Mbps (38.7% improvement) With the patch, the throughput improved by 38.7% Link: https://lkml.kernel.org/r/20220825000506.239406-1-shakeelb@google.com Link: https://lkml.kernel.org/r/20220825000506.239406-2-shakeelb@google.comSigned-off-by:
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