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2022-09-27mm: multi-gen LRU: optimize multiple memcgsYu Zhao1-9/+96
When multiple memcgs are available, it is possible to use generations as a frame of reference to make better choices and improve overall performance under global memory pressure. This patch adds a basic optimization to select memcgs that can drop single-use unmapped clean pages first. Doing so reduces the chance of going into the aging path or swapping, which can be costly. A typical example that benefits from this optimization is a server running mixed types of workloads, e.g., heavy anon workload in one memcg and heavy buffered I/O workload in the other. Though this optimization can be applied to both kswapd and direct reclaim, it is only added to kswapd to keep the patchset manageable. Later improvements may cover the direct reclaim path. While ensuring certain fairness to all eligible memcgs, proportional scans of individual memcgs also require proper backoff to avoid overshooting their aggregate reclaim target by too much. Otherwise it can cause high direct reclaim latency. The conditions for backoff are: 1. At low priorities, for direct reclaim, if aging fairness or direct reclaim latency is at risk, i.e., aging one memcg multiple times or swapping after the target is met. 2. At high priorities, for global reclaim, if per-zone free pages are above respective watermarks. Server benchmark results: Mixed workloads: fio (buffered I/O): +[19, 21]% IOPS BW patch1-8: 1880k 7343MiB/s patch1-9: 2252k 8796MiB/s memcached (anon): +[119, 123]% Ops/sec KB/sec patch1-8: 862768.65 33514.68 patch1-9: 1911022.12 74234.54 Mixed workloads: fio (buffered I/O): +[75, 77]% IOPS BW 5.19-rc1: 1279k 4996MiB/s patch1-9: 2252k 8796MiB/s memcached (anon): +[13, 15]% Ops/sec KB/sec 5.19-rc1: 1673524.04 65008.87 patch1-9: 1911022.12 74234.54 Configurations: (changes since patch 6) cat mixed.sh modprobe brd rd_nr=2 rd_size=56623104 swapoff -a mkswap /dev/ram0 swapon /dev/ram0 mkfs.ext4 /dev/ram1 mount -t ext4 /dev/ram1 /mnt memtier_benchmark -S /var/run/memcached/memcached.sock \ -P memcache_binary -n allkeys --key-minimum=1 \ --key-maximum=50000000 --key-pattern=P:P -c 1 -t 36 \ --ratio 1:0 --pipeline 8 -d 2000 fio -name=mglru --numjobs=36 --directory=/mnt --size=1408m \ --buffered=1 --ioengine=io_uring --iodepth=128 \ --iodepth_batch_submit=32 --iodepth_batch_complete=32 \ --rw=randread --random_distribution=random --norandommap \ --time_based --ramp_time=10m --runtime=90m --group_reporting & pid=$! sleep 200 memtier_benchmark -S /var/run/memcached/memcached.sock \ -P memcache_binary -n allkeys --key-minimum=1 \ --key-maximum=50000000 --key-pattern=R:R -c 1 -t 36 \ --ratio 0:1 --pipeline 8 --randomize --distinct-client-seed kill -INT $pid wait Client benchmark results: no change (CONFIG_MEMCG=n) Link: https://lkml.kernel.org/r/20220918080010.2920238-10-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Barry Song <baohua@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-27mm: multi-gen LRU: support page table walksYu Zhao1-16/+994
To further exploit spatial locality, the aging prefers to walk page tables to search for young PTEs and promote hot pages. A kill switch will be added in the next patch to disable this behavior. When disabled, the aging relies on the rmap only. NB: this behavior has nothing similar with the page table scanning in the 2.4 kernel [1], which searches page tables for old PTEs, adds cold pages to swapcache and unmaps them. To avoid confusion, the term "iteration" specifically means the traversal of an entire mm_struct list; the term "walk" will be applied to page tables and the rmap, as usual. An mm_struct list is maintained for each memcg, and an mm_struct follows its owner task to the new memcg when this task is migrated. Given an lruvec, the aging iterates lruvec_memcg()->mm_list and calls walk_page_range() with each mm_struct on this list to promote hot pages before it increments max_seq. When multiple page table walkers iterate the same list, each of them gets a unique mm_struct; therefore they can run concurrently. Page table walkers ignore any misplaced pages, e.g., if an mm_struct was migrated, pages it left in the previous memcg will not be promoted when its current memcg is under reclaim. Similarly, page table walkers will not promote pages from nodes other than the one under reclaim. This patch uses the following optimizations when walking page tables: 1. It tracks the usage of mm_struct's between context switches so that page table walkers can skip processes that have been sleeping since the last iteration. 2. It uses generational Bloom filters to record populated branches so that page table walkers can reduce their search space based on the query results, e.g., to skip page tables containing mostly holes or misplaced pages. 3. It takes advantage of the accessed bit in non-leaf PMD entries when CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG=y. 4. It does not zigzag between a PGD table and the same PMD table spanning multiple VMAs. IOW, it finishes all the VMAs within the range of the same PMD table before it returns to a PGD table. This improves the cache performance for workloads that have large numbers of tiny VMAs [2], especially when CONFIG_PGTABLE_LEVELS=5. Server benchmark results: Single workload: fio (buffered I/O): no change Single workload: memcached (anon): +[8, 10]% Ops/sec KB/sec patch1-7: 1147696.57 44640.29 patch1-8: 1245274.91 48435.66 Configurations: no change Client benchmark results: kswapd profiles: patch1-7 48.16% lzo1x_1_do_compress (real work) 8.20% page_vma_mapped_walk (overhead) 7.06% _raw_spin_unlock_irq 2.92% ptep_clear_flush 2.53% __zram_bvec_write 2.11% do_raw_spin_lock 2.02% memmove 1.93% lru_gen_look_around 1.56% free_unref_page_list 1.40% memset patch1-8 49.44% lzo1x_1_do_compress (real work) 6.19% page_vma_mapped_walk (overhead) 5.97% _raw_spin_unlock_irq 3.13% get_pfn_folio 2.85% ptep_clear_flush 2.42% __zram_bvec_write 2.08% do_raw_spin_lock 1.92% memmove 1.44% alloc_zspage 1.36% memset Configurations: no change Thanks to the following developers for their efforts [3]. kernel test robot <lkp@intel.com> [1] https://lwn.net/Articles/23732/ [2] https://llvm.org/docs/ScudoHardenedAllocator.html [3] https://lore.kernel.org/r/202204160827.ekEARWQo-lkp@intel.com/ Link: https://lkml.kernel.org/r/20220918080010.2920238-9-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Barry Song <baohua@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-27mm: multi-gen LRU: exploit locality in rmapYu Zhao1-0/+184
Searching the rmap for PTEs mapping each page on an LRU list (to test and clear the accessed bit) can be expensive because pages from different VMAs (PA space) are not cache friendly to the rmap (VA space). For workloads mostly using mapped pages, searching the rmap can incur the highest CPU cost in the reclaim path. This patch exploits spatial locality to reduce the trips into the rmap. When shrink_page_list() walks the rmap and finds a young PTE, a new function lru_gen_look_around() scans at most BITS_PER_LONG-1 adjacent PTEs. On finding another young PTE, it clears the accessed bit and updates the gen counter of the page mapped by this PTE to (max_seq%MAX_NR_GENS)+1. Server benchmark results: Single workload: fio (buffered I/O): no change Single workload: memcached (anon): +[3, 5]% Ops/sec KB/sec patch1-6: 1106168.46 43025.04 patch1-7: 1147696.57 44640.29 Configurations: no change Client benchmark results: kswapd profiles: patch1-6 39.03% lzo1x_1_do_compress (real work) 18.47% page_vma_mapped_walk (overhead) 6.74% _raw_spin_unlock_irq 3.97% do_raw_spin_lock 2.49% ptep_clear_flush 2.48% anon_vma_interval_tree_iter_first 1.92% folio_referenced_one 1.88% __zram_bvec_write 1.48% memmove 1.31% vma_interval_tree_iter_next patch1-7 48.16% lzo1x_1_do_compress (real work) 8.20% page_vma_mapped_walk (overhead) 7.06% _raw_spin_unlock_irq 2.92% ptep_clear_flush 2.53% __zram_bvec_write 2.11% do_raw_spin_lock 2.02% memmove 1.93% lru_gen_look_around 1.56% free_unref_page_list 1.40% memset Configurations: no change Link: https://lkml.kernel.org/r/20220918080010.2920238-8-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Barry Song <baohua@kernel.org> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-27mm: multi-gen LRU: minimal implementationYu Zhao1-8/+784
To avoid confusion, the terms "promotion" and "demotion" will be applied to the multi-gen LRU, as a new convention; the terms "activation" and "deactivation" will be applied to the active/inactive LRU, as usual. The aging produces young generations. Given an lruvec, it increments max_seq when max_seq-min_seq+1 approaches MIN_NR_GENS. The aging promotes hot pages to the youngest generation when it finds them accessed through page tables; the demotion of cold pages happens consequently when it increments max_seq. Promotion in the aging path does not involve any LRU list operations, only the updates of the gen counter and lrugen->nr_pages[]; demotion, unless as the result of the increment of max_seq, requires LRU list operations, e.g., lru_deactivate_fn(). The aging has the complexity O(nr_hot_pages), since it is only interested in hot pages. The eviction consumes old generations. Given an lruvec, it increments min_seq when lrugen->lists[] indexed by min_seq%MAX_NR_GENS becomes empty. A feedback loop modeled after the PID controller monitors refaults over anon and file types and decides which type to evict when both types are available from the same generation. The protection of pages accessed multiple times through file descriptors takes place in the eviction path. Each generation is divided into multiple tiers. A page accessed N times through file descriptors is in tier order_base_2(N). Tiers do not have dedicated lrugen->lists[], only bits in folio->flags. The aforementioned feedback loop also monitors refaults over all tiers and decides when to protect pages in which tiers (N>1), using the first tier (N=0,1) as a baseline. The first tier contains single-use unmapped clean pages, which are most likely the best choices. In contrast to promotion in the aging path, the protection of a page in the eviction path is achieved by moving this page to the next generation, i.e., min_seq+1, if the feedback loop decides so. This approach has the following advantages: 1. It removes the cost of activation in the buffered access path by inferring whether pages accessed multiple times through file descriptors are statistically hot and thus worth protecting in the eviction path. 2. It takes pages accessed through page tables into account and avoids overprotecting pages accessed multiple times through file descriptors. (Pages accessed through page tables are in the first tier, since N=0.) 3. More tiers provide better protection for pages accessed more than twice through file descriptors, when under heavy buffered I/O workloads. Server benchmark results: Single workload: fio (buffered I/O): +[30, 32]% IOPS BW 5.19-rc1: 2673k 10.2GiB/s patch1-6: 3491k 13.3GiB/s Single workload: memcached (anon): -[4, 6]% Ops/sec KB/sec 5.19-rc1: 1161501.04 45177.25 patch1-6: 1106168.46 43025.04 Configurations: CPU: two Xeon 6154 Mem: total 256G Node 1 was only used as a ram disk to reduce the variance in the results. patch drivers/block/brd.c <<EOF 99,100c99,100 < gfp_flags = GFP_NOIO | __GFP_ZERO | __GFP_HIGHMEM; < page = alloc_page(gfp_flags); --- > gfp_flags = GFP_NOIO | __GFP_ZERO | __GFP_HIGHMEM | __GFP_THISNODE; > page = alloc_pages_node(1, gfp_flags, 0); EOF cat >>/etc/systemd/system.conf <<EOF CPUAffinity=numa NUMAPolicy=bind NUMAMask=0 EOF cat >>/etc/memcached.conf <<EOF -m 184320 -s /var/run/memcached/memcached.sock -a 0766 -t 36 -B binary EOF cat fio.sh modprobe brd rd_nr=1 rd_size=113246208 swapoff -a mkfs.ext4 /dev/ram0 mount -t ext4 /dev/ram0 /mnt mkdir /sys/fs/cgroup/user.slice/test echo 38654705664 >/sys/fs/cgroup/user.slice/test/memory.max echo $$ >/sys/fs/cgroup/user.slice/test/cgroup.procs fio -name=mglru --numjobs=72 --directory=/mnt --size=1408m \ --buffered=1 --ioengine=io_uring --iodepth=128 \ --iodepth_batch_submit=32 --iodepth_batch_complete=32 \ --rw=randread --random_distribution=random --norandommap \ --time_based --ramp_time=10m --runtime=5m --group_reporting cat memcached.sh modprobe brd rd_nr=1 rd_size=113246208 swapoff -a mkswap /dev/ram0 swapon /dev/ram0 memtier_benchmark -S /var/run/memcached/memcached.sock \ -P memcache_binary -n allkeys --key-minimum=1 \ --key-maximum=65000000 --key-pattern=P:P -c 1 -t 36 \ --ratio 1:0 --pipeline 8 -d 2000 memtier_benchmark -S /var/run/memcached/memcached.sock \ -P memcache_binary -n allkeys --key-minimum=1 \ --key-maximum=65000000 --key-pattern=R:R -c 1 -t 36 \ --ratio 0:1 --pipeline 8 --randomize --distinct-client-seed Client benchmark results: kswapd profiles: 5.19-rc1 40.33% page_vma_mapped_walk (overhead) 21.80% lzo1x_1_do_compress (real work) 7.53% do_raw_spin_lock 3.95% _raw_spin_unlock_irq 2.52% vma_interval_tree_iter_next 2.37% folio_referenced_one 2.28% vma_interval_tree_subtree_search 1.97% anon_vma_interval_tree_iter_first 1.60% ptep_clear_flush 1.06% __zram_bvec_write patch1-6 39.03% lzo1x_1_do_compress (real work) 18.47% page_vma_mapped_walk (overhead) 6.74% _raw_spin_unlock_irq 3.97% do_raw_spin_lock 2.49% ptep_clear_flush 2.48% anon_vma_interval_tree_iter_first 1.92% folio_referenced_one 1.88% __zram_bvec_write 1.48% memmove 1.31% vma_interval_tree_iter_next Configurations: CPU: single Snapdragon 7c Mem: total 4G ChromeOS MemoryPressure [1] [1] https://chromium.googlesource.com/chromiumos/platform/tast-tests/ Link: https://lkml.kernel.org/r/20220918080010.2920238-7-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Barry Song <baohua@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-27mm: multi-gen LRU: groundworkYu Zhao1-0/+75
Evictable pages are divided into multiple generations for each lruvec. The youngest generation number is stored in lrugen->max_seq for both anon and file types as they are aged on an equal footing. The oldest generation numbers are stored in lrugen->min_seq[] separately for anon and file types as clean file pages can be evicted regardless of swap constraints. These three variables are monotonically increasing. Generation numbers are truncated into order_base_2(MAX_NR_GENS+1) bits in order to fit into the gen counter in folio->flags. Each truncated generation number is an index to lrugen->lists[]. The sliding window technique is used to track at least MIN_NR_GENS and at most MAX_NR_GENS generations. The gen counter stores a value within [1, MAX_NR_GENS] while a page is on one of lrugen->lists[]. Otherwise it stores 0. There are two conceptually independent procedures: "the aging", which produces young generations, and "the eviction", which consumes old generations. They form a closed-loop system, i.e., "the page reclaim". Both procedures can be invoked from userspace for the purposes of working set estimation and proactive reclaim. These techniques are commonly used to optimize job scheduling (bin packing) in data centers [1][2]. To avoid confusion, the terms "hot" and "cold" will be applied to the multi-gen LRU, as a new convention; the terms "active" and "inactive" will be applied to the active/inactive LRU, as usual. The protection of hot pages and the selection of cold pages are based on page access channels and patterns. There are two access channels: one through page tables and the other through file descriptors. The protection of the former channel is by design stronger because: 1. The uncertainty in determining the access patterns of the former channel is higher due to the approximation of the accessed bit. 2. The cost of evicting the former channel is higher due to the TLB flushes required and the likelihood of encountering the dirty bit. 3. The penalty of underprotecting the former channel is higher because applications usually do not prepare themselves for major page faults like they do for blocked I/O. E.g., GUI applications commonly use dedicated I/O threads to avoid blocking rendering threads. There are also two access patterns: one with temporal locality and the other without. For the reasons listed above, the former channel is assumed to follow the former pattern unless VM_SEQ_READ or VM_RAND_READ is present; the latter channel is assumed to follow the latter pattern unless outlying refaults have been observed [3][4]. The next patch will address the "outlying refaults". Three macros, i.e., LRU_REFS_WIDTH, LRU_REFS_PGOFF and LRU_REFS_MASK, used later are added in this patch to make the entire patchset less diffy. A page is added to the youngest generation on faulting. The aging needs to check the accessed bit at least twice before handing this page over to the eviction. The first check takes care of the accessed bit set on the initial fault; the second check makes sure this page has not been used since then. This protocol, AKA second chance, requires a minimum of two generations, hence MIN_NR_GENS. [1] https://dl.acm.org/doi/10.1145/3297858.3304053 [2] https://dl.acm.org/doi/10.1145/3503222.3507731 [3] https://lwn.net/Articles/495543/ [4] https://lwn.net/Articles/815342/ Link: https://lkml.kernel.org/r/20220918080010.2920238-6-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Barry Song <baohua@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-27mm/vmscan.c: refactor shrink_node()Yu Zhao1-94/+104
This patch refactors shrink_node() to improve readability for the upcoming changes to mm/vmscan.c. Link: https://lkml.kernel.org/r/20220918080010.2920238-4-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Reviewed-by: Barry Song <baohua@kernel.org> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-26Merge branch 'mm-hotfixes-stable' into mm-stableAndrew Morton1-2/+2
2022-09-12mm: fix null-ptr-deref in kswapd_is_running()Kefeng Wang1-11/+16
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.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-12mm/vmscan: make the annotations of refaults code at the right placeYang Yang1-5/+5
After patch "mm/workingset: prepare the workingset detection infrastructure for anon LRU", we can handle the refaults of anonymous pages too. So the annotations of refaults should cover both of anonymous pages and file pages. Link: https://lkml.kernel.org/r/20220813080757.59131-1-yang.yang29@zte.com.cn Fixes: 170b04b7ae4963 ("mm/workingset: prepare the workingset detection infrastructure for anon LRU") Signed-off-by: Yang Yang <yang.yang29@zte.com.cn> Signed-off-by: CGEL ZTE <cgel.zte@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-12mm/vmscan: define macros for refaults in struct lruvecYang Yang1-4/+4
The magic number 0 and 1 are used in several places in vmscan.c. Define macros for them to improve code readability. Link: https://lkml.kernel.org/r/20220808005644.1721066-1-yang.yang29@zte.com.cn Signed-off-by: Yang Yang <yang.yang29@zte.com.cn> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-12vmscan: check folio_test_private(), not folio_get_private()Matthew Wilcox (Oracle)1-2/+2
These two predicates are the same for file pages, but are not the same for anonymous pages. Link: https://lkml.kernel.org/r/20220902192639.1737108-3-willy@infradead.org Fixes: 07f67a8dedc0 ("mm/vmscan: convert shrink_active_list() to use a folio") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reported-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-08-06Merge tag 'mm-stable-2022-08-03' of ↵Linus Torvalds1-135/+197
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: "Most of the MM queue. A few things are still pending. Liam's maple tree rework didn't make it. This has resulted in a few other minor patch series being held over for next time. Multi-gen LRU still isn't merged as we were waiting for mapletree to stabilize. The current plan is to merge MGLRU into -mm soon and to later reintroduce mapletree, with a view to hopefully getting both into 6.1-rc1. Summary: - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe Lin, Yang Shi, Anshuman Khandual and Mike Rapoport - Some kmemleak fixes from Patrick Wang and Waiman Long - DAMON updates from SeongJae Park - memcg debug/visibility work from Roman Gushchin - vmalloc speedup from Uladzislau Rezki - more folio conversion work from Matthew Wilcox - enhancements for coherent device memory mapping from Alex Sierra - addition of shared pages tracking and CoW support for fsdax, from Shiyang Ruan - hugetlb optimizations from Mike Kravetz - Mel Gorman has contributed some pagealloc changes to improve latency and realtime behaviour. - mprotect soft-dirty checking has been improved by Peter Xu - Many other singleton patches all over the place" [ XFS merge from hell as per Darrick Wong in https://lore.kernel.org/all/YshKnxb4VwXycPO8@magnolia/ ] * tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (282 commits) tools/testing/selftests/vm/hmm-tests.c: fix build mm: Kconfig: fix typo mm: memory-failure: convert to pr_fmt() mm: use is_zone_movable_page() helper hugetlbfs: fix inaccurate comment in hugetlbfs_statfs() hugetlbfs: cleanup some comments in inode.c hugetlbfs: remove unneeded header file hugetlbfs: remove unneeded hugetlbfs_ops forward declaration hugetlbfs: use helper macro SZ_1{K,M} mm: cleanup is_highmem() mm/hmm: add a test for cross device private faults selftests: add soft-dirty into run_vmtests.sh selftests: soft-dirty: add test for mprotect mm/mprotect: fix soft-dirty check in can_change_pte_writable() mm: memcontrol: fix potential oom_lock recursion deadlock mm/gup.c: fix formatting in check_and_migrate_movable_page() xfs: fail dax mount if reflink is enabled on a partition mm/memcontrol.c: remove the redundant updating of stats_flush_threshold userfaultfd: don't fail on unrecognized features hugetlb_cgroup: fix wrong hugetlb cgroup numa stat ...
2022-07-30mm: vmpressure: don't count proactive reclaim in vmpressureYosry Ahmed1-10/+17
memory.reclaim is a cgroup v2 interface that allows users to proactively reclaim memory from a memcg, without real memory pressure. Reclaim operations invoke vmpressure, which is used: (a) To notify userspace of reclaim efficiency in cgroup v1, and (b) As a signal for a memcg being under memory pressure for networking (see mem_cgroup_under_socket_pressure()). For (a), vmpressure notifications in v1 are not affected by this change since memory.reclaim is a v2 feature. For (b), the effects of the vmpressure signal (according to Shakeel [1]) are as follows: 1. Reducing send and receive buffers of the current socket. 2. May drop packets on the rx path. 3. May throttle current thread on the tx path. Since proactive reclaim is invoked directly by userspace, not by memory pressure, it makes sense not to throttle networking. Hence, this change makes sure that proactive reclaim caused by memory.reclaim does not trigger vmpressure. [1] https://lore.kernel.org/lkml/CALvZod68WdrXEmBpOkadhB5GPYmCXaDZzXH=yyGOCAjFRn4NDQ@mail.gmail.com/ [yosryahmed@google.com: update documentation] Link: https://lkml.kernel.org/r/20220721173015.2643248-1-yosryahmed@google.com Link: https://lkml.kernel.org/r/20220714064918.2576464-1-yosryahmed@google.com Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Acked-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: NeilBrown <neilb@suse.de> Cc: Alistair Popple <apopple@nvidia.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-30mm: shrinkers: fix double kfree on shrinker nameTetsuo Handa1-2/+7
syzbot is reporting double kfree() at free_prealloced_shrinker() [1], for destroy_unused_super() calls free_prealloced_shrinker() even if prealloc_shrinker() returned an error. Explicitly clear shrinker name when prealloc_shrinker() called kfree(). [roman.gushchin@linux.dev: zero shrinker->name in all cases where shrinker->name is freed] Link: https://lkml.kernel.org/r/YtgteTnQTgyuKUSY@castle Link: https://syzkaller.appspot.com/bug?extid=8b481578352d4637f510 [1] Link: https://lkml.kernel.org/r/ffa62ece-6a42-2644-16cf-0d33ef32c676@I-love.SAKURA.ne.jp Fixes: e33c267ab70de424 ("mm: shrinkers: provide shrinkers with names") Reported-by: syzbot <syzbot+8b481578352d4637f510@syzkaller.appspotmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-04mm, docs: fix comments that mention mem_hotplug_end()Yun-Ze Li1-1/+1
Comments that mention mem_hotplug_end() are confusing as there is no function called mem_hotplug_end(). Fix them by replacing all the occurences of mem_hotplug_end() in the comments with mem_hotplug_done(). [akpm@linux-foundation.org: grammatical fixes] Link: https://lkml.kernel.org/r/20220620071516.1286101-1-p76091292@gs.ncku.edu.tw Signed-off-by: Yun-Ze Li <p76091292@gs.ncku.edu.tw> Cc: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-04mm/swap: convert __delete_from_swap_cache() to a folioMatthew Wilcox (Oracle)1-1/+1
All callers now have a folio, so convert the entire function to operate on folios. Link: https://lkml.kernel.org/r/20220617175020.717127-23-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-04mm: convert page_swap_flags to folio_swap_flagsMatthew Wilcox (Oracle)1-1/+1
The only caller already has a folio, so push the folio->page conversion down a level. Link: https://lkml.kernel.org/r/20220617175020.717127-21-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-04mm: convert destroy_compound_page() to destroy_large_folio()Matthew Wilcox (Oracle)1-2/+2
All callers now have a folio, so push the folio->page conversion down to this function. [akpm@linux-foundation.org: uninline destroy_large_folio() to fix build issue] Link: https://lkml.kernel.org/r/20220617175020.717127-20-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-04mm/vmscan: convert reclaim_pages() to use a folioMatthew Wilcox (Oracle)1-13/+12
Remove a few hidden calls to compound_head, saving 76 bytes of text. Link: https://lkml.kernel.org/r/20220617154248.700416-6-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-04mm/vmscan: convert shrink_active_list() to use a folioMatthew Wilcox (Oracle)1-32/+29
Remove a few hidden calls to compound_head, saving 411 bytes of text. Link: https://lkml.kernel.org/r/20220617154248.700416-5-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-04mm/vmscan: convert move_pages_to_lru() to use a folioMatthew Wilcox (Oracle)1-27/+27
Remove a few hidden calls to compound_head, saving 387 bytes of text on my test configuration. Link: https://lkml.kernel.org/r/20220617154248.700416-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-04mm/vmscan: convert isolate_lru_pages() to use a folioMatthew Wilcox (Oracle)1-33/+33
Remove a few hidden calls to compound_head, saving 279 bytes of text. Link: https://lkml.kernel.org/r/20220617154248.700416-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-04mm/vmscan: convert reclaim_clean_pages_from_list() to foliosMatthew Wilcox (Oracle)1-11/+11
Patch series "nvert much of vmscan to folios" vmscan always operates on folios since it puts the pages on the LRU list. Switching all of these functions from pages to folios saves 1483 bytes of text from removing all the baggage around calling compound_page() and similar functions. This patch (of 5): This is a straightforward conversion which removes several hidden calls to compound_head, saving 330 bytes of kernel text. Link: https://lkml.kernel.org/r/20220617154248.700416-1-willy@infradead.org Link: https://lkml.kernel.org/r/20220617154248.700416-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-04mm: shrinkers: provide shrinkers with namesRoman Gushchin1-3/+55
Currently shrinkers are anonymous objects. For debugging purposes they can be identified by count/scan function names, but it's not always useful: e.g. for superblock's shrinkers it's nice to have at least an idea of to which superblock the shrinker belongs. This commit adds names to shrinkers. register_shrinker() and prealloc_shrinker() functions are extended to take a format and arguments to master a name. In some cases it's not possible to determine a good name at the time when a shrinker is allocated. For such cases shrinker_debugfs_rename() is provided. The expected format is: <subsystem>-<shrinker_type>[:<instance>]-<id> For some shrinkers an instance can be encoded as (MAJOR:MINOR) pair. After this change the shrinker debugfs directory looks like: $ cd /sys/kernel/debug/shrinker/ $ ls dquota-cache-16 sb-devpts-28 sb-proc-47 sb-tmpfs-42 mm-shadow-18 sb-devtmpfs-5 sb-proc-48 sb-tmpfs-43 mm-zspool:zram0-34 sb-hugetlbfs-17 sb-pstore-31 sb-tmpfs-44 rcu-kfree-0 sb-hugetlbfs-33 sb-rootfs-2 sb-tmpfs-49 sb-aio-20 sb-iomem-12 sb-securityfs-6 sb-tracefs-13 sb-anon_inodefs-15 sb-mqueue-21 sb-selinuxfs-22 sb-xfs:vda1-36 sb-bdev-3 sb-nsfs-4 sb-sockfs-8 sb-zsmalloc-19 sb-bpf-32 sb-pipefs-14 sb-sysfs-26 thp-deferred_split-10 sb-btrfs:vda2-24 sb-proc-25 sb-tmpfs-1 thp-zero-9 sb-cgroup2-30 sb-proc-39 sb-tmpfs-27 xfs-buf:vda1-37 sb-configfs-23 sb-proc-41 sb-tmpfs-29 xfs-inodegc:vda1-38 sb-dax-11 sb-proc-45 sb-tmpfs-35 sb-debugfs-7 sb-proc-46 sb-tmpfs-40 [roman.gushchin@linux.dev: fix build warnings] Link: https://lkml.kernel.org/r/Yr+ZTnLb9lJk6fJO@castle Reported-by: kernel test robot <lkp@intel.com> Link: https://lkml.kernel.org/r/20220601032227.4076670-4-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Cc: Dave Chinner <dchinner@redhat.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-04mm: shrinkers: introduce debugfs interface for memory shrinkersRoman Gushchin1-2/+4
This commit introduces the /sys/kernel/debug/shrinker debugfs interface which provides an ability to observe the state of individual kernel memory shrinkers. Because the feature adds some memory overhead (which shouldn't be large unless there is a huge amount of registered shrinkers), it's guarded by a config option (enabled by default). This commit introduces the "count" interface for each shrinker registered in the system. The output is in the following format: <cgroup inode id> <nr of objects on node 0> <nr of objects on node 1>... <cgroup inode id> <nr of objects on node 0> <nr of objects on node 1>... ... To reduce the size of output on machines with many thousands cgroups, if the total number of objects on all nodes is 0, the line is omitted. If the shrinker is not memcg-aware or CONFIG_MEMCG is off, 0 is printed as cgroup inode id. If the shrinker is not numa-aware, 0's are printed for all nodes except the first one. This commit gives debugfs entries simple numeric names, which are not very convenient. The following commit in the series will provide shrinkers with more meaningful names. [akpm@linux-foundation.org: remove WARN_ON_ONCE(), per Roman] Reported-by: syzbot+300d27c79fe6d4cbcc39@syzkaller.appspotmail.com Link: https://lkml.kernel.org/r/20220601032227.4076670-3-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com> Acked-by: Muchun Song <songmuchun@bytedance.com> Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Cc: Dave Chinner <dchinner@redhat.com> Cc: Hillf Danton <hdanton@sina.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-06-29vmscan: Add check_move_unevictable_folios()Matthew Wilcox (Oracle)1-22/+34
Change the guts of check_move_unevictable_pages() over to use folios and add check_move_unevictable_pages() as a wrapper. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-05-26Merge tag 'mm-stable-2022-05-25' of ↵Linus Torvalds1-226/+250
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: "Almost all of MM here. A few things are still getting finished off, reviewed, etc. - Yang Shi has improved the behaviour of khugepaged collapsing of readonly file-backed transparent hugepages. - Johannes Weiner has arranged for zswap memory use to be tracked and managed on a per-cgroup basis. - Munchun Song adds a /proc knob ("hugetlb_optimize_vmemmap") for runtime enablement of the recent huge page vmemmap optimization feature. - Baolin Wang contributes a series to fix some issues around hugetlb pagetable invalidation. - Zhenwei Pi has fixed some interactions between hwpoisoned pages and virtualization. - Tong Tiangen has enabled the use of the presently x86-only page_table_check debugging feature on arm64 and riscv. - David Vernet has done some fixup work on the memcg selftests. - Peter Xu has taught userfaultfd to handle write protection faults against shmem- and hugetlbfs-backed files. - More DAMON development from SeongJae Park - adding online tuning of the feature and support for monitoring of fixed virtual address ranges. Also easier discovery of which monitoring operations are available. - Nadav Amit has done some optimization of TLB flushing during mprotect(). - Neil Brown continues to labor away at improving our swap-over-NFS support. - David Hildenbrand has some fixes to anon page COWing versus get_user_pages(). - Peng Liu fixed some errors in the core hugetlb code. - Joao Martins has reduced the amount of memory consumed by device-dax's compound devmaps. - Some cleanups of the arch-specific pagemap code from Anshuman Khandual. - Muchun Song has found and fixed some errors in the TLB flushing of transparent hugepages. - Roman Gushchin has done more work on the memcg selftests. ... and, of course, many smaller fixes and cleanups. Notably, the customary million cleanup serieses from Miaohe Lin" * tag 'mm-stable-2022-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (381 commits) mm: kfence: use PAGE_ALIGNED helper selftests: vm: add the "settings" file with timeout variable selftests: vm: add "test_hmm.sh" to TEST_FILES selftests: vm: check numa_available() before operating "merge_across_nodes" in ksm_tests selftests: vm: add migration to the .gitignore selftests/vm/pkeys: fix typo in comment ksm: fix typo in comment selftests: vm: add process_mrelease tests Revert "mm/vmscan: never demote for memcg reclaim" mm/kfence: print disabling or re-enabling message include/trace/events/percpu.h: cleanup for "percpu: improve percpu_alloc_percpu event trace" include/trace/events/mmflags.h: cleanup for "tracing: incorrect gfp_t conversion" mm: fix a potential infinite loop in start_isolate_page_range() MAINTAINERS: add Muchun as co-maintainer for HugeTLB zram: fix Kconfig dependency warning mm/shmem: fix shmem folio swapoff hang cgroup: fix an error handling path in alloc_pagecache_max_30M() mm: damon: use HPAGE_PMD_SIZE tracing: incorrect isolate_mote_t cast in mm_vmscan_lru_isolate nodemask.h: fix compilation error with GCC12 ...
2022-05-25Revert "mm/vmscan: never demote for memcg reclaim"Johannes Weiner1-7/+2
This reverts commit 3a235693d3930e1276c8d9cc0ca5807ef292cf0a. Its premise was that cgroup reclaim cares about freeing memory inside the cgroup, and demotion just moves them around within the cgroup limit. Hence, pages from toptier nodes should be reclaimed directly. However, with NUMA balancing now doing tier promotions, demotion is part of the page aging process. Global reclaim demotes the coldest toptier pages to secondary memory, where their life continues and from which they have a chance to get promoted back. Essentially, tiered memory systems have an LRU order that spans multiple nodes. When cgroup reclaims pages coming off the toptier directly, there can be colder pages on lower tier nodes that were demoted by global reclaim. This is an aging inversion, not unlike if cgroups were to reclaim directly from the active lists while there are inactive pages. Proactive reclaim is another factor. The goal of that it is to offload colder pages from expensive RAM to cheaper storage. When lower tier memory is available as an intermediate layer, we want offloading to take advantage of it instead of bypassing to storage. Revert the patch so that cgroups respect the LRU order spanning the memory hierarchy. Of note is a specific undercommit scenario, where all cgroup limits in the system add up to <= available toptier memory. In that case, shuffling pages out to lower tiers first to reclaim them from there is inefficient. This is something could be optimized/short-circuited later on (although care must be taken not to accidentally recreate the aging inversion). Let's ensure correctness first. Link: https://lkml.kernel.org/r/20220518190911.82400-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Shakeel Butt <shakeelb@google.com> Acked-by: Tim Chen <tim.c.chen@linux.intel.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-20mm: don't be stuck to rmap lock on reclaim pathMinchan Kim1-1/+6
The rmap locks(i_mmap_rwsem and anon_vma->root->rwsem) could be contended under memory pressure if processes keep working on their vmas(e.g., fork, mmap, munmap). It makes reclaim path stuck. In our real workload traces, we see kswapd is waiting the lock for 300ms+(worst case, a sec) and it makes other processes entering direct reclaim, which were also stuck on the lock. This patch makes lru aging path try_lock mode like shink_page_list so the reclaim context will keep working with next lru pages without being stuck. if it found the rmap lock contended, it rotates the page back to head of lru in both active/inactive lrus to make them consistent behavior, which is basic starting point rather than adding more heristic. Since this patch introduces a new "contended" field as out-param along with try_lock in-param in rmap_walk_control, it's not immutable any longer if the try_lock is set so remove const keywords on rmap related functions. Since rmap walking is already expensive operation, I doubt the const would help sizable benefit( And we didn't have it until 5.17). In a heavy app workload in Android, trace shows following statistics. It almost removes rmap lock contention from reclaim path. Martin Liu reported: Before: max_dur(ms) min_dur(ms) max-min(dur)ms avg_dur(ms) sum_dur(ms) count blocked_function 1632 0 1631 151.542173 31672 209 page_lock_anon_vma_read 601 0 601 145.544681 28817 198 rmap_walk_file After: max_dur(ms) min_dur(ms) max-min(dur)ms avg_dur(ms) sum_dur(ms) count blocked_function NaN NaN NaN NaN NaN 0.0 NaN 0 0 0 0.127645 1 12 rmap_walk_file [minchan@kernel.org: add comment, per Matthew] Link: https://lkml.kernel.org/r/YnNqeB5tUf6LZ57b@google.com Link: https://lkml.kernel.org/r/20220510215423.164547-1-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: John Dias <joaodias@google.com> Cc: Tim Murray <timmurray@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Martin Liu <liumartin@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13vmscan: remove remaining uses of page in shrink_page_listMatthew Wilcox (Oracle)1-62/+60
These are all straightforward conversions to the folio API. Link: https://lkml.kernel.org/r/20220504182857.4013401-16-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13vmscan: convert the activate_locked portion of shrink_page_list to foliosMatthew Wilcox (Oracle)1-8/+9
This accounts the number of pages activated correctly for large folios. Link: https://lkml.kernel.org/r/20220504182857.4013401-14-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13vmscan: move initialisation of mapping downMatthew Wilcox (Oracle)1-5/+2
Now that we don't interrogate the BDI for congestion, we can delay looking up the folio's mapping until we've got further through the function, reducing register pressure and saving a call to folio_mapping for folios we're adding to the swap cache. Link: https://lkml.kernel.org/r/20220504182857.4013401-13-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13vmscan: convert lazy freeing to foliosMatthew Wilcox (Oracle)1-9/+9
Remove a hidden call to compound_head(), and account nr_pages instead of a single page. This matches the code in lru_lazyfree_fn() that accounts nr_pages to PGLAZYFREE. Link: https://lkml.kernel.org/r/20220504182857.4013401-12-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13vmscan: convert page buffer handling to use foliosMatthew Wilcox (Oracle)1-23/+25
This mostly just removes calls to compound_head() although nr_reclaimed should be incremented by the number of pages, not just 1. Link: https://lkml.kernel.org/r/20220504182857.4013401-11-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13vmscan: convert dirty page handling to foliosMatthew Wilcox (Oracle)1-22/+26
Mostly this just eliminates calls to compound_head(), but NR_VMSCAN_IMMEDIATE was being incremented by 1 instead of by nr_pages. Link: https://lkml.kernel.org/r/20220504182857.4013401-10-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13swap: convert add_to_swap() to take a folioMatthew Wilcox (Oracle)1-3/+3
The only caller already has a folio available, so this saves a conversion. Also convert the return type to boolean. Link: https://lkml.kernel.org/r/20220504182857.4013401-9-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13vmscan: convert the writeback handling in shrink_page_list() to foliosMatthew Wilcox (Oracle)1-36/+42
Slightly more efficient due to fewer calls to compound_head(). Link: https://lkml.kernel.org/r/20220504182857.4013401-7-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13vmscan: use folio_mapped() in shrink_page_list()Matthew Wilcox (Oracle)1-8/+8
Remove some legacy function calls. Link: https://lkml.kernel.org/r/20220504182857.4013401-6-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13mm/vmscan: don't use NUMA_NO_NODE as indicator of page on different nodeWei Yang1-4/+3
Now we are sure there is at least one page on page_list, so it is safe to get the nid of it. This means it is not necessary to use NUMA_NO_NODE as an indicator for the beginning of iteration or a page on different node. Link: https://lkml.kernel.org/r/20220429014426.29223-2-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13mm/vmscan: filter empty page_list at the beginningWei Yang1-4/+6
node_page_list would always be !empty on finishing the loop, except page_list is empty. Let's handle empty page_list before doing any real work including touching PF_MEMALLOC flag. Link: https://lkml.kernel.org/r/20220429014426.29223-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13mm/vmscan: use helper folio_is_file_lru()Miaohe Lin1-2/+2
Use helper folio_is_file_lru() to check whether folio is file lru. Minor readability improvement. [linmiaohe@huawei.com: use folio_is_file_lru()] Link: https://lkml.kernel.org/r/20220428105802.21389-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20220425111232.23182-7-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Huang, Ying <ying.huang@intel.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13mm/vmscan: remove obsolete comment in kswapd_runMiaohe Lin1-1/+0
Since commit 6b700b5b3c59 ("mm/vmscan.c: remove cpu online notification for now"), cpu online notification is removed. So kswapd won't move to proper cpus if cpus are hot-added. Remove this obsolete comment. Link: https://lkml.kernel.org/r/20220425111232.23182-6-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Huang, Ying <ying.huang@intel.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13mm/vmscan: take all base pages of THP into account when race with ↵Miaohe Lin1-1/+1
speculative reference If the page has buffers, shrink_page_list will try to free the buffer mappings associated with the page and try to free the page as well. In the rare race with speculative reference, the page will be freed shortly by speculative reference. But nr_reclaimed is not incremented correctly when we come across the THP. We need to account all the base pages in this case. Link: https://lkml.kernel.org/r/20220425111232.23182-5-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Huang, Ying <ying.huang@intel.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13mm/vmscan: introduce helper function reclaim_page_list()Miaohe Lin1-25/+25
Introduce helper function reclaim_page_list() to eliminate the duplicated code of doing shrink_page_list() and putback_lru_page. Also we can separate node reclaim from node page list operation this way. No functional change intended. Link: https://lkml.kernel.org/r/20220425111232.23182-3-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Huang, Ying <ying.huang@intel.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13mm/vmscan: add a comment about MADV_FREE pages check in ↵Miaohe Lin1-1/+4
folio_check_dirty_writeback Patch series "A few cleanup and fixup patches for vmscan This series contains a few patches to remove obsolete comment, introduce helper to remove duplicated code and so no. Also we take all base pages of THP into account in rare race condition. More details can be found in the respective changelogs. This patch (of 6): The MADV_FREE pages check in folio_check_dirty_writeback is a bit hard to follow. Add a comment to make the code clear. Link: https://lkml.kernel.org/r/20220425111232.23182-2-linmiaohe@huawei.com Suggested-by: Huang, Ying <ying.huang@intel.com> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13mm/vmscan: not necessary to re-init the list for each iterationWei Yang1-3/+1
node_page_list is defined with LIST_HEAD and be cleaned until list_empty. So it is not necessary to re-init it again. [akpm@linux-foundation.org: remove unneeded braces] Link: https://lkml.kernel.org/r/20220426021743.21007-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13mm/vmscan: take min_slab_pages into account when try to call shrink_nodeMiaohe Lin1-1/+2
Since commit 6b4f7799c6a5 ("mm: vmscan: invoke slab shrinkers from shrink_zone()"), slab reclaim and lru page reclaim are done together in the shrink_node. So we should take min_slab_pages into account when try to call shrink_node. Link: https://lkml.kernel.org/r/20220425112118.20924-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-10fs: Remove aops->freepageMatthew Wilcox (Oracle)1-4/+0
All implementations now use free_folio so we can delete the callers and the method. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2022-05-10fs: Add free_folio address space operationMatthew Wilcox (Oracle)1-1/+5
Include documentation and convert the callers to use ->free_folio as well as ->freepage. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2022-05-10fs: Change try_to_free_buffers() to take a folioMatthew Wilcox (Oracle)1-1/+1
All but two of the callers already have a folio; pass a folio into try_to_free_buffers(). This removes the last user of cancel_dirty_page() so remove that wrapper function too. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Jeff Layton <jlayton@kernel.org>
generated by cgit v1.2.3 (git 2.39.0) at 2024-07-13 18:16:16 +0300