From a1528e21f8915e16252cda1137fe29672c918361 Mon Sep 17 00:00:00 2001 From: Muchun Song Date: Wed, 24 Feb 2021 12:03:35 -0800 Subject: mm: memcontrol: convert NR_SHMEM_PMDMAPPED account to pages Currently we use struct per_cpu_nodestat to cache the vmstat counters, which leads to inaccurate statistics especially THP vmstat counters. In the systems with hundreds of processors it can be GBs of memory. For example, for a 96 CPUs system, the threshold is the maximum number of 125. And the per cpu counters can cache 23.4375 GB in total. The THP page is already a form of batched addition (it will add 512 worth of memory in one go) so skipping the batching seems like sensible. Although every THP stats update overflows the per-cpu counter, resorting to atomic global updates. But it can make the statistics more accuracy for the THP vmstat counters. So we convert the NR_SHMEM_PMDMAPPED account to pages. This patch is consistent with 8f182270dfec ("mm/swap.c: flush lru pvecs on compound page arrival"). Doing this also can make the unit of vmstat counters more unified. Finally, the unit of the vmstat counters are pages, kB and bytes. The B/KB suffix can tell us that the unit is bytes or kB. The rest which is without suffix are pages. Link: https://lkml.kernel.org/r/20201228164110.2838-6-songmuchun@bytedance.com Signed-off-by: Muchun Song Cc: Alexey Dobriyan Cc: Feng Tang Cc: Greg Kroah-Hartman Cc: Hugh Dickins Cc: Johannes Weiner Cc: Joonsoo Kim Cc: Michal Hocko Cc: NeilBrown Cc: Pankaj Gupta Cc: Rafael. J. Wysocki Cc: Randy Dunlap Cc: Roman Gushchin Cc: Sami Tolvanen Cc: Shakeel Butt Cc: Vladimir Davydov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/base/node.c | 3 +-- fs/proc/meminfo.c | 2 +- include/linux/mmzone.h | 3 ++- mm/page_alloc.c | 3 +-- mm/rmap.c | 14 ++++++++++---- 5 files changed, 15 insertions(+), 10 deletions(-) diff --git a/drivers/base/node.c b/drivers/base/node.c index 6d5ac6ffb6e1..7a66aefe4e46 100644 --- a/drivers/base/node.c +++ b/drivers/base/node.c @@ -463,8 +463,7 @@ static ssize_t node_read_meminfo(struct device *dev, , nid, K(node_page_state(pgdat, NR_ANON_THPS)), nid, K(node_page_state(pgdat, NR_SHMEM_THPS)), - nid, K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED) * - HPAGE_PMD_NR), + nid, K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)), nid, K(node_page_state(pgdat, NR_FILE_THPS)), nid, K(node_page_state(pgdat, NR_FILE_PMDMAPPED) * HPAGE_PMD_NR) diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c index cfb107eaa3e6..c61f440570f9 100644 --- a/fs/proc/meminfo.c +++ b/fs/proc/meminfo.c @@ -133,7 +133,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v) show_val_kb(m, "ShmemHugePages: ", global_node_page_state(NR_SHMEM_THPS)); show_val_kb(m, "ShmemPmdMapped: ", - global_node_page_state(NR_SHMEM_PMDMAPPED) * HPAGE_PMD_NR); + global_node_page_state(NR_SHMEM_PMDMAPPED)); show_val_kb(m, "FileHugePages: ", global_node_page_state(NR_FILE_THPS)); show_val_kb(m, "FilePmdMapped: ", diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 788837f40b38..7bdbfeeb5c8c 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -221,7 +221,8 @@ static __always_inline bool vmstat_item_print_in_thp(enum node_stat_item item) return item == NR_ANON_THPS || item == NR_FILE_THPS || - item == NR_SHMEM_THPS; + item == NR_SHMEM_THPS || + item == NR_SHMEM_PMDMAPPED; } /* diff --git a/mm/page_alloc.c b/mm/page_alloc.c index df292d8e659b..069561aadc7b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5585,8 +5585,7 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask) K(node_page_state(pgdat, NR_SHMEM)), #ifdef CONFIG_TRANSPARENT_HUGEPAGE K(node_page_state(pgdat, NR_SHMEM_THPS)), - K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED) - * HPAGE_PMD_NR), + K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)), K(node_page_state(pgdat, NR_ANON_THPS)), #endif K(node_page_state(pgdat, NR_WRITEBACK_TEMP)), diff --git a/mm/rmap.c b/mm/rmap.c index c4d5c63cfd29..1c1b576c0627 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1211,14 +1211,17 @@ void page_add_file_rmap(struct page *page, bool compound) VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page); lock_page_memcg(page); if (compound && PageTransHuge(page)) { - for (i = 0, nr = 0; i < thp_nr_pages(page); i++) { + int nr_pages = thp_nr_pages(page); + + for (i = 0, nr = 0; i < nr_pages; i++) { if (atomic_inc_and_test(&page[i]._mapcount)) nr++; } if (!atomic_inc_and_test(compound_mapcount_ptr(page))) goto out; if (PageSwapBacked(page)) - __inc_node_page_state(page, NR_SHMEM_PMDMAPPED); + __mod_lruvec_page_state(page, NR_SHMEM_PMDMAPPED, + nr_pages); else __inc_node_page_state(page, NR_FILE_PMDMAPPED); } else { @@ -1252,14 +1255,17 @@ static void page_remove_file_rmap(struct page *page, bool compound) /* page still mapped by someone else? */ if (compound && PageTransHuge(page)) { - for (i = 0, nr = 0; i < thp_nr_pages(page); i++) { + int nr_pages = thp_nr_pages(page); + + for (i = 0, nr = 0; i < nr_pages; i++) { if (atomic_add_negative(-1, &page[i]._mapcount)) nr++; } if (!atomic_add_negative(-1, compound_mapcount_ptr(page))) return; if (PageSwapBacked(page)) - __dec_node_page_state(page, NR_SHMEM_PMDMAPPED); + __mod_lruvec_page_state(page, NR_SHMEM_PMDMAPPED, + -nr_pages); else __dec_node_page_state(page, NR_FILE_PMDMAPPED); } else { -- cgit v1.2.3