mm: memcontrol: convert NR_FILE_THPS 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 if 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_FILE_THPS 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/20201228164110.2838-4-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>
Cc: Rafael. J. Wysocki <rafael@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/base/node.c b/drivers/base/node.c
index 6da0c3508bc9cef6a5060cf297096be66926dbb8..d5952f7549115534359fad78e38a04347a106284 100644 (file)
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -466,8 +466,7 @@ static ssize_t node_read_meminfo(struct device *dev,
                                    HPAGE_PMD_NR),
                             nid, K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED) *
                                    HPAGE_PMD_NR),
-                            nid, K(node_page_state(pgdat, NR_FILE_THPS) *
-                                   HPAGE_PMD_NR),
+                            nid, K(node_page_state(pgdat, NR_FILE_THPS)),
                             nid, K(node_page_state(pgdat, NR_FILE_PMDMAPPED) *
                                    HPAGE_PMD_NR)
 #endif

diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
index a635c8a84ddf50254eb046e03d6953838fddee06..7ea4679880c8dfdf197fe621ce056befedc8a2a1 100644 (file)
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -135,7 +135,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
        show_val_kb(m, "ShmemPmdMapped: ",
                    global_node_page_state(NR_SHMEM_PMDMAPPED) * HPAGE_PMD_NR);
        show_val_kb(m, "FileHugePages:  ",
-                   global_node_page_state(NR_FILE_THPS) * HPAGE_PMD_NR);
+                   global_node_page_state(NR_FILE_THPS));
        show_val_kb(m, "FilePmdMapped:  ",
                    global_node_page_state(NR_FILE_PMDMAPPED) * HPAGE_PMD_NR);
 #endif

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 67d50ef5dd2050baf9da4f4de92ca7bf0b4358fe..b751a9898bb6895989b523d152b0350f3f0728e5 100644 (file)
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -219,7 +219,8 @@ static __always_inline bool vmstat_item_print_in_thp(enum node_stat_item item)
        if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
                return false;
 
-       return item == NR_ANON_THPS;
+       return item == NR_ANON_THPS ||
+              item == NR_FILE_THPS;
 }
 
 /*

diff --git a/mm/filemap.c b/mm/filemap.c
index 820d81901eae98b29d17e9565c9b4d8f5199f2ad..9efe059e2b58e002df32595d9d3b81095bea18b4 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -208,7 +208,7 @@ static void unaccount_page_cache_page(struct address_space *mapping,
                if (PageTransHuge(page))
                        __dec_lruvec_page_state(page, NR_SHMEM_THPS);
        } else if (PageTransHuge(page)) {
-               __dec_lruvec_page_state(page, NR_FILE_THPS);
+               __mod_lruvec_page_state(page, NR_FILE_THPS, -nr);
                filemap_nr_thps_dec(mapping);
        }
 

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 3691e863070a5aef3f6b1763b6c0e590bf1d344f..77181faa2340812900e991f62a0ca95a4a90cd14 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2752,10 +2752,13 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
                }
                spin_unlock(&ds_queue->split_queue_lock);
                if (mapping) {
+                       int nr = thp_nr_pages(head);
+
                        if (PageSwapBacked(head))
                                __dec_lruvec_page_state(head, NR_SHMEM_THPS);
                        else
-                               __dec_lruvec_page_state(head, NR_FILE_THPS);
+                               __mod_lruvec_page_state(head, NR_FILE_THPS,
+                                                       -nr);
                }
 
                __split_huge_page(page, list, end);

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index fb0fdaec34d5773be448157d5b0c6aa999ae19b7..c427fe2ca7ffece09fc765cbe1d6e1c97b8a8076 100644 (file)
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1643,6 +1643,7 @@ static void collapse_file(struct mm_struct *mm,
        XA_STATE_ORDER(xas, &mapping->i_pages, start, HPAGE_PMD_ORDER);
        int nr_none = 0, result = SCAN_SUCCEED;
        bool is_shmem = shmem_file(file);
+       int nr;
 
        VM_BUG_ON(!IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && !is_shmem);
        VM_BUG_ON(start & (HPAGE_PMD_NR - 1));
@@ -1854,11 +1855,12 @@ out_unlock:
                put_page(page);
                goto xa_unlocked;
        }
+       nr = thp_nr_pages(new_page);
 
        if (is_shmem)
                __inc_lruvec_page_state(new_page, NR_SHMEM_THPS);
        else {
-               __inc_lruvec_page_state(new_page, NR_FILE_THPS);
+               __mod_lruvec_page_state(new_page, NR_FILE_THPS, nr);
                filemap_nr_thps_inc(mapping);
        }
 

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index b2405f049006a4a8157170116ba7a7d41496775b..fc552f57d3fbc64b60af0cb8bb6496f7342b7c0a 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1534,7 +1534,7 @@ static struct memory_stat memory_stats[] = {
         * constant(e.g. powerpc).
         */
        { "anon_thp", PAGE_SIZE, NR_ANON_THPS },
-       { "file_thp", 0, NR_FILE_THPS },
+       { "file_thp", PAGE_SIZE, NR_FILE_THPS },
        { "shmem_thp", 0, NR_SHMEM_THPS },
 #endif
        { "inactive_anon", PAGE_SIZE, NR_INACTIVE_ANON },
@@ -1566,8 +1566,7 @@ static int __init memory_stats_init(void)
 
        for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-               if (memory_stats[i].idx == NR_FILE_THPS ||
-                   memory_stats[i].idx == NR_SHMEM_THPS)
+               if (memory_stats[i].idx == NR_SHMEM_THPS)
                        memory_stats[i].ratio = HPAGE_PMD_SIZE;
 #endif
                VM_BUG_ON(!memory_stats[i].ratio);