Commit e9ea874a authored by Yang Yang's avatar Yang Yang Committed by Linus Torvalds
Browse files

mm/vmstat: add events for THP max_ptes_* exceeds 

There are interfaces to adjust max_ptes_none, max_ptes_swap,
max_ptes_shared values, see
  /sys/kernel/mm/transparent_hugepage/khugepaged/.

But system administrator may not know which value is the best.  So Add
those events to support adjusting max_ptes_* to suitable values.

For example, if default max_ptes_swap value causes too much failures,
and system uses zram whose IO is fast, administrator could increase
max_ptes_swap until THP_SCAN_EXCEED_SWAP_PTE not increase anymore.

Link: https://lkml.kernel.org/r/20211225094036.574157-1-yang.yang29@zte.com.cn


Signed-off-by: default avatarYang Yang <yang.yang29@zte.com.cn>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Saravanan D <saravanand@fb.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f77a286d

include/linux/vm_event_item.h

+3 −0
Original line number Diff line number Diff line
@@ -98,6 +98,9 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, 
		THP_SPLIT_PAGE_FAILED,

		THP_DEFERRED_SPLIT_PAGE,

		THP_SPLIT_PMD,

		THP_SCAN_EXCEED_NONE_PTE,

		THP_SCAN_EXCEED_SWAP_PTE,

		THP_SCAN_EXCEED_SHARED_PTE,

#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD

		THP_SPLIT_PUD,

#endif

mm/khugepaged.c

+7 −0
Original line number Diff line number Diff line
@@ -618,6 +618,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, 
				continue;

			} else {

				result = SCAN_EXCEED_NONE_PTE;

				count_vm_event(THP_SCAN_EXCEED_NONE_PTE);

				goto out;

			}

		}
@@ -636,6 +637,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, 
		if (page_mapcount(page) > 1 &&

				++shared > khugepaged_max_ptes_shared) {

			result = SCAN_EXCEED_SHARED_PTE;

			count_vm_event(THP_SCAN_EXCEED_SHARED_PTE);

			goto out;

		}
@@ -1253,6 +1255,7 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, 
				continue;

			} else {

				result = SCAN_EXCEED_SWAP_PTE;

				count_vm_event(THP_SCAN_EXCEED_SWAP_PTE);

				goto out_unmap;

			}

		}
@@ -1262,6 +1265,7 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, 
				continue;

			} else {

				result = SCAN_EXCEED_NONE_PTE;

				count_vm_event(THP_SCAN_EXCEED_NONE_PTE);

				goto out_unmap;

			}

		}
@@ -1290,6 +1294,7 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, 
		if (page_mapcount(page) > 1 &&

				++shared > khugepaged_max_ptes_shared) {

			result = SCAN_EXCEED_SHARED_PTE;

			count_vm_event(THP_SCAN_EXCEED_SHARED_PTE);

			goto out_unmap;

		}
@@ -2000,6 +2005,7 @@ static void khugepaged_scan_file(struct mm_struct *mm, 
		if (xa_is_value(page)) {

			if (++swap > khugepaged_max_ptes_swap) {

				result = SCAN_EXCEED_SWAP_PTE;

				count_vm_event(THP_SCAN_EXCEED_SWAP_PTE);

				break;

			}

			continue;
@@ -2046,6 +2052,7 @@ static void khugepaged_scan_file(struct mm_struct *mm, 
	if (result == SCAN_SUCCEED) {

		if (present < HPAGE_PMD_NR - khugepaged_max_ptes_none) {

			result = SCAN_EXCEED_NONE_PTE;

			count_vm_event(THP_SCAN_EXCEED_NONE_PTE);

		} else {

			node = khugepaged_find_target_node();

			collapse_file(mm, file, start, hpage, node);

mm/vmstat.c

+3 −0
Original line number Diff line number Diff line
@@ -1353,6 +1353,9 @@ const char * const vmstat_text[] = { 
	"thp_split_page_failed",

	"thp_deferred_split_page",

	"thp_split_pmd",

	"thp_scan_exceed_none_pte",

	"thp_scan_exceed_swap_pte",

	"thp_scan_exceed_share_pte",

#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD

	"thp_split_pud",

#endif