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: Yang 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Yang Yang 2022-01-14 14:07:55 -08:00 committed by Linus Torvalds
parent f77a286de4
commit e9ea874a8f
3 changed files with 13 additions and 0 deletions

View File

@ -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

View File

@ -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);

View File

@ -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