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mm, page_alloc: use check_pages_enabled static key to check tail pages 

Commit 700d2e9a36 ("mm, page_alloc: reduce page alloc/free sanity
checks") has introduced a new static key check_pages_enabled to control
when struct pages are sanity checked during allocation and freeing.  Mel
Gorman suggested that free_tail_pages_check() could use this static key as
well, instead of relying on CONFIG_DEBUG_VM.  That makes sense, so do
that.  Also rename the function to free_tail_page_prepare() because it
works on a single tail page and has a struct page preparation component as
well as the optional checking component.

Also remove some unnecessary unlikely() within static_branch_unlikely()
statements that Mel pointed out for commit 700d2e9a36.

Link: https://lkml.kernel.org/r/20230405142840.11068-1-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Suggested-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Alexander Halbuer <halbuer@sra.uni-hannover.de>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Vlastimil Babka 2023-04-05 16:28:40 +02:00 committed by Andrew Morton
parent 27da93d8e6
commit 8666925c49
2 changed files with 6 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
mm/hugetlb_vmemmap.c
View File

@ -264,7 +264,7 @@ static void vmemmap_remap_pte(pte_t *pte, unsigned long addr,
* How many struct page structs need to be reset. When we reuse the head
* struct page, the special metadata (e.g. page->flags or page->mapping)
* cannot copy to the tail struct page structs. The invalid value will be
* checked in the free_tail_pages_check(). In order to avoid the message
* checked in the free_tail_page_prepare(). In order to avoid the message
* of "corrupted mapping in tail page". We need to reset at least 3 (one
* head struct page struct and two tail struct page structs) struct page
* structs.

10
mm/page_alloc.c
View File

@ -1131,7 +1131,7 @@ static inline bool free_page_is_bad(struct page *page)
return true;
}
static int free_tail_pages_check(struct page *head_page, struct page *page)
static int free_tail_page_prepare(struct page *head_page, struct page *page)
{
struct folio *folio = (struct folio *)head_page;
int ret = 1;
@ -1142,7 +1142,7 @@ static int free_tail_pages_check(struct page *head_page, struct page *page)
*/
BUILD_BUG_ON((unsigned long)LIST_POISON1 & 1);
if (!IS_ENABLED(CONFIG_DEBUG_VM)) {
if (!static_branch_unlikely(&check_pages_enabled)) {
ret = 0;
goto out;
}
@ -1276,9 +1276,9 @@ static __always_inline bool free_pages_prepare(struct page *page,
ClearPageHasHWPoisoned(page);
for (i = 1; i < (1 << order); i++) {
if (compound)
bad += free_tail_pages_check(page, page + i);
bad += free_tail_page_prepare(page, page + i);
if (is_check_pages_enabled()) {
if (unlikely(free_page_is_bad(page + i))) {
if (free_page_is_bad(page + i)) {
bad++;
continue;
}
@ -1627,7 +1627,7 @@ static inline bool check_new_pages(struct page *page, unsigned int order)
for (int i = 0; i < (1 << order); i++) {
struct page *p = page + i;
if (unlikely(check_new_page(p)))
if (check_new_page(p))
return true;
}
}