mm: add __clear_page_lru_flags() to replace page_off_lru()

Similar to page_off_lru(), the new function does non-atomic clearing
of PageLRU() in addition to PageActive() and PageUnevictable(), on a
page that has no references left.

If PageActive() and PageUnevictable() are both set, refuse to clear
either and leave them to bad_page(). This is a behavior change that
is meant to help debug.

Link: https://lore.kernel.org/linux-mm/20201207220949.830352-7-yuzhao@google.com/
Link: https://lkml.kernel.org/r/20210122220600.906146-7-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Yu Zhao 2021-02-24 12:08:28 -08:00 committed by Linus Torvalds
parent 46ae6b2cc2
commit 8756017962
3 changed files with 13 additions and 24 deletions

View File

@ -61,27 +61,19 @@ static inline enum lru_list page_lru_base_type(struct page *page)
}
/**
* page_off_lru - which LRU list was page on? clearing its lru flags.
* @page: the page to test
*
* Returns the LRU list a page was on, as an index into the array of LRU
* lists; and clears its Unevictable or Active flags, ready for freeing.
* __clear_page_lru_flags - clear page lru flags before releasing a page
* @page: the page that was on lru and now has a zero reference
*/
static __always_inline enum lru_list page_off_lru(struct page *page)
static __always_inline void __clear_page_lru_flags(struct page *page)
{
enum lru_list lru;
__ClearPageLRU(page);
if (PageUnevictable(page)) {
__ClearPageUnevictable(page);
lru = LRU_UNEVICTABLE;
} else {
lru = page_lru_base_type(page);
if (PageActive(page)) {
__ClearPageActive(page);
lru += LRU_ACTIVE;
}
}
return lru;
/* this shouldn't happen, so leave the flags to bad_page() */
if (PageActive(page) && PageUnevictable(page))
return;
__ClearPageActive(page);
__ClearPageUnevictable(page);
}
/**

View File

@ -84,9 +84,8 @@ static void __page_cache_release(struct page *page)
lruvec = lock_page_lruvec_irqsave(page, &flags);
VM_BUG_ON_PAGE(!PageLRU(page), page);
__ClearPageLRU(page);
del_page_from_lru_list(page, lruvec);
page_off_lru(page);
__clear_page_lru_flags(page);
unlock_page_lruvec_irqrestore(lruvec, flags);
}
__ClearPageWaiters(page);
@ -911,9 +910,8 @@ void release_pages(struct page **pages, int nr)
lock_batch = 0;
VM_BUG_ON_PAGE(!PageLRU(page), page);
__ClearPageLRU(page);
del_page_from_lru_list(page, lruvec);
page_off_lru(page);
__clear_page_lru_flags(page);
}
__ClearPageWaiters(page);

View File

@ -1849,8 +1849,7 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
SetPageLRU(page);
if (unlikely(put_page_testzero(page))) {
__ClearPageLRU(page);
__ClearPageActive(page);
__clear_page_lru_flags(page);
if (unlikely(PageCompound(page))) {
spin_unlock_irq(&lruvec->lru_lock);