Messages in this thread Patch in this message | | | From | Alex Shi <> | Subject | [PATCH v13 01/18] mm/vmscan: remove unnecessary lruvec adding | Date | Fri, 19 Jun 2020 16:33:39 +0800 |
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We don't have to add a freeable page into lru and then remove from it. This change saves a couple of actions and makes the moving more clear.
The SetPageLRU needs to be kept here for list intergrity. Otherwise: #0 mave_pages_to_lru #1 release_pages if (put_page_testzero()) if !put_page_testzero !PageLRU //skip lru_lock list_add(&page->lru,) list_add(&page->lru,) //corrupt
[akpm@linux-foundation.org: coding style fixes] Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tejun Heo <tj@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/vmscan.c | 32 +++++++++++++++++++++----------- 1 file changed, 21 insertions(+), 11 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c index b6d84326bdf2..81228334f7d6 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1855,26 +1855,29 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec, while (!list_empty(list)) { page = lru_to_page(list); VM_BUG_ON_PAGE(PageLRU(page), page); + list_del(&page->lru); if (unlikely(!page_evictable(page))) { - list_del(&page->lru); spin_unlock_irq(&pgdat->lru_lock); putback_lru_page(page); spin_lock_irq(&pgdat->lru_lock); continue; } - lruvec = mem_cgroup_page_lruvec(page, pgdat); + /* + * The SetPageLRU needs to be kept here for list intergrity. + * Otherwise: + * #0 mave_pages_to_lru #1 release_pages + * if (put_page_testzero()) + * if !put_page_testzero + * !PageLRU //skip lru_lock + * list_add(&page->lru,) + * list_add(&page->lru,) //corrupt + */ SetPageLRU(page); - lru = page_lru(page); - - nr_pages = hpage_nr_pages(page); - update_lru_size(lruvec, lru, page_zonenum(page), nr_pages); - list_move(&page->lru, &lruvec->lists[lru]); - if (put_page_testzero(page)) { + if (unlikely(put_page_testzero(page))) { __ClearPageLRU(page); __ClearPageActive(page); - del_page_from_lru_list(page, lruvec, lru); if (unlikely(PageCompound(page))) { spin_unlock_irq(&pgdat->lru_lock); @@ -1882,9 +1885,16 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec, spin_lock_irq(&pgdat->lru_lock); } else list_add(&page->lru, &pages_to_free); - } else { - nr_moved += nr_pages; + continue; } + + lruvec = mem_cgroup_page_lruvec(page, pgdat); + lru = page_lru(page); + nr_pages = hpage_nr_pages(page); + + update_lru_size(lruvec, lru, page_zonenum(page), nr_pages); + list_add(&page->lru, &lruvec->lists[lru]); + nr_moved += nr_pages; } /* -- 1.8.3.1
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