| Message ID | 1603968305-8026-6-git-send-email-alex.shi@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | per memcg lru lock | expand |
On Thu, Oct 29, 2020 at 06:44:50PM +0800, Alex Shi wrote: > Simplify lru_add_page_tail(), there are actually only two cases possible: > split_huge_page_to_list(), with list supplied and head isolated from lru > by its caller; or split_huge_page(), with NULL list and head on lru - > because when head is racily isolated from lru, the isolator's reference > will stop the split from getting any further than its page_ref_freeze(). > > So decide between the two cases by "list", but add VM_WARN_ON()s to > verify that they match our lru expectations. > > [Hugh Dickins: rewrite commit log] > Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com> > Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > Acked-by: Hugh Dickins <hughd@google.com> > Cc: Kirill A. Shutemov <kirill@shutemov.name> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Johannes Weiner <hannes@cmpxchg.org> > Cc: Matthew Wilcox <willy@infradead.org> > Cc: Hugh Dickins <hughd@google.com> > Cc: Mika Penttilä <mika.penttila@nextfour.com> > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org Acked-by: Johannes Weiner <hannes@cmpxchg.org>
patch changed since varible rename in 4th patch: From 5014c78418284f70be232a37fa3a4660a54e83c0 Mon Sep 17 00:00:00 2001 From: Alex Shi <alex.shi@linux.alibaba.com> Date: Fri, 10 Jul 2020 12:53:22 +0800 Subject: [PATCH v21 05/20] mm/thp: Simplify lru_add_page_tail() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Simplify lru_add_page_tail(), there are actually only two cases possible: split_huge_page_to_list(), with list supplied and head isolated from lru by its caller; or split_huge_page(), with NULL list and head on lru - because when head is racily isolated from lru, the isolator's reference will stop the split from getting any further than its page_ref_freeze(). So decide between the two cases by "list", but add VM_WARN_ON()s to verify that they match our lru expectations. [Hugh Dickins: rewrite commit log] Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: Mika Penttilä <mika.penttila@nextfour.com> Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/huge_memory.c | 20 ++++++-------------- 1 file changed, 6 insertions(+), 14 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 32a4bf5b80c8..cedcdbeb98b4 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2354,24 +2354,16 @@ static void lru_add_page_tail(struct page *head, struct page *tail, VM_BUG_ON_PAGE(PageLRU(tail), head); lockdep_assert_held(&lruvec_pgdat(lruvec)->lru_lock); - if (!list) - SetPageLRU(tail); - - if (likely(PageLRU(head))) - list_add_tail(&tail->lru, &head->lru); - else if (list) { + if (list) { /* page reclaim is reclaiming a huge page */ + VM_WARN_ON(PageLRU(head)); get_page(tail); list_add_tail(&tail->lru, list); } else { - /* - * Head page has not yet been counted, as an hpage, - * so we must account for each subpage individually. - * - * Put tail on the list at the correct position - * so they all end up in order. - */ - add_page_to_lru_list_tail(tail, lruvec, page_lru(tail)); + /* head is still on lru (and we have it frozen) */ + VM_WARN_ON(!PageLRU(head)); + SetPageLRU(tail); + list_add_tail(&tail->lru, &head->lru); } }
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 93c0b73eb8c6..4b72dd7b8b34 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2354,25 +2354,16 @@ static void lru_add_page_tail(struct page *head, struct page *page_tail, VM_BUG_ON_PAGE(PageLRU(page_tail), head); lockdep_assert_held(&lruvec_pgdat(lruvec)->lru_lock); - if (!list) - SetPageLRU(page_tail); - - if (likely(PageLRU(head))) - list_add_tail(&page_tail->lru, &head->lru); - else if (list) { + if (list) { /* page reclaim is reclaiming a huge page */ + VM_WARN_ON(PageLRU(head)); get_page(page_tail); list_add_tail(&page_tail->lru, list); } else { - /* - * Head page has not yet been counted, as an hpage, - * so we must account for each subpage individually. - * - * Put page_tail on the list at the correct position - * so they all end up in order. - */ - add_page_to_lru_list_tail(page_tail, lruvec, - page_lru(page_tail)); + /* head is still on lru (and we have it frozen) */ + VM_WARN_ON(!PageLRU(head)); + SetPageLRU(page_tail); + list_add_tail(&page_tail->lru, &head->lru); } }