Messages in this thread Patch in this message | | | From | KOSAKI Motohiro <> | Subject | [PATCH] Replace page_mapping_inuse() with page_mapped() | Date | Wed, 2 Dec 2009 12:28:26 +0900 (JST) |
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> On 12/01/2009 09:55 PM, KOSAKI Motohiro wrote: > >> btw, current shrink_active_list() have unnecessary page_mapping_inuse() call. > >> it prevent to drop page reference bit from unmapped cache page. it mean > >> we protect unmapped cache page than mapped page. it is strange. > >> > > How about this? > > > > --------------------------------- > > SplitLRU VM replacement algorithm assume shrink_active_list() clear > > the page's reference bit. but unnecessary page_mapping_inuse() test > > prevent it. > > > > This patch remove it. > > > Shrink_page_list ignores the referenced bit on pages > that are !page_mapping_inuse(). > > if (sc->order <= PAGE_ALLOC_COSTLY_ORDER && > referenced && > page_mapping_inuse(page) > && !(vm_flags & VM_LOCKED)) > goto activate_locked; > > The reason we leave the referenced bit on unmapped > pages is that we want the next reference to a deactivated > page cache page to move that page back to the active > list. We do not want to require that such a page gets > accessed twice before being reactivated while on the > inactive list, because (1) we know it was a frequently > accessed page already and (2) ongoing streaming IO > might evict it from the inactive list before it gets accessed > twice. > > Arguably, we should just replace the page_mapping_inuse() > in both places with page_mapped() to simplify things.
Ah, yes. /me was slept. thanks correct me.
From 61340720e6e66b645db8d5410e89fd3b67eda907 Mon Sep 17 00:00:00 2001 From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Date: Wed, 2 Dec 2009 12:05:26 +0900 Subject: [PATCH] Replace page_mapping_inuse() with page_mapped()
page reclaim logic need to distingish mapped and unmapped pages. However page_mapping_inuse() don't provide proper test way. it test the address space (i.e. file) is mmpad(). Why `page' reclaim need care unrelated page's mapped state? it's unrelated.
Thus, This patch replace page_mapping_inuse() with page_mapped()
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> --- mm/vmscan.c | 25 ++----------------------- 1 files changed, 2 insertions(+), 23 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c index 00156f2..350b9cc 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -277,27 +277,6 @@ unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask, return ret; } -/* Called without lock on whether page is mapped, so answer is unstable */ -static inline int page_mapping_inuse(struct page *page) -{ - struct address_space *mapping; - - /* Page is in somebody's page tables. */ - if (page_mapped(page)) - return 1; - - /* Be more reluctant to reclaim swapcache than pagecache */ - if (PageSwapCache(page)) - return 1; - - mapping = page_mapping(page); - if (!mapping) - return 0; - - /* File is mmap'd by somebody? */ - return mapping_mapped(mapping); -} - static inline int is_page_cache_freeable(struct page *page) { /* @@ -663,7 +642,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, * try_to_unmap moves it to unevictable list */ if (sc->order <= PAGE_ALLOC_COSTLY_ORDER && - referenced && page_mapping_inuse(page) + referenced && page_mapped(page) && !(vm_flags & VM_LOCKED)) goto activate_locked; @@ -1347,7 +1326,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, } /* page_referenced clears PageReferenced */ - if (page_mapping_inuse(page) && + if (page_mapped(page) && page_referenced(page, 0, sc->mem_cgroup, &vm_flags)) { nr_rotated++; /* -- 1.6.5.2
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