mm: rmap: split out page_remove_file_rmap()
page_remove_rmap() has too many branches on PageAnon() and is hard to follow. Move the file part into a separate function. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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78
mm/rmap.c
78
mm/rmap.c
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@ -1054,6 +1054,36 @@ void page_add_file_rmap(struct page *page)
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mem_cgroup_end_page_stat(memcg, locked, flags);
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}
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static void page_remove_file_rmap(struct page *page)
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{
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struct mem_cgroup *memcg;
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unsigned long flags;
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bool locked;
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memcg = mem_cgroup_begin_page_stat(page, &locked, &flags);
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/* page still mapped by someone else? */
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if (!atomic_add_negative(-1, &page->_mapcount))
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goto out;
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/* Hugepages are not counted in NR_FILE_MAPPED for now. */
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if (unlikely(PageHuge(page)))
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goto out;
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/*
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* We use the irq-unsafe __{inc|mod}_zone_page_stat because
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* these counters are not modified in interrupt context, and
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* pte lock(a spinlock) is held, which implies preemption disabled.
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*/
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__dec_zone_page_state(page, NR_FILE_MAPPED);
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mem_cgroup_dec_page_stat(memcg, MEM_CGROUP_STAT_FILE_MAPPED);
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if (unlikely(PageMlocked(page)))
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clear_page_mlock(page);
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out:
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mem_cgroup_end_page_stat(memcg, locked, flags);
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}
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/**
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* page_remove_rmap - take down pte mapping from a page
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* @page: page to remove mapping from
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@ -1062,46 +1092,33 @@ void page_add_file_rmap(struct page *page)
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*/
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void page_remove_rmap(struct page *page)
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{
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struct mem_cgroup *uninitialized_var(memcg);
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bool anon = PageAnon(page);
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unsigned long flags;
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bool locked;
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/*
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* The anon case has no mem_cgroup page_stat to update; but may
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* uncharge_page() below, where the lock ordering can deadlock if
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* we hold the lock against page_stat move: so avoid it on anon.
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*/
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if (!anon)
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memcg = mem_cgroup_begin_page_stat(page, &locked, &flags);
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if (!PageAnon(page)) {
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page_remove_file_rmap(page);
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return;
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}
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/* page still mapped by someone else? */
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if (!atomic_add_negative(-1, &page->_mapcount))
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goto out;
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return;
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/* Hugepages are not counted in NR_ANON_PAGES for now. */
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if (unlikely(PageHuge(page)))
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return;
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/*
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* Hugepages are not counted in NR_ANON_PAGES nor NR_FILE_MAPPED
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* and not charged by memcg for now.
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*
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* We use the irq-unsafe __{inc|mod}_zone_page_stat because
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* these counters are not modified in interrupt context, and
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* these counters are not modified in interrupt context, and
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* pte lock(a spinlock) is held, which implies preemption disabled.
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*/
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if (unlikely(PageHuge(page)))
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goto out;
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if (anon) {
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if (PageTransHuge(page))
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__dec_zone_page_state(page,
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NR_ANON_TRANSPARENT_HUGEPAGES);
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__mod_zone_page_state(page_zone(page), NR_ANON_PAGES,
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-hpage_nr_pages(page));
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} else {
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__dec_zone_page_state(page, NR_FILE_MAPPED);
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mem_cgroup_dec_page_stat(memcg, MEM_CGROUP_STAT_FILE_MAPPED);
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}
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if (PageTransHuge(page))
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__dec_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES);
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__mod_zone_page_state(page_zone(page), NR_ANON_PAGES,
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-hpage_nr_pages(page));
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if (unlikely(PageMlocked(page)))
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clear_page_mlock(page);
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/*
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* It would be tidy to reset the PageAnon mapping here,
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* but that might overwrite a racing page_add_anon_rmap
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@ -1111,9 +1128,6 @@ void page_remove_rmap(struct page *page)
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* Leaving it set also helps swapoff to reinstate ptes
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* faster for those pages still in swapcache.
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*/
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out:
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if (!anon)
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mem_cgroup_end_page_stat(memcg, locked, flags);
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}
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/*
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