From: Minchan Kim <minchan@xxxxxxxxxx> Subject: mm: make try_to_munlock() return void try_to_munlock returns SWAP_MLOCK if the one of VMAs mapped the page has VM_LOCKED flag. In that time, VM set PG_mlocked to the page if the page is not pte-mapped THP which cannot be mlocked, either. With that, __munlock_isolated_page can use PageMlocked to check whether try_to_munlock is successful or not without relying on try_to_munlock's retval. It helps to make try_to_unmap/try_to_unmap_one simple with upcoming patches. [minchan@xxxxxxxxxx: remove PG_Mlocked VM_BUG_ON check] Link: http://lkml.kernel.org/r/20170411025615.GA6545@bbox Link: http://lkml.kernel.org/r/1489555493-14659-5-git-send-email-minchan@xxxxxxxxxx Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx> Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> Cc: Sasha Levin <alexander.levin@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/rmap.h | 2 +- mm/mlock.c | 6 ++---- mm/rmap.c | 16 ++++------------ 3 files changed, 7 insertions(+), 17 deletions(-) diff -puN include/linux/rmap.h~mm-make-the-try_to_munlock-void-function include/linux/rmap.h --- a/include/linux/rmap.h~mm-make-the-try_to_munlock-void-function +++ a/include/linux/rmap.h @@ -235,7 +235,7 @@ int page_mkclean(struct page *); * called in munlock()/munmap() path to check for other vmas holding * the page mlocked. */ -int try_to_munlock(struct page *); +void try_to_munlock(struct page *); void remove_migration_ptes(struct page *old, struct page *new, bool locked); diff -puN mm/mlock.c~mm-make-the-try_to_munlock-void-function mm/mlock.c --- a/mm/mlock.c~mm-make-the-try_to_munlock-void-function +++ a/mm/mlock.c @@ -123,17 +123,15 @@ static bool __munlock_isolate_lru_page(s */ static void __munlock_isolated_page(struct page *page) { - int ret = SWAP_AGAIN; - /* * Optimization: if the page was mapped just once, that's our mapping * and we don't need to check all the other vmas. */ if (page_mapcount(page) > 1) - ret = try_to_munlock(page); + try_to_munlock(page); /* Did try_to_unlock() succeed or punt? */ - if (ret != SWAP_MLOCK) + if (!PageMlocked(page)) count_vm_event(UNEVICTABLE_PGMUNLOCKED); putback_lru_page(page); diff -puN mm/rmap.c~mm-make-the-try_to_munlock-void-function mm/rmap.c --- a/mm/rmap.c~mm-make-the-try_to_munlock-void-function +++ a/mm/rmap.c @@ -1552,18 +1552,10 @@ static int page_not_mapped(struct page * * Called from munlock code. Checks all of the VMAs mapping the page * to make sure nobody else has this page mlocked. The page will be * returned with PG_mlocked cleared if no other vmas have it mlocked. - * - * Return values are: - * - * SWAP_AGAIN - no vma is holding page mlocked, or, - * SWAP_AGAIN - page mapped in mlocked vma -- couldn't acquire mmap sem - * SWAP_FAIL - page cannot be located at present - * SWAP_MLOCK - page is now mlocked. */ -int try_to_munlock(struct page *page) -{ - int ret; +void try_to_munlock(struct page *page) +{ struct rmap_walk_control rwc = { .rmap_one = try_to_unmap_one, .arg = (void *)TTU_MUNLOCK, @@ -1573,9 +1565,9 @@ int try_to_munlock(struct page *page) }; VM_BUG_ON_PAGE(!PageLocked(page) || PageLRU(page), page); + VM_BUG_ON_PAGE(PageCompound(page) && PageDoubleMap(page), page); - ret = rmap_walk(page, &rwc); - return ret; + rmap_walk(page, &rwc); } void __put_anon_vma(struct anon_vma *anon_vma) _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
