From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754046AbdBNTgc (ORCPT ); Tue, 14 Feb 2017 14:36:32 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:33732 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752318AbdBNTgR (ORCPT ); Tue, 14 Feb 2017 14:36:17 -0500 Smtp-Origin-Hostprefix: devbig From: Shaohua Li Smtp-Origin-Hostname: devbig638.prn2.facebook.com To: , CC: , , , , , , , Smtp-Origin-Cluster: prn2c22 Subject: [PATCH V3 3/7] mm: reclaim MADV_FREE pages Date: Tue, 14 Feb 2017 11:36:09 -0800 Message-ID: X-Mailer: git-send-email 2.9.3 In-Reply-To: References: X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-02-14_12:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When memory pressure is high, we free MADV_FREE pages. If the pages are not dirty in pte, the pages could be freed immediately. Otherwise we can't reclaim them. We put the pages back to anonumous LRU list (by setting SwapBacked flag) and the pages will be reclaimed in normal swapout way. We use normal page reclaim policy. Since MADV_FREE pages are put into inactive file list, such pages and inactive file pages are reclaimed according to their age. This is expected, because we don't want to reclaim too many MADV_FREE pages before used once pages. Based on Minchan's original patch Cc: Michal Hocko Cc: Minchan Kim Cc: Hugh Dickins Cc: Johannes Weiner Cc: Rik van Riel Cc: Mel Gorman Cc: Andrew Morton Signed-off-by: Shaohua Li --- mm/huge_memory.c | 2 ++ mm/madvise.c | 1 + mm/rmap.c | 17 ++++++++++++----- mm/vmscan.c | 30 +++++++++++++++++++++--------- 4 files changed, 36 insertions(+), 14 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 4ddda58..3bb5ad5 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1571,6 +1571,8 @@ bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, set_pmd_at(mm, addr, pmd, orig_pmd); tlb_remove_pmd_tlb_entry(tlb, pmd, addr); } + + mark_page_lazyfree(page); ret = true; out: spin_unlock(ptl); diff --git a/mm/madvise.c b/mm/madvise.c index 639c476..2faed38 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -412,6 +412,7 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr, set_pte_at(mm, addr, pte, ptent); tlb_remove_tlb_entry(tlb, pte, addr); } + mark_page_lazyfree(page); } out: if (nr_swap) { diff --git a/mm/rmap.c b/mm/rmap.c index af50eae..2cbdada 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1419,11 +1419,18 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, VM_BUG_ON_PAGE(!PageSwapCache(page) && PageSwapBacked(page), page); - if (!PageDirty(page) && (flags & TTU_LZFREE)) { - /* It's a freeable page by MADV_FREE */ - dec_mm_counter(mm, MM_ANONPAGES); - rp->lazyfreed++; - goto discard; + if (flags & TTU_LZFREE) { + if (!PageDirty(page)) { + /* It's a freeable page by MADV_FREE */ + dec_mm_counter(mm, MM_ANONPAGES); + rp->lazyfreed++; + goto discard; + } else { + set_pte_at(mm, address, pvmw.pte, pteval); + ret = SWAP_FAIL; + page_vma_mapped_walk_done(&pvmw); + break; + } } if (swap_duplicate(entry) < 0) { diff --git a/mm/vmscan.c b/mm/vmscan.c index 26c3b40..435149c 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -911,7 +911,7 @@ static void page_check_dirty_writeback(struct page *page, * Anonymous pages are not handled by flushers and must be written * from reclaim context. Do not stall reclaim based on them */ - if (!page_is_file_cache(page)) { + if (!page_is_file_cache(page) || page_is_lazyfree(page)) { *dirty = false; *writeback = false; return; @@ -971,7 +971,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, int may_enter_fs; enum page_references references = PAGEREF_RECLAIM_CLEAN; bool dirty, writeback; - bool lazyfree = false; + bool lazyfree; int ret = SWAP_SUCCESS; cond_resched(); @@ -986,6 +986,8 @@ static unsigned long shrink_page_list(struct list_head *page_list, sc->nr_scanned++; + lazyfree = page_is_lazyfree(page); + if (unlikely(!page_evictable(page))) goto cull_mlocked; @@ -993,7 +995,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, goto keep_locked; /* Double the slab pressure for mapped and swapcache pages */ - if (page_mapped(page) || PageSwapCache(page)) + if ((page_mapped(page) || PageSwapCache(page)) && !lazyfree) sc->nr_scanned++; may_enter_fs = (sc->gfp_mask & __GFP_FS) || @@ -1119,13 +1121,13 @@ static unsigned long shrink_page_list(struct list_head *page_list, /* * Anonymous process memory has backing store? * Try to allocate it some swap space here. + * Lazyfree page could be freed directly */ - if (PageAnon(page) && !PageSwapCache(page)) { + if (PageAnon(page) && !PageSwapCache(page) && !lazyfree) { if (!(sc->gfp_mask & __GFP_IO)) goto keep_locked; if (!add_to_swap(page, page_list)) goto activate_locked; - lazyfree = true; may_enter_fs = 1; /* Adding to swap updated mapping */ @@ -1142,7 +1144,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, * The page is mapped into the page tables of one or more * processes. Try to unmap it here. */ - if (page_mapped(page) && mapping) { + if (page_mapped(page) && (mapping || lazyfree)) { switch (ret = try_to_unmap(page, lazyfree ? (ttu_flags | TTU_BATCH_FLUSH | TTU_LZFREE) : (ttu_flags | TTU_BATCH_FLUSH))) { @@ -1154,7 +1156,14 @@ static unsigned long shrink_page_list(struct list_head *page_list, case SWAP_MLOCK: goto cull_mlocked; case SWAP_LZFREE: - goto lazyfree; + /* follow __remove_mapping for reference */ + if (page_ref_freeze(page, 1)) { + if (!PageDirty(page)) + goto lazyfree; + else + page_ref_unfreeze(page, 1); + } + goto keep_locked; case SWAP_SUCCESS: ; /* try to free the page below */ } @@ -1266,10 +1275,9 @@ static unsigned long shrink_page_list(struct list_head *page_list, } } -lazyfree: if (!mapping || !__remove_mapping(mapping, page, true)) goto keep_locked; - +lazyfree: /* * At this point, we have no other references and there is * no way to pick any more up (removed from LRU, removed @@ -1294,6 +1302,8 @@ static unsigned long shrink_page_list(struct list_head *page_list, cull_mlocked: if (PageSwapCache(page)) try_to_free_swap(page); + if (lazyfree) + clear_page_lazyfree(page); unlock_page(page); list_add(&page->lru, &ret_pages); continue; @@ -1303,6 +1313,8 @@ static unsigned long shrink_page_list(struct list_head *page_list, if (PageSwapCache(page) && mem_cgroup_swap_full(page)) try_to_free_swap(page); VM_BUG_ON_PAGE(PageActive(page), page); + if (lazyfree) + clear_page_lazyfree(page); SetPageActive(page); pgactivate++; keep_locked: -- 2.9.3