From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D25A4C0032E for ; Wed, 25 Oct 2023 23:50:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234976AbjJYXut (ORCPT ); Wed, 25 Oct 2023 19:50:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52636 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234980AbjJYXtd (ORCPT ); Wed, 25 Oct 2023 19:49:33 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A1D810F9 for ; Wed, 25 Oct 2023 16:49:11 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1847CC433C7; Wed, 25 Oct 2023 23:49:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1698277751; bh=3Eopx3z3Pt01b4dxacyAkFlO7lqQ/SKCQv2Bc3ZR1Go=; h=Date:To:From:Subject:From; b=rVss+1za6hLPpjMHO/HijtppWhc1l2DjFb3RbD0d9u/ZLxFT2p9ouRWyQYW4yPPcv XrUxJHCQ6Vh/TCsaCCChj1dOlChbPUBGrLzzCNfPc1OBJe27hLPj5RvLZuy+oLntLW CmtwGHA4/It7xskF8J69v7f7sHgRNRncfCpcTLBE= Date: Wed, 25 Oct 2023 16:49:10 -0700 To: mm-commits@vger.kernel.org, ziy@nvidia.com, ying.huang@intel.com, vbabka@suse.cz, mgorman@techsingularity.net, hughd@google.com, fengwei.yin@intel.com, baolin.wang@linux.alibaba.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-migrate-record-the-mlocked-page-status-to-remove-unnecessary-lru-drain.patch removed from -mm tree Message-Id: <20231025234911.1847CC433C7@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: mm: migrate: record the mlocked page status to remove unnecessary lru drain has been removed from the -mm tree. Its filename was mm-migrate-record-the-mlocked-page-status-to-remove-unnecessary-lru-drain.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Baolin Wang Subject: mm: migrate: record the mlocked page status to remove unnecessary lru drain Date: Sat, 21 Oct 2023 12:33:22 +0800 When doing compaction, I found the lru_add_drain() is an obvious hotspot when migrating pages. The distribution of this hotspot is as follows: - 18.75% compact_zone - 17.39% migrate_pages - 13.79% migrate_pages_batch - 11.66% migrate_folio_move - 7.02% lru_add_drain + 7.02% lru_add_drain_cpu + 3.00% move_to_new_folio 1.23% rmap_walk + 1.92% migrate_folio_unmap + 3.20% migrate_pages_sync + 0.90% isolate_migratepages The lru_add_drain() was added by commit c3096e6782b7 ("mm/migrate: __unmap_and_move() push good newpage to LRU") to drain the newpage to LRU immediately, to help to build up the correct newpage->mlock_count in remove_migration_ptes() for mlocked pages. However, if there are no mlocked pages are migrating, then we can avoid this lru drain operation, especailly for the heavy concurrent scenarios. So we can record the source pages' mlocked status in migrate_folio_unmap(), and only drain the lru list when the mlocked status is set in migrate_folio_move(). In addition, the page was already isolated from lru when migrating, so checking the mlocked status is stable by folio_test_mlocked() in migrate_folio_unmap(). After this patch, I can see the hotpot of the lru_add_drain() is gone: - 9.41% migrate_pages_batch - 6.15% migrate_folio_move - 3.64% move_to_new_folio + 1.80% migrate_folio_extra + 1.70% buffer_migrate_folio + 1.41% rmap_walk + 0.62% folio_add_lru + 3.07% migrate_folio_unmap Meanwhile, the compaction latency shows some improvements when running thpscale: base patched Amean fault-both-1 1131.22 ( 0.00%) 1112.55 * 1.65%* Amean fault-both-3 2489.75 ( 0.00%) 2324.15 * 6.65%* Amean fault-both-5 3257.37 ( 0.00%) 3183.18 * 2.28%* Amean fault-both-7 4257.99 ( 0.00%) 4079.04 * 4.20%* Amean fault-both-12 6614.02 ( 0.00%) 6075.60 * 8.14%* Amean fault-both-18 10607.78 ( 0.00%) 8978.86 * 15.36%* Amean fault-both-24 14911.65 ( 0.00%) 11619.55 * 22.08%* Amean fault-both-30 14954.67 ( 0.00%) 14925.66 * 0.19%* Amean fault-both-32 16654.87 ( 0.00%) 15580.31 * 6.45%* Link: https://lkml.kernel.org/r/06e9153a7a4850352ec36602df3a3a844de45698.1697859741.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Reviewed-by: "Huang, Ying" Reviewed-by: Zi Yan Cc: Hugh Dickins Cc: Mel Gorman Cc: Vlastimil Babka Cc: Yin Fengwei Signed-off-by: Andrew Morton --- mm/migrate.c | 48 +++++++++++++++++++++++++++++------------------- 1 file changed, 29 insertions(+), 19 deletions(-) --- a/mm/migrate.c~mm-migrate-record-the-mlocked-page-status-to-remove-unnecessary-lru-drain +++ a/mm/migrate.c @@ -1027,22 +1027,28 @@ union migration_ptr { struct anon_vma *anon_vma; struct address_space *mapping; }; + +enum { + PAGE_WAS_MAPPED = BIT(0), + PAGE_WAS_MLOCKED = BIT(1), +}; + static void __migrate_folio_record(struct folio *dst, - unsigned long page_was_mapped, + unsigned long old_page_state, struct anon_vma *anon_vma) { union migration_ptr ptr = { .anon_vma = anon_vma }; dst->mapping = ptr.mapping; - dst->private = (void *)page_was_mapped; + dst->private = (void *)old_page_state; } static void __migrate_folio_extract(struct folio *dst, - int *page_was_mappedp, + int *old_page_state, struct anon_vma **anon_vmap) { union migration_ptr ptr = { .mapping = dst->mapping }; *anon_vmap = ptr.anon_vma; - *page_was_mappedp = (unsigned long)dst->private; + *old_page_state = (unsigned long)dst->private; dst->mapping = NULL; dst->private = NULL; } @@ -1103,7 +1109,7 @@ static int migrate_folio_unmap(new_folio { struct folio *dst; int rc = -EAGAIN; - int page_was_mapped = 0; + int old_page_state = 0; struct anon_vma *anon_vma = NULL; bool is_lru = !__folio_test_movable(src); bool locked = false; @@ -1157,6 +1163,8 @@ static int migrate_folio_unmap(new_folio folio_lock(src); } locked = true; + if (folio_test_mlocked(src)) + old_page_state |= PAGE_WAS_MLOCKED; if (folio_test_writeback(src)) { /* @@ -1206,7 +1214,7 @@ static int migrate_folio_unmap(new_folio dst_locked = true; if (unlikely(!is_lru)) { - __migrate_folio_record(dst, page_was_mapped, anon_vma); + __migrate_folio_record(dst, old_page_state, anon_vma); return MIGRATEPAGE_UNMAP; } @@ -1232,11 +1240,11 @@ static int migrate_folio_unmap(new_folio VM_BUG_ON_FOLIO(folio_test_anon(src) && !folio_test_ksm(src) && !anon_vma, src); try_to_migrate(src, mode == MIGRATE_ASYNC ? TTU_BATCH_FLUSH : 0); - page_was_mapped = 1; + old_page_state |= PAGE_WAS_MAPPED; } if (!folio_mapped(src)) { - __migrate_folio_record(dst, page_was_mapped, anon_vma); + __migrate_folio_record(dst, old_page_state, anon_vma); return MIGRATEPAGE_UNMAP; } @@ -1248,7 +1256,8 @@ out: if (rc == -EAGAIN) ret = NULL; - migrate_folio_undo_src(src, page_was_mapped, anon_vma, locked, ret); + migrate_folio_undo_src(src, old_page_state & PAGE_WAS_MAPPED, + anon_vma, locked, ret); migrate_folio_undo_dst(dst, dst_locked, put_new_folio, private); return rc; @@ -1261,12 +1270,12 @@ static int migrate_folio_move(free_folio struct list_head *ret) { int rc; - int page_was_mapped = 0; + int old_page_state = 0; struct anon_vma *anon_vma = NULL; bool is_lru = !__folio_test_movable(src); struct list_head *prev; - __migrate_folio_extract(dst, &page_was_mapped, &anon_vma); + __migrate_folio_extract(dst, &old_page_state, &anon_vma); prev = dst->lru.prev; list_del(&dst->lru); @@ -1287,10 +1296,10 @@ static int migrate_folio_move(free_folio * isolated from the unevictable LRU: but this case is the easiest. */ folio_add_lru(dst); - if (page_was_mapped) + if (old_page_state & PAGE_WAS_MLOCKED) lru_add_drain(); - if (page_was_mapped) + if (old_page_state & PAGE_WAS_MAPPED) remove_migration_ptes(src, dst, false); out_unlock_both: @@ -1322,11 +1331,12 @@ out: */ if (rc == -EAGAIN) { list_add(&dst->lru, prev); - __migrate_folio_record(dst, page_was_mapped, anon_vma); + __migrate_folio_record(dst, old_page_state, anon_vma); return rc; } - migrate_folio_undo_src(src, page_was_mapped, anon_vma, true, ret); + migrate_folio_undo_src(src, old_page_state & PAGE_WAS_MAPPED, + anon_vma, true, ret); migrate_folio_undo_dst(dst, true, put_new_folio, private); return rc; @@ -1799,12 +1809,12 @@ out: dst = list_first_entry(&dst_folios, struct folio, lru); dst2 = list_next_entry(dst, lru); list_for_each_entry_safe(folio, folio2, &unmap_folios, lru) { - int page_was_mapped = 0; + int old_page_state = 0; struct anon_vma *anon_vma = NULL; - __migrate_folio_extract(dst, &page_was_mapped, &anon_vma); - migrate_folio_undo_src(folio, page_was_mapped, anon_vma, - true, ret_folios); + __migrate_folio_extract(dst, &old_page_state, &anon_vma); + migrate_folio_undo_src(folio, old_page_state & PAGE_WAS_MAPPED, + anon_vma, true, ret_folios); list_del(&dst->lru); migrate_folio_undo_dst(dst, true, put_new_folio, private); dst = dst2; _ Patches currently in -mm which might be from baolin.wang@linux.alibaba.com are