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 X-Spam-Level: X-Spam-Status: No, score=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2D58CC433DB for ; Wed, 24 Feb 2021 08:06:58 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7C10564EC9 for ; Wed, 24 Feb 2021 08:06:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7C10564EC9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id EFF0B6B006E; Wed, 24 Feb 2021 03:06:56 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E876E6B0070; Wed, 24 Feb 2021 03:06:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D757C6B0071; Wed, 24 Feb 2021 03:06:56 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0098.hostedemail.com [216.40.44.98]) by kanga.kvack.org (Postfix) with ESMTP id BBDEE6B006E for ; Wed, 24 Feb 2021 03:06:56 -0500 (EST) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 78379180ACF76 for ; Wed, 24 Feb 2021 08:06:56 +0000 (UTC) X-FDA: 77852430432.02.7A0D1A0 Received: from out30-43.freemail.mail.aliyun.com (out30-43.freemail.mail.aliyun.com [115.124.30.43]) by imf14.hostedemail.com (Postfix) with ESMTP id 7F685C000C45 for ; Wed, 24 Feb 2021 08:06:44 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R171e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04423;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=11;SR=0;TI=SMTPD_---0UPR-KCg_1614154005; Received: from IT-FVFX43SYHV2H.local(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0UPR-KCg_1614154005) by smtp.aliyun-inc.com(127.0.0.1); Wed, 24 Feb 2021 16:06:46 +0800 Subject: Re: [PATCH v2 03/10] mm: don't pass "enum lru_list" to lru list addition functions To: Yu Zhao , Andrew Morton , Matthew Wilcox , Vlastimil Babka Cc: Hugh Dickins , Michal Hocko , Johannes Weiner , Vladimir Davydov , Roman Gushchin , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20210122220600.906146-1-yuzhao@google.com> <20210122220600.906146-4-yuzhao@google.com> <20210126220111.GO308988@casper.infradead.org> <20210223145011.0181eed96ab0091a493b51f6@linux-foundation.org> From: Alex Shi Message-ID: Date: Wed, 24 Feb 2021 16:06:45 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.0; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=gbk X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 7F685C000C45 X-Stat-Signature: xt8bxqe1t8ysuisigmw7rumoyenskk1b Received-SPF: none (linux.alibaba.com>: No applicable sender policy available) receiver=imf14; identity=mailfrom; envelope-from=""; helo=out30-43.freemail.mail.aliyun.com; client-ip=115.124.30.43 X-HE-DKIM-Result: none/none X-HE-Tag: 1614154004-97274 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: =D4=DA 2021/2/24 =CF=C2=CE=E71:29, Yu Zhao =D0=B4=B5=C0: > On Tue, Feb 23, 2021 at 02:50:11PM -0800, Andrew Morton wrote: >> On Tue, 26 Jan 2021 15:14:38 -0700 Yu Zhao wrote: >> >>> On Tue, Jan 26, 2021 at 10:01:11PM +0000, Matthew Wilcox wrote: >>>> On Fri, Jan 22, 2021 at 03:05:53PM -0700, Yu Zhao wrote: >>>>> +++ b/mm/swap.c >>>>> @@ -231,7 +231,7 @@ static void pagevec_move_tail_fn(struct page *p= age, struct lruvec *lruvec) >>>>> if (!PageUnevictable(page)) { >>>>> del_page_from_lru_list(page, lruvec, page_lru(page)); >>>>> ClearPageActive(page); >>>>> - add_page_to_lru_list_tail(page, lruvec, page_lru(page)); >>>>> + add_page_to_lru_list_tail(page, lruvec); >>>>> __count_vm_events(PGROTATED, thp_nr_pages(page)); >>>>> } >>>> >>>> Is it profitable to do ... >>>> >>>> - del_page_from_lru_list(page, lruvec, page_lru(page)); >>>> + enum lru_list lru =3D page_lru(page); >>>> + del_page_from_lru_list(page, lruvec, lru); >>>> ClearPageActive(page); >>>> - add_page_to_lru_list_tail(page, lruvec, page_lru(page)); >>>> + lru &=3D ~LRU_ACTIVE; >>>> + add_page_to_lru_list_tail(page, lruvec, lru); >>> >>> Ok, now we want to trade readability for size. Sure, I'll see how >>> much we could squeeze. >> >> As nothing has happened here and the code bloat issue remains, I'll >> hold this series out of 5.12-rc1. >=20 > Sorry for the slow response. I was trying to ascertain why > page_lru(), a tiny helper, could bloat vmlinux by O(KB). It turned out > compound_head() included in Page{Active,Unevictable} is a nuisance in > our case. Testing PG_{active,unevictable} against > compound_head(page)->flags is really unnecessary because all lru > operations are eventually done on page->lru not > compound_head(page)->lru. With the following change, which sacrifices > the readability a bit, we gain 998 bytes with Clang but lose 227 bytes > with GCC, which IMO is a win. (We use Clang by default.) >=20 >=20 > diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h > index 355ea1ee32bd..ec0878a3cdfe 100644 > --- a/include/linux/mm_inline.h > +++ b/include/linux/mm_inline.h > @@ -46,14 +46,12 @@ static __always_inline void __clear_page_lru_flags(= struct page *page) > { > VM_BUG_ON_PAGE(!PageLRU(page), page); > =20 > - __ClearPageLRU(page); > - > /* this shouldn't happen, so leave the flags to bad_page() */ > - if (PageActive(page) && PageUnevictable(page)) > + if ((page->flags & (BIT(PG_active) | BIT(PG_unevictable))) =3D=3D > + (BIT(PG_active) | BIT(PG_unevictable))) > return; > =20 > - __ClearPageActive(page); > - __ClearPageUnevictable(page); > + page->flags &=3D ~(BIT(PG_lru) | BIT(PG_active) | BIT(PG_unevictable)= ); > } > =20 > /** > @@ -65,18 +63,12 @@ static __always_inline void __clear_page_lru_flags(= struct page *page) > */ > static __always_inline enum lru_list page_lru(struct page *page) > { > - enum lru_list lru; > + unsigned long flags =3D READ_ONCE(page->flags); > =20 > VM_BUG_ON_PAGE(PageActive(page) && PageUnevictable(page), page); > =20 > - if (PageUnevictable(page)) > - return LRU_UNEVICTABLE; > - > - lru =3D page_is_file_lru(page) ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANO= N; > - if (PageActive(page)) > - lru +=3D LRU_ACTIVE; > - > - return lru; > + return (flags & BIT(PG_unevictable)) ? LRU_UNEVICTABLE : > + (LRU_FILE * !(flags & BIT(PG_swapbacked)) + !!(flags & BIT(PG_= active))); Currently each of page flags used different flags policy, does this mean = above flags could be change to PF_ANY policy? Thanks Alex > } > =20 > static __always_inline void add_page_to_lru_list(struct page *page, >=20 >=20 > I'll post this as a separate patch. Below the bloat-o-meter collected > on top of c03c21ba6f4e. >=20 > $ ./scripts/bloat-o-meter ../vmlinux.clang.orig ../vmlinux.clang > add/remove: 0/1 grow/shrink: 7/10 up/down: 191/-1189 (-998) > Function old new delta > lru_lazyfree_fn 848 893 +45 > lru_deactivate_file_fn 1037 1075 +38 > perf_trace_mm_lru_insertion 515 548 +33 > check_move_unevictable_pages 983 1006 +23 > __activate_page 706 729 +23 > trace_event_raw_event_mm_lru_insertion 476 497 +21 > lru_deactivate_fn 691 699 +8 > __bpf_trace_mm_lru_insertion 13 11 -2 > __traceiter_mm_lru_insertion 67 62 -5 > move_pages_to_lru 964 881 -83 > __pagevec_lru_add_fn 665 581 -84 > isolate_lru_page 524 419 -105 > __munlock_pagevec 1609 1481 -128 > isolate_migratepages_block 3370 3237 -133 > __page_cache_release 556 413 -143 > lruvec_lru_size 151 - -151 > release_pages 1025 866 -159 > pagevec_move_tail_fn 805 609 -196 > Total: Before=3D19502982, After=3D19501984, chg -0.01% >=20 > $ ./scripts/bloat-o-meter ../vmlinux.gcc.orig ../vmlinux.gcc > add/remove: 0/1 grow/shrink: 9/9 up/down: 1010/-783 (227) > Function old new delta > shrink_lruvec 1690 1950 +260 > lru_deactivate_file_fn 961 1128 +167 > isolate_migratepages_block 3286 3427 +141 > check_move_unevictable_pages 1042 1170 +128 > lru_lazyfree_fn 709 822 +113 > lru_deactivate_fn 665 724 +59 > __activate_page 703 760 +57 > trace_event_raw_event_mm_lru_insertion 432 478 +46 > perf_trace_mm_lru_insertion 464 503 +39 > __bpf_trace_mm_lru_insertion 13 11 -2 > __traceiter_mm_lru_insertion 66 57 -9 > isolate_lru_page 472 405 -67 > __munlock_pagevec 1282 1212 -70 > __pagevec_lru_add 976 893 -83 > __page_cache_release 508 418 -90 > release_pages 978 887 -91 > move_pages_to_lru 954 853 -101 > lruvec_lru_size 131 - -131 > pagevec_move_tail_fn 770 631 -139 > Total: Before=3D19237248, After=3D19237475, chg +0.00% >=20