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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 33C4DC11F6B for ; Fri, 2 Jul 2021 02:45:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1B7546140A for ; Fri, 2 Jul 2021 02:45:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234770AbhGBCrz (ORCPT ); Thu, 1 Jul 2021 22:47:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55054 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234627AbhGBCry (ORCPT ); Thu, 1 Jul 2021 22:47:54 -0400 Received: from mail-qt1-x834.google.com (mail-qt1-x834.google.com [IPv6:2607:f8b0:4864:20::834]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9A9AC061762; Thu, 1 Jul 2021 19:45:22 -0700 (PDT) Received: by mail-qt1-x834.google.com with SMTP id n9so5665508qtk.7; Thu, 01 Jul 2021 19:45:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=nOfujZpJs5bJ1Y1hAIj12f3/unKCESff8MCkIvriXAI=; b=RuVx54sI98pLBf6DbcXjoYQW0a+GwzvuRYR21hRtFGPJglZ19aPxpKxoOrHg1d3cAM uqXjy9ZYC6IHD3usEhZczLcAeVvEQUJBaAb5b9t9dU6jIzN59rjjDIrnV9NTG18Dlin4 2/hhgdVOYOsQfBnMaE5R/+Lpl4F5kW6AueKCisQ+MlhyVk17pgVevMuWkLhkDz2hmT7E 82/o3nGdd7ujb+1DVpa84CJIHZ7+sO+7zVUPyiJ4dNsvv3cNIxYerKjE/A63obmxrgeG WbeYQENN6ywD3agFrj8KUBdVEdx7j/KD77WkLIbcg2QYnEfjNUWY1mMsPhdazacWQ8Qt D9ug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=nOfujZpJs5bJ1Y1hAIj12f3/unKCESff8MCkIvriXAI=; b=VIYEk4Jn8vnAxUC7PbGaC+3XaK3DLPDD14Qm26n9bwzcgneg51wEkNGIoGUBh3adys Pc6jsv/mDFbzgBIhMFGdLR/1N1H7IppNKSHOenbSwMNCYtR2QBEtkFlC6KceweeeFUvJ GED6Ge7J1BwVjB4/3YXzyOWeQWlev6QHp9r3oDB9h1YZQ65MVvj/VHcOZ/LO2WrZJyIc /r4kgbw1Fr9TfP3U2a1IIzFxmvIKq5mOlPXHmn6TOfjkRnRZCTpnPCwbfcJFT6WBaYpO 3n+0NV8UKlml9wizclFl6QjjXxsD3vvkymQVTE/HCB++DU7CoyRIF85V0F0VSwluB5ZY CwwA== X-Gm-Message-State: AOAM532OWVKrTseOmvxt4xrC+rYQx6BYbs1uyjiygkVS3yUC3VhbBipE WTPeG7P7cBxfhlSvmcMtRk579GEjuCAplfS7MDvt16T5gm/0Xw== X-Google-Smtp-Source: ABdhPJzdKeXp/hkdB4Tj1wmnRZ8Y/zfm9GHei1xljO4BcdhplePgiV9DKq4olHz57Z4XjRuIcC3fDAR94XTbF7UEqEw= X-Received: by 2002:a05:622a:1451:: with SMTP id v17mr1720393qtx.286.1625193921736; Thu, 01 Jul 2021 19:45:21 -0700 (PDT) MIME-Version: 1.0 References: <20210630184624.9ca1937310b0dd5ce66b30e7@linux-foundation.org> <20210701015258.BrxjIzdE1%akpm@linux-foundation.org> In-Reply-To: From: Zhaoyang Huang Date: Fri, 2 Jul 2021 10:45:09 +0800 Message-ID: Subject: Re: [patch 108/192] mm: zram: amend SLAB_RECLAIM_ACCOUNT on zspage_cachep To: LKML Cc: Andrew Morton , "open list:MEMORY MANAGEMENT" , mm-commits@vger.kernel.org, Sergey Senozhatsky , torvalds@linux-foundation.org, Zhaoyang Huang Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 1, 2021 at 10:56 PM Minchan Kim wrote: > > On Wed, Jun 30, 2021 at 06:52:58PM -0700, Andrew Morton wrote: > > From: Zhaoyang Huang > > Subject: mm: zram: amend SLAB_RECLAIM_ACCOUNT on zspage_cachep > > > > Zspage_cachep is found be merged with other kmem cache during test, which > > is not good for debug things (zs_pool->zspage_cachep present to be another > > kmem cache in memory dumpfile). It is also neccessary to do so as > > shrinker has been registered for zspage. > > > > Amending this flag can help kernel to calculate SLAB_RECLAIMBLE correctly. > > > > Link: https://lkml.kernel.org/r/1623137297-29685-1-git-send-email-huangzhaoyang@gmail.com > > Signed-off-by: Zhaoyang Huang > > Cc: Minchan Kim > > Cc: Sergey Senozhatsky > > Signed-off-by: Andrew Morton > > Sorry for the late. I don't think this is correct. > > It's true "struct zspage" can be freed by zsmalloc's compaction registerred > by slab shrinker so tempted to make it SLAB_RECLAIM_ACCOUNT. However, it's > quite limited to work only when objects in the zspage are heavily fragmented. > Once the compaction is done, zspage are never discardable until objects are > fragmented again. It means it could hurt other reclaimable slab page reclaiming > since the zspage slab object pins the page. IMHO, kmem cache's reclaiming is NOT affected by SLAB_RECLAIM_ACCOUNT . This flag just affects kmem cache merge[1], the slab page's migrate type[2] and the page's statistics. Actually, zspage's cache DO merged with others even without SLAB_RECLAIM_ACCOUNT currently, which maybe cause zspage's object will NEVER be discarded.(SLAB_MERGE_SAME introduce confusions as people believe the cache will merge with others when it set and vice versa) [1] struct kmem_cache *find_mergeable(size_t size, size_t align, unsigned long flags, const char *name, void (*ctor)(void *)) ... if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME)) continue; [2] if (s->flags & SLAB_RECLAIM_ACCOUNT) s->allocflags |= __GFP_RECLAIMABLE; > > > --- > > > > mm/zsmalloc.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > --- a/mm/zsmalloc.c~mm-zram-amend-slab_reclaim_account-on-zspage_cachep > > +++ a/mm/zsmalloc.c > > @@ -328,7 +328,7 @@ static int create_cache(struct zs_pool * > > return 1; > > > > pool->zspage_cachep = kmem_cache_create("zspage", sizeof(struct zspage), > > - 0, 0, NULL); > > + 0, SLAB_RECLAIM_ACCOUNT, NULL); > > if (!pool->zspage_cachep) { > > kmem_cache_destroy(pool->handle_cachep); > > pool->handle_cachep = NULL; > > _ 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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 67C7DC11F6A for ; Fri, 2 Jul 2021 02:45:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EB32861407 for ; Fri, 2 Jul 2021 02:45:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EB32861407 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; 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Thu, 01 Jul 2021 19:45:21 -0700 (PDT) MIME-Version: 1.0 References: <20210630184624.9ca1937310b0dd5ce66b30e7@linux-foundation.org> <20210701015258.BrxjIzdE1%akpm@linux-foundation.org> In-Reply-To: From: Zhaoyang Huang Date: Fri, 2 Jul 2021 10:45:09 +0800 Message-ID: Subject: Re: [patch 108/192] mm: zram: amend SLAB_RECLAIM_ACCOUNT on zspage_cachep To: LKML Cc: Andrew Morton , "open list:MEMORY MANAGEMENT" , mm-commits@vger.kernel.org, Sergey Senozhatsky , torvalds@linux-foundation.org, Zhaoyang Huang Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=gmail.com header.s=20161025 header.b=RuVx54sI; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf14.hostedemail.com: domain of huangzhaoyang@gmail.com designates 209.85.160.180 as permitted sender) smtp.mailfrom=huangzhaoyang@gmail.com X-Stat-Signature: ygbwgbrh7q7xcwu9swo56awrqutzgupe X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 578226001A84 X-HE-Tag: 1625193922-488465 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: On Thu, Jul 1, 2021 at 10:56 PM Minchan Kim wrote: > > On Wed, Jun 30, 2021 at 06:52:58PM -0700, Andrew Morton wrote: > > From: Zhaoyang Huang > > Subject: mm: zram: amend SLAB_RECLAIM_ACCOUNT on zspage_cachep > > > > Zspage_cachep is found be merged with other kmem cache during test, which > > is not good for debug things (zs_pool->zspage_cachep present to be another > > kmem cache in memory dumpfile). It is also neccessary to do so as > > shrinker has been registered for zspage. > > > > Amending this flag can help kernel to calculate SLAB_RECLAIMBLE correctly. > > > > Link: https://lkml.kernel.org/r/1623137297-29685-1-git-send-email-huangzhaoyang@gmail.com > > Signed-off-by: Zhaoyang Huang > > Cc: Minchan Kim > > Cc: Sergey Senozhatsky > > Signed-off-by: Andrew Morton > > Sorry for the late. I don't think this is correct. > > It's true "struct zspage" can be freed by zsmalloc's compaction registerred > by slab shrinker so tempted to make it SLAB_RECLAIM_ACCOUNT. However, it's > quite limited to work only when objects in the zspage are heavily fragmented. > Once the compaction is done, zspage are never discardable until objects are > fragmented again. It means it could hurt other reclaimable slab page reclaiming > since the zspage slab object pins the page. IMHO, kmem cache's reclaiming is NOT affected by SLAB_RECLAIM_ACCOUNT . This flag just affects kmem cache merge[1], the slab page's migrate type[2] and the page's statistics. Actually, zspage's cache DO merged with others even without SLAB_RECLAIM_ACCOUNT currently, which maybe cause zspage's object will NEVER be discarded.(SLAB_MERGE_SAME introduce confusions as people believe the cache will merge with others when it set and vice versa) [1] struct kmem_cache *find_mergeable(size_t size, size_t align, unsigned long flags, const char *name, void (*ctor)(void *)) ... if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME)) continue; [2] if (s->flags & SLAB_RECLAIM_ACCOUNT) s->allocflags |= __GFP_RECLAIMABLE; > > > --- > > > > mm/zsmalloc.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > --- a/mm/zsmalloc.c~mm-zram-amend-slab_reclaim_account-on-zspage_cachep > > +++ a/mm/zsmalloc.c > > @@ -328,7 +328,7 @@ static int create_cache(struct zs_pool * > > return 1; > > > > pool->zspage_cachep = kmem_cache_create("zspage", sizeof(struct zspage), > > - 0, 0, NULL); > > + 0, SLAB_RECLAIM_ACCOUNT, NULL); > > if (!pool->zspage_cachep) { > > kmem_cache_destroy(pool->handle_cachep); > > pool->handle_cachep = NULL; > > _