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 E55BEC6FD18 for ; Tue, 28 Mar 2023 15:20:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233936AbjC1PUm (ORCPT ); Tue, 28 Mar 2023 11:20:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40602 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233986AbjC1PUV (ORCPT ); Tue, 28 Mar 2023 11:20:21 -0400 Received: from mail-yb1-xb2c.google.com (mail-yb1-xb2c.google.com [IPv6:2607:f8b0:4864:20::b2c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3405AA5F8 for ; Tue, 28 Mar 2023 08:18:29 -0700 (PDT) Received: by mail-yb1-xb2c.google.com with SMTP id p204so15484933ybc.12 for ; Tue, 28 Mar 2023 08:18:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1680016702; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=+Oo7t3uH5L5XgCZ1uKSglRiPDhZouQp2W4do7dpcvfk=; b=sloJNSy6jcyr8V+bl2KDVZrUIx+CgEgGJSFJ4w5WaC8TdDbJCtG+r3mp7IA616+rDp vp5xon0cmgSmMxTl22bo4RSzS9zf/7Kn97mBl99ky4OeP2XRyg6onKPOdON3LsP3G/5l XANyH+1QqjNiVr6oKoANqKgz1Ajr/GLOPr3j2cYawyyWbFlBNgScTCm22rzxJwSb9p82 VRIEQDNvWgAhrcsWYx4ovZiheIKaE6I+lr3iNOLgZUWrzZB/z7jbm0dfyF5GYULBzeUy sOr3fI0aibAi2tvxQGwIW5wXdwecj11oK32tp95GWC1wSYzzlaWZF+3LUtQI/ppp1xXc o8Fw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680016702; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=+Oo7t3uH5L5XgCZ1uKSglRiPDhZouQp2W4do7dpcvfk=; b=t2G/CGLvHVvQYNxYhLua0nvnCqKAcneDjspF94n8zMGvqaU+gYpjf+qjlsx9pT9vpY BcblufiYFJ+/7Qb3dR9MGBFZTjLfMw5+M5oNYjd8J3CNg0VAUM1jrPjhnqQU9tkhYDh5 mYWDexq3hGpznyb4Jah1jbwvwn/0NigLLsE0rp0Rr7LVgdehNLy5BUyrepvjq5P7uUQm FzU1eazqTbVcoiZkxT6Kw2yeqLJneDmtEjqOwsHXCsDaO2TbBbskn9vjwEMR/KMLOr7i LHkLsoKXZnMp2Ga6OrIY6hDk9LlyfTKrm76vq82d/0aGITebmkmiLGwsAm149Bfh/M/Q 76Gg== X-Gm-Message-State: AAQBX9dERR4VZ2m1u9qmofr8USJv23jlGWnuOijzAGEfEUSAnA9IOG2l PEN1s+ejo7iUzMb888H8OBYRGS8vYI5hvtOKHotYx9i8dMDGTq3iATUVpg== X-Google-Smtp-Source: AKy350bj5Nyxts8ciOXLw5EWFV9sPrHyhrga3LXQMYyQcc2/rYEnNjc1hc6y50eir7QoYRZz6dOHo8zvJLKF9E3OnwA= X-Received: by 2002:a25:2749:0:b0:a99:de9d:d504 with SMTP id n70-20020a252749000000b00a99de9dd504mr10180174ybn.12.1680016702030; Tue, 28 Mar 2023 08:18:22 -0700 (PDT) MIME-Version: 1.0 References: <20230328061638.203420-1-yosryahmed@google.com> <20230328061638.203420-8-yosryahmed@google.com> In-Reply-To: <20230328061638.203420-8-yosryahmed@google.com> From: Shakeel Butt Date: Tue, 28 Mar 2023 08:18:11 -0700 Message-ID: Subject: Re: [PATCH v1 7/9] workingset: memcg: sleep when flushing stats in workingset_refault() To: Yosry Ahmed Cc: Tejun Heo , Josef Bacik , Jens Axboe , Zefan Li , Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Andrew Morton , =?UTF-8?Q?Michal_Koutn=C3=BD?= , Vasily Averin , cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Mon, Mar 27, 2023 at 11:16=E2=80=AFPM Yosry Ahmed wrote: > > In workingset_refault(), we call mem_cgroup_flush_stats_ratelimited() > to flush stats within an RCU read section and with sleeping disallowed. > Move the call to mem_cgroup_flush_stats_ratelimited() above the RCU read > section and allow sleeping to avoid unnecessarily performing a lot of > work without sleeping. > > Since workingset_refault() is the only caller of > mem_cgroup_flush_stats_ratelimited(), just make it call the non-atomic > mem_cgroup_flush_stats(). > > Signed-off-by: Yosry Ahmed A nit below: Acked-by: Shakeel Butt > --- > mm/memcontrol.c | 12 ++++++------ > mm/workingset.c | 4 ++-- > 2 files changed, 8 insertions(+), 8 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 57e8cbf701f3..0c0e74188e90 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -674,12 +674,6 @@ void mem_cgroup_flush_stats_atomic(void) > __mem_cgroup_flush_stats_atomic(); > } > > -void mem_cgroup_flush_stats_ratelimited(void) > -{ > - if (time_after64(jiffies_64, READ_ONCE(flush_next_time))) > - mem_cgroup_flush_stats_atomic(); > -} > - > /* non-atomic functions, only safe from sleepable contexts */ > static void __mem_cgroup_flush_stats(void) > { > @@ -695,6 +689,12 @@ void mem_cgroup_flush_stats(void) > __mem_cgroup_flush_stats(); > } > > +void mem_cgroup_flush_stats_ratelimited(void) > +{ > + if (time_after64(jiffies_64, READ_ONCE(flush_next_time))) > + mem_cgroup_flush_stats(); > +} > + > static void flush_memcg_stats_dwork(struct work_struct *w) > { > __mem_cgroup_flush_stats(); > diff --git a/mm/workingset.c b/mm/workingset.c > index af862c6738c3..7d7ecc46521c 100644 > --- a/mm/workingset.c > +++ b/mm/workingset.c > @@ -406,6 +406,8 @@ void workingset_refault(struct folio *folio, void *sh= adow) > unpack_shadow(shadow, &memcgid, &pgdat, &eviction, &workingset); > eviction <<=3D bucket_order; > > + /* Flush stats (and potentially sleep) before holding RCU read lo= ck */ I think the only reason we use rcu lock is due to mem_cgroup_from_id(). Maybe we should add mem_cgroup_tryget_from_id(). The other caller of mem_cgroup_from_id() in vmscan is already doing the same and could use mem_cgroup_tryget_from_id(). Though this can be done separately to this series (if we decide to do it at all). From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shakeel Butt Subject: Re: [PATCH v1 7/9] workingset: memcg: sleep when flushing stats in workingset_refault() Date: Tue, 28 Mar 2023 08:18:11 -0700 Message-ID: References: <20230328061638.203420-1-yosryahmed@google.com> <20230328061638.203420-8-yosryahmed@google.com> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1680016702; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=+Oo7t3uH5L5XgCZ1uKSglRiPDhZouQp2W4do7dpcvfk=; b=sloJNSy6jcyr8V+bl2KDVZrUIx+CgEgGJSFJ4w5WaC8TdDbJCtG+r3mp7IA616+rDp vp5xon0cmgSmMxTl22bo4RSzS9zf/7Kn97mBl99ky4OeP2XRyg6onKPOdON3LsP3G/5l XANyH+1QqjNiVr6oKoANqKgz1Ajr/GLOPr3j2cYawyyWbFlBNgScTCm22rzxJwSb9p82 VRIEQDNvWgAhrcsWYx4ovZiheIKaE6I+lr3iNOLgZUWrzZB/z7jbm0dfyF5GYULBzeUy sOr3fI0aibAi2tvxQGwIW5wXdwecj11oK32tp95GWC1wSYzzlaWZF+3LUtQI/ppp1xXc o8Fw== In-Reply-To: <20230328061638.203420-8-yosryahmed@google.com> List-ID: Content-Type: text/plain; charset="windows-1252" To: Yosry Ahmed Cc: Tejun Heo , Josef Bacik , Jens Axboe , Zefan Li , Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Andrew Morton , =?UTF-8?Q?Michal_Koutn=C3=BD?= , Vasily Averin , cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org On Mon, Mar 27, 2023 at 11:16=E2=80=AFPM Yosry Ahmed wrote: > > In workingset_refault(), we call mem_cgroup_flush_stats_ratelimited() > to flush stats within an RCU read section and with sleeping disallowed. > Move the call to mem_cgroup_flush_stats_ratelimited() above the RCU read > section and allow sleeping to avoid unnecessarily performing a lot of > work without sleeping. > > Since workingset_refault() is the only caller of > mem_cgroup_flush_stats_ratelimited(), just make it call the non-atomic > mem_cgroup_flush_stats(). > > Signed-off-by: Yosry Ahmed A nit below: Acked-by: Shakeel Butt > --- > mm/memcontrol.c | 12 ++++++------ > mm/workingset.c | 4 ++-- > 2 files changed, 8 insertions(+), 8 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 57e8cbf701f3..0c0e74188e90 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -674,12 +674,6 @@ void mem_cgroup_flush_stats_atomic(void) > __mem_cgroup_flush_stats_atomic(); > } > > -void mem_cgroup_flush_stats_ratelimited(void) > -{ > - if (time_after64(jiffies_64, READ_ONCE(flush_next_time))) > - mem_cgroup_flush_stats_atomic(); > -} > - > /* non-atomic functions, only safe from sleepable contexts */ > static void __mem_cgroup_flush_stats(void) > { > @@ -695,6 +689,12 @@ void mem_cgroup_flush_stats(void) > __mem_cgroup_flush_stats(); > } > > +void mem_cgroup_flush_stats_ratelimited(void) > +{ > + if (time_after64(jiffies_64, READ_ONCE(flush_next_time))) > + mem_cgroup_flush_stats(); > +} > + > static void flush_memcg_stats_dwork(struct work_struct *w) > { > __mem_cgroup_flush_stats(); > diff --git a/mm/workingset.c b/mm/workingset.c > index af862c6738c3..7d7ecc46521c 100644 > --- a/mm/workingset.c > +++ b/mm/workingset.c > @@ -406,6 +406,8 @@ void workingset_refault(struct folio *folio, void *sh= adow) > unpack_shadow(shadow, &memcgid, &pgdat, &eviction, &workingset); > eviction <<=3D bucket_order; > > + /* Flush stats (and potentially sleep) before holding RCU read lo= ck */ I think the only reason we use rcu lock is due to mem_cgroup_from_id(). Maybe we should add mem_cgroup_tryget_from_id(). The other caller of mem_cgroup_from_id() in vmscan is already doing the same and could use mem_cgroup_tryget_from_id(). Though this can be done separately to this series (if we decide to do it at all).