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 97D04C6FD1D for ; Thu, 23 Mar 2023 04:10:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230038AbjCWEKj (ORCPT ); Thu, 23 Mar 2023 00:10:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229893AbjCWEKf (ORCPT ); Thu, 23 Mar 2023 00:10:35 -0400 Received: from mail-yb1-xb2e.google.com (mail-yb1-xb2e.google.com [IPv6:2607:f8b0:4864:20::b2e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 143373C0F for ; Wed, 22 Mar 2023 21:10:33 -0700 (PDT) Received: by mail-yb1-xb2e.google.com with SMTP id n125so23375860ybg.7 for ; Wed, 22 Mar 2023 21:10:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1679544632; 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=7lcSWN3GyBfovXV1vZTMtcIYaPrkreWXQ9n4Cq5J+k0=; b=rsH6Q3RSuOVN3v4OApWCK2fKM+hkdBWgfdvhHyQzW5Pw+plPTNi9t2m+UBHsGzWBhv Pk3rTZw8S6erq7968367WPneS5lOiBB263QMPQIVZosoB7XgLrX5yK+4fD9eP3bHitsO uvxzf7qEvXAmJrFSpdvQ60LIHlUll8cmFnmqKpFZ1USUIBElYfXVEPUVMOIKgSNihg2n nslvhDFRmKyaFgWa0Y1XYP6jxLvfUtJtMY/+Q2dg//gD1t2dlL7SklCJpgAJluQNrVEh IC06YYalM2n8mMSw7nA8J/qZlHYoX/dOLHyJZPURTxp1XDJGlwr9WTpY2AlVLpaX4gxi gAsg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679544632; 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=7lcSWN3GyBfovXV1vZTMtcIYaPrkreWXQ9n4Cq5J+k0=; b=37bNWIWPVtGcVZLk9GCk+Sn9rLj3WD8+72meykNOH8uJM9kIrwYbkKKAxILBINfdsZ yYU9gHoQlu0C4euGYKK3lMQI6XSfsZJohC40OZD1Ci8WqZCyYfeqoMil8WgGxYNNOIWc AKdI1xPlvMeRDhI5h05nDYMOeKE14m9x7MFCjkTR8fLgmvVJoJSzJLksuxOWQrkwmn6R U0FbQEACB1WkIKu8c+zSkvkhYlGpyZRpklvALeeoblD8Z+UzDyh8KnRBn1p0fJM7V3/U HRPFqXtopw3D7g4VuizdwSuzgatDSAD1LLL64JZBFNL/8LaN6okX0Osm5CwcESzZooxD G5rA== X-Gm-Message-State: AAQBX9fkVIQoyhFqJ9Y9Qjhb3Jq6AF4+rpjaB57HNG2SV07en7FJYbmS E3DznDo5E+MgUQShlmbbNSoZ7O90ja0wiGYf3CgT9A== X-Google-Smtp-Source: AKy350aqC2PVmbH/EfzdkoR2G9mhoQxC8Y2WiV+NG8rw6zMdlkFRbTKRx4Laq0LGQE/avEssQ3AobpebGV9qYqZK2AM= X-Received: by 2002:a25:800d:0:b0:b3b:6576:b22b with SMTP id m13-20020a25800d000000b00b3b6576b22bmr1346202ybk.12.1679544632180; Wed, 22 Mar 2023 21:10:32 -0700 (PDT) MIME-Version: 1.0 References: <20230323040037.2389095-1-yosryahmed@google.com> In-Reply-To: <20230323040037.2389095-1-yosryahmed@google.com> From: Shakeel Butt Date: Wed, 22 Mar 2023 21:10:21 -0700 Message-ID: Subject: Re: [RFC PATCH 0/7] Make rstat flushing IRQ and sleep friendly To: Yosry Ahmed Cc: Tejun Heo , Josef Bacik , Jens Axboe , Zefan Li , Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Andrew Morton , 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-kernel@vger.kernel.org On Wed, Mar 22, 2023 at 9:00=E2=80=AFPM Yosry Ahmed = wrote: > > Currently, if rstat flushing is invoked using the irqsafe variant > cgroup_rstat_flush_irqsafe(), we keep interrupts disabled and do not > sleep for the entire flush operation, which is O(# cpus * # cgroups). > This can be rather dangerous. > > Not all contexts that use cgroup_rstat_flush_irqsafe() actually cannot > sleep, and among those that cannot sleep, not all contexts require > interrupts to be disabled. Too many negations in the above sentence is making it very confusing.