From: Tejun Heo Subject: Re: [PATCH cgroup/for-4.17 2/2] Subject: cgroup: Limit event generation frequency Date: Thu, 26 Apr 2018 14:35:14 -0700 Message-ID: <20180426213514.GV1911913@devbig577.frc2.facebook.com> References: <20180323194722.GE2149215@devbig577.frc2.facebook.com> <20180323194753.GF2149215@devbig577.frc2.facebook.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=g8dlQPSge40aMnv1pBkb8vhGJ6VgWEqkvQOVl6HmBW4=; b=NNFUeU8KxiQ2dOrtl38DUSuR/YHLXImGKfc5+2m+VeNoEImYUJTgBKNf1ZYD0oZ8mW 2yX/HgjxbBs0/wGLGj6wn04y0xIMTXSezGY4wRrntC1DoukNW3I9DqprIEiRmJKXl2qv gpoeOnZLAA6L90IxnuAgmm5Eql7RPK3Q1rcLTJ1SgUPW83O4MOaACcl5RTKlxvk5R1S1 nMLT0dCx+dVUMflMkw6o6Wyb38cXW/cL4YjR/YypDQEd7dgvwk48fLCPlQtguJxRfNjD +JYAui5a30eBQJQ6QtLxZvKNX9AHbsuLkSNVufYl83GELdxxu6vtQPgB835tkUxWvadB 0xTA== Content-Disposition: inline In-Reply-To: <20180323194753.GF2149215@devbig577.frc2.facebook.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Li Zefan , Johannes Weiner Cc: cgroups@vger.kernel.org, kernel-team@fb.com, linux-kernel@vger.kernel.org On Fri, Mar 23, 2018 at 12:47:53PM -0700, Tejun Heo wrote: > ".events" files generate file modified event to notify userland of > possible new events. Some of the events can be quite bursty > (e.g. memory high event) and generating notification each time is > costly and pointless. > > This patch implements a event rate limit mechanism. If a new > notification is requested before 10ms has passed since the previous > notification, the new notification is delayed till then. > > As this only delays from the second notification on in a given close > cluster of notifications, userland reactions to notifications > shouldn't be delayed at all in most cases while avoiding notification > storms. > > Signed-off-by: Tejun Heo Applied 1-2 to cgroup/for-4.18. Thanks. -- tejun