From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx167.postini.com [74.125.245.167]) by kanga.kvack.org (Postfix) with SMTP id 1A18E6B006E for ; Fri, 8 Jun 2012 03:03:26 -0400 (EDT) Received: by yenm7 with SMTP id m7so1366098yen.14 for ; Fri, 08 Jun 2012 00:03:25 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20120608065828.GA1515@lizard> References: <20120601122118.GA6128@lizard> <1338553446-22292-2-git-send-email-anton.vorontsov@linaro.org> <4FD170AA.10705@gmail.com> <20120608065828.GA1515@lizard> Date: Fri, 8 Jun 2012 10:03:24 +0300 Message-ID: Subject: Re: [PATCH 2/5] vmevent: Convert from deferred timer to deferred work From: Pekka Enberg Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Anton Vorontsov Cc: KOSAKI Motohiro , Leonid Moiseichuk , Bartlomiej Zolnierkiewicz , John Stultz , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org, patches@linaro.org, kernel-team@android.com On Fri, Jun 8, 2012 at 9:58 AM, Anton Vorontsov wrote: > If you're saying that we should set up a timer in the userland and > constantly read /proc/vmstat, then we will cause CPU wake up > every 100ms, which is not acceptable. Well, we can try to introduce > deferrable timers for the userspace. But then it would still add > a lot more overhead for our task, as this solution adds other two > context switches to read and parse /proc/vmstat. I guess this is > not a show-stopper though, so we can discuss this. > > Leonid, Pekka, what do you think about the idea? That's exactly the kind of half-assed ABI that lead to people inventing out-of-tree lowmem notifiers in the first place. I'd be more interested to know what people think of Minchan's that gets rid of vmstat sampling. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org