From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f50.google.com (mail-pa0-f50.google.com [209.85.220.50]) by kanga.kvack.org (Postfix) with ESMTP id BF7AB6B0035 for ; Mon, 4 Nov 2013 17:01:08 -0500 (EST) Received: by mail-pa0-f50.google.com with SMTP id fb1so7519828pad.37 for ; Mon, 04 Nov 2013 14:01:08 -0800 (PST) Received: from psmtp.com ([74.125.245.180]) by mx.google.com with SMTP id tu7si9759174pab.162.2013.11.04.14.01.07 for ; Mon, 04 Nov 2013 14:01:07 -0800 (PST) Date: Mon, 4 Nov 2013 14:01:04 -0800 From: Andrew Morton Subject: Re: [PATCH] mm: add strictlimit knob Message-Id: <20131104140104.7936d263258a7a6753eb325e@linux-foundation.org> In-Reply-To: <20131101142941.1161.40314.stgit@dhcp-10-30-17-2.sw.ru> References: <20131031142612.GA28003@kipc2.localdomain> <20131101142941.1161.40314.stgit@dhcp-10-30-17-2.sw.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Maxim Patlasov Cc: karl.kiniger@med.ge.com, jack@suse.cz, linux-kernel@vger.kernel.org, t.artem@lycos.com, linux-mm@kvack.org, mgorman@suse.de, tytso@mit.edu, fengguang.wu@intel.com, torvalds@linux-foundation.org, mpatlasov@parallels.com On Fri, 01 Nov 2013 18:31:40 +0400 Maxim Patlasov wrote: > "strictlimit" feature was introduced to enforce per-bdi dirty limits for > FUSE which sets bdi max_ratio to 1% by default: > > http://www.http.com//article.gmane.org/gmane.linux.kernel.mm/105809 > > However the feature can be useful for other relatively slow or untrusted > BDIs like USB flash drives and DVD+RW. The patch adds a knob to enable the > feature: > > echo 1 > /sys/class/bdi/X:Y/strictlimit > > Being enabled, the feature enforces bdi max_ratio limit even if global (10%) > dirty limit is not reached. Of course, the effect is not visible until > max_ratio is decreased to some reasonable value. I suggest replacing "max_ratio" here with the much more informative "/sys/class/bdi/X:Y/max_ratio". Also, Documentation/ABI/testing/sysfs-class-bdi will need an update please. > mm/backing-dev.c | 35 +++++++++++++++++++++++++++++++++++ > 1 file changed, 35 insertions(+) > I'm not really sure what to make of the patch. I assume you tested it and observed some effect. Could you please describe the test setup and the effects in some detail? -- 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