Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757085Ab2JZH4B (ORCPT ); Fri, 26 Oct 2012 03:56:01 -0400 Received: from smtp30.kymp.net ([80.248.96.181]:33929 "EHLO smtp.kymp.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757053Ab2JZH4A (ORCPT ); Fri, 26 Oct 2012 03:56:00 -0400 X-Greylist: delayed 606 seconds by postgrey-1.27 at vger.kernel.org; Fri, 26 Oct 2012 03:56:00 EDT Date: Fri, 26 Oct 2012 10:45:47 +0300 From: Mika =?utf-8?Q?Bostr=C3=B6m?= To: Andrew Morton Cc: Dave Hansen , Michal Hocko , linux-mm@kvack.org, KAMEZAWA Hiroyuki , KOSAKI Motohiro , LKML Subject: Re: [PATCH] add some drop_caches documentation and info messsge Message-ID: <20121026074547.GA25935@bostik.iki.fi> Reply-To: Mika =?utf-8?Q?Bostr=C3=B6m?= References: <20121012125708.GJ10110@dhcp22.suse.cz> <20121023164546.747e90f6.akpm@linux-foundation.org> <20121024062938.GA6119@dhcp22.suse.cz> <20121024125439.c17a510e.akpm@linux-foundation.org> <50884F63.8030606@linux.vnet.ibm.com> <20121024134836.a28d223a.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20121024134836.a28d223a.akpm@linux-foundation.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1339 Lines: 28 On Wed, Oct 24, 2012 at 01:48:36PM -0700, Andrew Morton wrote: > Dave Hansen wrote: > > What kind of interface _is_ it in the first place? Is it really a > > production-level thing that we expect users to be poking at? Or, is it > > a rarely-used debugging and benchmarking knob which is fair game for us > > to tweak like this? > > It was a rarely-used mainly-developer-only thing which, apparently, real > people found useful at some point in the past. Perhaps we should never > have offered it. I've found it useful on occasion when generating large public keys. When key generation hangs due to not-enough-entropy, dropping all caches (followed by an intensive read) has allowed the system to collect enough entropy to let the key generation finish. Usefulness of the trick is probably going the way of the dodo, thanks to SSD's becoming more common. -- Mika Boström Individualisti, eksistentialisti, www.iki.fi/bostik rationalisti ja mulkvisti GPG: 0x2AED22CC; 6FC9 8375 31B7 3BA2 B5DC 484E F19F 8AD6 2AED 22CC -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/