From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WcGW3-0005Et-Tp for kexec@lists.infradead.org; Mon, 21 Apr 2014 15:52:20 +0000 Date: Mon, 21 Apr 2014 11:51:56 -0400 From: Vivek Goyal Subject: Re: [PATCH] makedumpfile: change the wrong code to calculate bufsize_cyclic for elf dump Message-ID: <20140421155156.GE4367@redhat.com> References: <20140414080239.GA8084@dhcp-16-105.nay.redhat.com> <20140416064445.GC8084@dhcp-16-105.nay.redhat.com> <0910DD04CBD6DE4193FCF86B9C00BE972048E6@BPXM01GP.gisp.nec.co.jp> <20140417045208.GE8084@dhcp-16-105.nay.redhat.com> <20140417050219.GF8084@dhcp-16-105.nay.redhat.com> <0910DD04CBD6DE4193FCF86B9C00BE9720542E@BPXM01GP.gisp.nec.co.jp> <20140418142912.GA2023@dhcp-17-102.nay.redhat.com> <20140418214133.2668464c@hananiah.suse.cz> <20140421151914.GD4367@redhat.com> <20140421174630.78565d63@hananiah.suse.cz> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20140421174630.78565d63@hananiah.suse.cz> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Petr Tesarik Cc: Atsushi Kumagai , "d.hatayama@jp.fujitsu.com" , "kexec@lists.infradead.org" , "zzou@redhat.com" , "bhe@redhat.com" On Mon, Apr 21, 2014 at 05:46:30PM +0200, Petr Tesarik wrote: > On Mon, 21 Apr 2014 11:19:14 -0400 > Vivek Goyal wrote: > > > On Fri, Apr 18, 2014 at 09:41:33PM +0200, Petr Tesarik wrote: > > > On Fri, 18 Apr 2014 22:29:12 +0800 > > > "bhe@redhat.com" wrote: > >[...] > > > > Instead, I am wondering how the 80% comes from, and why 20% of free > > > > memory must be safe. > > > > > > I believe these 80% come from the default value of vm.dirty_ratio, > > > > Actually I had suggested this 80% number when --cyclic feature was > > implemented. And I did not base it on dirty_ratio. Just a random > > suggestion. > > Hm. OK, you seem to have very good suggestions, even if they are > random. ;-) > > > > which is 20%. In other words, the kernel won't block further writes > > > until 20% of available RAM is used up by dirty cache. But if you > > > fill up all free memory with dirty pages and then touch another (though > > > allocated) page, the kernel will go into direct reclaim, and if nothing > > > can be written out ATM, it will invoke the OOM Killer. > > > > We can start playig with reducing dirty_raio too and see how does it go. > > Or use direct I/O... Is it still broken? May be if that turns out to be an issue. Or just reduce dirty_ratio to say 5 instead of default 20. Different things can be tried once we know what's the root cause of the issue. Thanks Vivek _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec