Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754153Ab0LVA1C (ORCPT ); Tue, 21 Dec 2010 19:27:02 -0500 Received: from mga01.intel.com ([192.55.52.88]:16542 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751863Ab0LVA1A (ORCPT ); Tue, 21 Dec 2010 19:27:00 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.60,210,1291622400"; d="scan'208";a="870656013" Subject: Re: [concept & "good taste" review] persistent store From: Huang Ying To: David Howells Cc: "Luck, Tony" , Borislav Petkov , Tony Luck , Linus Torvalds , "H. Peter Anvin" , "linux-kernel@vger.kernel.org" , "linux-arch@vger.kernel.org" , "tglx@linutronix.de" , "mingo@elte.hu" , "greg@kroah.com" , "akpm@linux-foundation.org" , David Miller , Alan Cox , Jim Keniston , Kyungmin Park , Geert Uytterhoeven In-Reply-To: <32058.1292926258@redhat.com> References: <1292892072.8743.70.camel@yhuang-dev> <1292813234.8743.66.camel@yhuang-dev> <4d0662e511688484b3@agluck-desktop.sc.intel.com> <4D0BEE1F.7020008@zytor.com> <20101219091752.GA16150@liondog.tnic> <17027.1292841992@redhat.com> <32058.1292926258@redhat.com> Content-Type: text/plain; charset="UTF-8" Date: Wed, 22 Dec 2010 08:26:56 +0800 Message-ID: <1292977616.8743.87.camel@yhuang-dev> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1516 Lines: 34 On Tue, 2010-12-21 at 18:10 +0800, David Howells wrote: > Huang Ying wrote: > > > > > - for OOPS messages will not cause system panic, it will go to disk and > > > > will not use up the persistent storage. > > > > > > You can't guarantee that an oops didn't just kill your ability to actually > > > write your syslog to disk or out across the network. > > > > I do not need to guarantee that. If the OOPS message can not be written > > to disk, just keeping it in persistent storage, and that is the very > > value of persistent storage. But for OOPS can go to disk safely, we do > > not need to waste persistent storage for it. > > My point is how do you know an oops message will actually manage to get to > disk? There's a userspace program (syslogd) between the kernel log and the > disk or network. The user space program (syslogd) is in my big picture, it will guarantee an oops meesage actually go to disk via something like fsync. After doing that, the user space program can erase the corresponding record in persistent storage to free the space. So all in all, oops messages not causing system panic or disk error will go to disk eventually and being freed and will not use up the persistent storage. Best Regards, Huang Ying -- 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/