From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx128.postini.com [74.125.245.128]) by kanga.kvack.org (Postfix) with SMTP id 61A956B002B for ; Tue, 16 Oct 2012 19:39:50 -0400 (EDT) Received: by mail-oa0-f41.google.com with SMTP id k14so8418997oag.14 for ; Tue, 16 Oct 2012 16:39:49 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <20121008150949.GA15130@redhat.com> From: KOSAKI Motohiro Date: Tue, 16 Oct 2012 19:39:29 -0400 Message-ID: Subject: Re: mpol_to_str revisited. Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Dave Jones , Linux Kernel , bhutchings@solarflare.com, linux-mm@kvack.org, Linus Torvalds , Andrew Morton On Tue, Oct 16, 2012 at 2:10 AM, David Rientjes wrote: > On Tue, 16 Oct 2012, KOSAKI Motohiro wrote: > >> >> I don't think 80de7c3138ee9fd86a98696fd2cf7ad89b995d0a is right fix. >> > >> > It's certainly not a complete fix, but I think it's a much better result >> > of the race, i.e. we don't panic anymore, we simply fail the read() >> > instead. >> >> Even though 80de7c3138ee9fd86a98696fd2cf7ad89b995d0a itself is simple. It bring >> to caller complex. That's not good and have no worth. >> > > Before: the kernel panics, all workloads cease. > After: the file shows garbage, all workloads continue. > > This is better, in my opinion, but at best it's only a judgment call and > has no effect on anything. Kernel panics help to find our serious mistake. > I agree it would be better to respect the return value of mpol_to_str() > since there are other possible error conditions other than a freed > mempolicy, but let's not consider reverting 80de7c3138. It is obviously > not a full solution to the problem, though, and we need to serialize with > task_lock(). Sorry no. I will have to revert it. mempolicy have already a lot of meaningless complex and bring us a lot of problems. I haven't seen any reason adding more. > Dave, are you interested in coming up with a patch? -- 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