From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx152.postini.com [74.125.245.152]) by kanga.kvack.org (Postfix) with SMTP id D1FE56B002B for ; Wed, 17 Oct 2012 15:50:23 -0400 (EDT) Received: by mail-pb0-f41.google.com with SMTP id rq2so8557105pbb.14 for ; Wed, 17 Oct 2012 12:50:23 -0700 (PDT) Date: Wed, 17 Oct 2012 12:50:21 -0700 (PDT) From: David Rientjes Subject: Re: [patch for-3.7] mm, mempolicy: fix printing stack contents in numa_maps In-Reply-To: Message-ID: References: <20121008150949.GA15130@redhat.com> <20121017040515.GA13505@redhat.com> <507E4531.1070700@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: Kamezawa Hiroyuki , Dave Jones , Andrew Morton , Linus Torvalds , bhutchings@solarflare.com, Konstantin Khlebnikov , Naoya Horiguchi , Hugh Dickins , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Wed, 17 Oct 2012, KOSAKI Motohiro wrote: > > I think this refcounting is better than using task_lock(). > > I don't think so. get_vma_policy() is used from fast path. In other > words, number of > atomic ops is sensible for allocation performance. There are enhancements that we can make with refcounting: for instance, we may want to avoid doing it in the super-fast path when the policy is default_policy and then just do if (mpol != &default_policy) mpol_put(mpol); > Instead, I'd like > to use spinlock > for shared mempolicy instead of mutex. > Um, this was just changed to a mutex last week in commit b22d127a39dd ("mempolicy: fix a race in shared_policy_replace()") so that sp_alloc() can be done with GFP_KERNEL, so I didn't consider reverting that behavior. Are you nacking that patch, which you acked, now? -- 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