From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 9E26D6B01B3 for ; Tue, 23 Mar 2010 13:09:58 -0400 (EDT) Date: Tue, 23 Mar 2010 12:08:27 -0500 (CDT) From: Christoph Lameter Subject: Re: [PATCH 00 of 34] Transparent Hugepage support #14 In-Reply-To: <20100322171553.GS29874@random.random> Message-ID: References: <20100318234923.GV29874@random.random> <20100319144101.GB29874@random.random> <20100322163523.GA12407@cmpxchg.org> <20100322171553.GS29874@random.random> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Andrea Arcangeli Cc: Johannes Weiner , linux-mm@kvack.org, Marcelo Tosatti , Adam Litke , Avi Kivity , Izik Eidus , Hugh Dickins , Nick Piggin , Rik van Riel , Mel Gorman , Dave Hansen , Benjamin Herrenschmidt , Ingo Molnar , Mike Travis , KAMEZAWA Hiroyuki , Chris Wright , bpicco@redhat.com, KOSAKI Motohiro , Balbir Singh , Arnd Bergmann , "Michael S. Tsirkin" , Peter Zijlstra List-ID: On Mon, 22 Mar 2010, Andrea Arcangeli wrote: > Again: split_huge_page has nothing to do with the pte or pmd locking. But you are addinig sync points to the pte/pmd function... > Especially obvious in the case your proposed alternate design will > still use one form of split_huge_page but one that can fail if the > page is under gup (which would practically make it unusable anywhere > but swap and even in swap it would lead to potential livelocks in > unsolvable oom as it's not just slow-unfrequent-IO calling gup). It can fail and be retried. Breaking up a page is not a performance critical thing. As you have shown this occurs rarely. -- 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