From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e1.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id m3PJTitj014761 for ; Fri, 25 Apr 2008 15:29:44 -0400 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v8.7) with ESMTP id m3PJTiuS253174 for ; Fri, 25 Apr 2008 15:29:44 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m3PJThIp019968 for ; Fri, 25 Apr 2008 15:29:44 -0400 Date: Fri, 25 Apr 2008 12:29:42 -0700 From: Nishanth Aravamudan Subject: Re: [patch 02/18] hugetlb: factor out huge_new_page Message-ID: <20080425192942.GB14623@us.ibm.com> References: <20080423015302.745723000@nick.local0.net> <20080423015429.834926000@nick.local0.net> <20080424235431.GB4741@us.ibm.com> <20080424235829.GC4741@us.ibm.com> <481183FC.9060408@firstfloor.org> <20080425165424.GA9680@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Andi Kleen , npiggin@suse.de, akpm@linux-foundation.org, linux-mm@kvack.org, kniht@linux.vnet.ibm.com, abh@cray.com, wli@holomorphy.com List-ID: On 25.04.2008 [12:13:19 -0700], Christoph Lameter wrote: > On Fri, 25 Apr 2008, Nishanth Aravamudan wrote: > > > > >>> This happens to fix a minor bug. When alloc_bootmem_node returns > > > >>> a fallback node on a different node than passed the old code > > > >>> would have put it into the free lists of the wrong node. > > > >>> Now it would end up in the freelist of the correct node. > > > >> This is rather frustrating. The whole point of having the __GFP_THISNODE > > > >> flag is to indicate off-node allocations are *not* supported from the > > > >> caller... This was all worked on quite heavily a while back. > > > > > > Perhaps it was, but the result in hugetlb.c was not correct. > > > > Huh? There is a case in current code (current hugepage sizes) that > > allows __GFP_THISNODE to go off-node? > > Argh. Danger. SLAB will crash and/or corrupt data if that occurs. > > > > No, the bug is already there even without the bootmem patch. > > > > Where does alloc_pages_node go off-node? It is a bug in the core VM if > > it does, as we decided __GFP_THISNODE semantics with a nid specified > > indicates *no* fallback should occur. > > But this is only for bootmem right? SLAB is not using bootmem so we could > make an exception there. The issue is support of __GFP_THISNODE in the > bootmem allocator? I think so -- I'm not entirely sure. Andi, can you elucidate? Thanks, Nish -- Nishanth Aravamudan IBM Linux Technology Center -- 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