From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx188.postini.com [74.125.245.188]) by kanga.kvack.org (Postfix) with SMTP id DA92E6B005A for ; Fri, 1 Jun 2012 10:24:39 -0400 (EDT) Date: Fri, 1 Jun 2012 09:24:37 -0500 From: Nathan Zimmer Subject: Re: [PATCH v2] tmpfs not interleaving properly Message-ID: <20120601142437.GA13739@gulag1.americas.sgi.com> References: <20120531143916.GA16162@gulag1.americas.sgi.com> <4FC7CFEB.5040009@gmail.com> <20120531132515.6af60152.akpm@linux-foundation.org> <4FC7D629.3090801@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4FC7D629.3090801@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: Andrew Morton , Nathan Zimmer , hughd@google.com, npiggin@gmail.com, cl@linux.com, lee.schermerhorn@hp.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org, riel@redhat.com On Thu, May 31, 2012 at 04:35:53PM -0400, KOSAKI Motohiro wrote: > (5/31/12 4:25 PM), Andrew Morton wrote: >> On Thu, 31 May 2012 16:09:15 -0400 >> KOSAKI Motohiro wrote: >> >>>> --- a/mm/shmem.c >>>> +++ b/mm/shmem.c >>>> @@ -929,7 +929,7 @@ static struct page *shmem_alloc_page(gfp_t gfp, >>>> /* >>>> * alloc_page_vma() will drop the shared policy reference >>>> */ >>>> - return alloc_page_vma(gfp,&pvma, 0); >>>> + return alloc_page_vma(gfp,&pvma, info->node_offset<< PAGE_SHIFT ); >>> >>> 3rd argument of alloc_page_vma() is an address. This is type error. >> >> Well, it's an unsigned long... >> >> But yes, it is conceptually wrong and *looks* weird. I think we can >> address that by overcoming our peculair aversion to documenting our >> code, sigh. This? > > Sorry, no. > > addr agrument of alloc_pages_vma() have two meanings. > > 1) interleave node seed > 2) look-up key of shmem policy > > I think this patch break (2). shmem_get_policy(pol, addr) assume caller honor to > pass correct address. But the pseudo vma we generated in shmem_alloc_page the vm_ops are set to NULL. So get_vma_policy will return the policy provided by the pseudo vma and not reach the shmem_get_policy. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org