Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751896Ab3IQFo2 (ORCPT ); Tue, 17 Sep 2013 01:44:28 -0400 Received: from mail-ea0-f174.google.com ([209.85.215.174]:55674 "EHLO mail-ea0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751130Ab3IQFoZ (ORCPT ); Tue, 17 Sep 2013 01:44:25 -0400 MIME-Version: 1.0 In-Reply-To: <52379fe8.c250e00a.63fd.ffff8ccdSMTPIN_ADDED_BROKEN@mx.google.com> References: <1379202342-23140-1-git-send-email-liwanp@linux.vnet.ibm.com> <1379202342-23140-3-git-send-email-liwanp@linux.vnet.ibm.com> <523776D4.4070402@jp.fujitsu.com> <52379fe8.c250e00a.63fd.ffff8ccdSMTPIN_ADDED_BROKEN@mx.google.com> From: KOSAKI Motohiro Date: Tue, 17 Sep 2013 01:44:04 -0400 X-Google-Sender-Auth: zirawOGDsKNb74Q9_kKtb3PFZSY Message-ID: Subject: Re: [RESEND PATCH v5 3/4] mm/vmalloc: revert "mm/vmalloc.c: check VM_UNINITIALIZED flag in s_show instead of show_numa_info" To: Wanpeng Li Cc: Andrew Morton , "iamjoonsoo.kim" , David Rientjes , zhangyanfei@cn.fujitsu.com, "linux-mm@kvack.org" , LKML Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1927 Lines: 48 On Mon, Sep 16, 2013 at 8:18 PM, Wanpeng Li wrote: > Hi KOSAKI, > On Mon, Sep 16, 2013 at 05:23:32PM -0400, KOSAKI Motohiro wrote: >>On 9/14/2013 7:45 PM, Wanpeng Li wrote: >>> Changelog: >>> *v2 -> v3: revert commit d157a558 directly >>> >>> The VM_UNINITIALIZED/VM_UNLIST flag introduced by commit f5252e00(mm: avoid >>> null pointer access in vm_struct via /proc/vmallocinfo) is used to avoid >>> accessing the pages field with unallocated page when show_numa_info() is >>> called. This patch move the check just before show_numa_info in order that >>> some messages still can be dumped via /proc/vmallocinfo. This patch revert >>> commit d157a558 (mm/vmalloc.c: check VM_UNINITIALIZED flag in s_show instead >>> of show_numa_info); >> >>Both d157a558 and your patch don't explain why your one is better. Yes, some >>messages _can_ be dumped. But why should we do so? > > More messages can be dumped and original commit f5252e00(mm: avoid null pointer > access in vm_struct via /proc/vmallocinfo) do that. > >>And No. __get_vm_area_node() doesn't use __GFP_ZERO for allocating vm_area_struct. >>dumped partial dump is not only partial, but also may be garbage. > > vm_struct is allocated by kzalloc_node. Oops, you are right. Then, your code _intentionally_ show amazing zero. Heh, nice. More message is pointless. zero is just zero. It doesn't have any information. >>I wonder why we need to call setup_vmalloc_vm() _after_ insert_vmap_area. > > I think it's another topic. Why? > Fill vm_struct and set VM_VM_AREA flag. If I misunderstand your > question? VM_VM_AREA doesn't help. we have race between insert_vmap_area and setup_vmalloc_vm. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/