From: Wanpeng Li <liwanp@linux.vnet.ibm.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: akpm@linux-foundation.org, iamjoonsoo.kim@lge.com,
rientjes@google.com, zhangyanfei@cn.fujitsu.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
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"
Date: Tue, 17 Sep 2013 08:18:37 +0800 [thread overview]
Message-ID: <20130917001837.GA9692@hacker.(null)> (raw)
In-Reply-To: <523776D4.4070402@jp.fujitsu.com>
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.
>
>I wonder why we need to call setup_vmalloc_vm() _after_ insert_vmap_area.
I think it's another topic.
Fill vm_struct and set VM_VM_AREA flag. If I misunderstand your
question?
Regards,
Wanpeng Li
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next prev parent reply other threads:[~2013-09-17 0:18 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-14 23:45 [RESEND PATCH v5 1/4] mm/vmalloc: don't set area->caller twice Wanpeng Li
2013-09-14 23:45 ` [RESEND PATCH v5 2/4] mm/vmalloc: revert "mm/vmalloc.c: emit the failure message before return" Wanpeng Li
2013-09-16 20:15 ` KOSAKI Motohiro
2013-09-16 23:41 ` Wanpeng Li
2013-09-16 23:41 ` Wanpeng Li
[not found] ` <5237971b.4c19310a.2b36.7d41SMTPIN_ADDED_BROKEN@mx.google.com>
2013-09-17 5:39 ` KOSAKI Motohiro
2013-09-17 6:28 ` Wanpeng Li
2013-09-17 6:28 ` Wanpeng Li
2013-09-14 23:45 ` [RESEND PATCH v5 3/4] mm/vmalloc: revert "mm/vmalloc.c: check VM_UNINITIALIZED flag in s_show instead of show_numa_info" Wanpeng Li
2013-09-16 21:23 ` KOSAKI Motohiro
2013-09-17 0:18 ` Wanpeng Li [this message]
2013-09-17 0:18 ` Wanpeng Li
[not found] ` <52379fe8.c250e00a.63fd.ffff8ccdSMTPIN_ADDED_BROKEN@mx.google.com>
2013-09-17 5:44 ` KOSAKI Motohiro
2013-09-17 6:06 ` Wanpeng Li
2013-09-17 6:06 ` Wanpeng Li
2013-09-14 23:45 ` [RESEND PATCH v5 4/4] mm/vmalloc: fix show vmap_area information race with vmap_area tear down Wanpeng Li
2013-09-16 21:27 ` KOSAKI Motohiro
2013-09-16 23:25 ` Wanpeng Li
2013-09-16 23:25 ` Wanpeng Li
2013-09-16 19:52 ` [RESEND PATCH v5 1/4] mm/vmalloc: don't set area->caller twice KOSAKI Motohiro
2013-09-16 23:29 ` Wanpeng Li
2013-09-16 23:29 ` Wanpeng Li
[not found] ` <5237946f.4815440a.094e.ffff8c29SMTPIN_ADDED_BROKEN@mx.google.com>
2013-09-23 23:18 ` Andrew Morton
2013-09-24 0:01 ` Wanpeng Li
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