From: ebiederm@xmission.com (Eric W. Biederman)
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>,
vgoyal@redhat.com, akpm@linux-foundation.org, cpw@sgi.com,
kumagai-atsushi@mxc.nes.nec.co.jp, lisa.mitchell@hp.com,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
zhangyanfei@cn.fujitsu.com, jingbai.ma@hp.com,
linux-mm@kvack.org, riel@redhat.com, walken@google.com,
hughd@google.com, kosaki.motohiro@jp.fujitsu.com
Subject: Re: [PATCH v6 0/8] kdump, vmcore: support mmap() on /proc/vmcore
Date: Thu, 16 May 2013 21:29:03 -0700 [thread overview]
Message-ID: <87vc6icjqo.fsf@xmission.com> (raw)
In-Reply-To: <5195A223.2070204@zytor.com> (H. Peter Anvin's message of "Thu, 16 May 2013 20:21:07 -0700")
"H. Peter Anvin" <hpa@zytor.com> writes:
> On 05/16/2013 07:53 PM, Eric W. Biederman wrote:
>>
>> That is completely and totally orthogonal to this change.
>>
>> read_oldmem may have problems but in practice on a large systems those
>> problems are totally dwarfed by real life performance issues that come
>> from playing too much with the page tables.
>>
>> I really don't find bringing up whatever foundational issues you have
>> with read_oldmem() appropriate or relevant here.
>>
>
> Well, it is in the sense that we have two pieces of code doing the same
> thing, each with different bugs.
Not a the tiniest little bit.
All this patchset is about is which page table kernel vs user we map the
physical addresses in.
As such this patchset should neither increase nor decrease the number of
bugs, or cause any other hilarity.
Whatever theoretical issues you have with /dev/oldmem and /proc/vmcore
can and should be talked about and addressed independently of these
changes. HATMAYA Daisuke already has enough to handle coming up with a
clean set of patches that add mmap support.
Eric
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next prev parent reply other threads:[~2013-05-17 4:29 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-15 9:05 HATAYAMA Daisuke
2013-05-15 9:05 ` [PATCH v6 1/8] vmcore: clean up read_vmcore() HATAYAMA Daisuke
2013-05-15 9:33 ` Zhang Yanfei
2013-05-15 9:05 ` [PATCH v6 2/8] vmcore: allocate buffer for ELF headers on page-size alignment HATAYAMA Daisuke
2013-05-16 5:58 ` Zhang Yanfei
2013-05-16 16:51 ` Vivek Goyal
2013-05-17 0:08 ` HATAYAMA Daisuke
2013-05-15 9:05 ` [PATCH v6 3/8] vmcore: treat memory chunks referenced by PT_LOAD program header entries in page-size boundary in vmcore_list HATAYAMA Daisuke
2013-05-16 5:59 ` Zhang Yanfei
2013-05-15 9:06 ` [PATCH v6 4/8] vmalloc: make find_vm_area check in range HATAYAMA Daisuke
2013-05-15 21:37 ` KOSAKI Motohiro
2013-05-16 23:45 ` HATAYAMA Daisuke
2013-05-15 9:06 ` [PATCH v6 5/8] vmalloc: introduce remap_vmalloc_range_partial HATAYAMA Daisuke
2013-05-15 9:06 ` [PATCH v6 6/8] vmcore: allocate ELF note segment in the 2nd kernel vmalloc memory HATAYAMA Daisuke
2013-05-16 7:19 ` Zhang Yanfei
2013-05-16 20:32 ` Vivek Goyal
2013-05-16 23:47 ` HATAYAMA Daisuke
2013-05-15 9:06 ` [PATCH v6 7/8] vmcore: calculate vmcore file size from buffer size and total size of vmcore objects HATAYAMA Daisuke
2013-05-16 7:19 ` Zhang Yanfei
2013-05-15 9:06 ` [PATCH v6 8/8] vmcore: support mmap() on /proc/vmcore HATAYAMA Daisuke
2013-05-16 7:25 ` Zhang Yanfei
2013-05-16 20:44 ` Vivek Goyal
2013-05-17 0:06 ` [PATCH v6 0/8] kdump, " H. Peter Anvin
2013-05-17 1:45 ` HATAYAMA Daisuke
2013-05-17 2:53 ` Eric W. Biederman
2013-05-17 3:21 ` H. Peter Anvin
2013-05-17 4:29 ` Eric W. Biederman [this message]
2013-05-17 5:43 ` H. Peter Anvin
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