From: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
To: Dave Hansen <dave@sr71.net>
Cc: "kexec@lists.infradead.org" <kexec@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Thomas Renninger <trenn@suse.de>,
Simon Horman <horms@verge.net.au>,
"Eric W. Biederman" <ebiederm@xmission.com>,
"H. Peter Anvin" <hpa@zytor.com>, Yinghai Lu <yinghai@kernel.org>,
Cliff Wickman <cpw@sgi.com>, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH 5/5] kexec: X86: Pass memory ranges via e820 table instead of memmap= boot parameter
Date: Mon, 15 Apr 2013 16:58:08 +0900 [thread overview]
Message-ID: <516BB310.20209@jp.fujitsu.com> (raw)
In-Reply-To: <516B9714.80007@sr71.net>
(2013/04/15 14:58), Dave Hansen wrote:
> On 04/14/2013 09:52 PM, HATAYAMA Daisuke wrote:
>> This sounds like there's no such issue on x86 cache mechanism. Is it
>> correct? If so, what is the difference between ia64 and x86 cache
>> mechanisms?
>
> I'm just going by the code comments:
>
> drivers/char/mem.c
>> /*
>> * On ia64 if a page has been mapped somewhere as uncached, then
>> * it must also be accessed uncached by the kernel or data
>> * corruption may occur.
>> */
I think it reasonable, in complexity of design, to decide cache or
uncache according to whether target memory is RAM or some device. If
we're concerned about page levels, things are to be complicated further
since memory typing is done per pages. How large does such table become
to represent memory types for all the target pages, how do we create it
and when? (I don't know ia64 but I guess caching on ia64 is also done in
per pages just like x86...)
--
Thanks.
HATAYAMA, Daisuke
next prev parent reply other threads:[~2013-04-15 7:58 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1365683207-42425-1-git-send-email-trenn@suse.de>
[not found] ` <1365683207-42425-6-git-send-email-trenn@suse.de>
2013-04-11 14:55 ` [PATCH 5/5] kexec: X86: Pass memory ranges via e820 table instead of memmap= boot parameter Yinghai Lu
2013-04-11 15:06 ` H. Peter Anvin
2013-04-12 14:31 ` Vivek Goyal
2013-04-12 14:56 ` H. Peter Anvin
2013-04-12 22:17 ` Dave Hansen
2013-04-12 23:17 ` H. Peter Anvin
2013-04-15 4:52 ` HATAYAMA Daisuke
2013-04-15 5:58 ` Dave Hansen
2013-04-15 7:58 ` HATAYAMA Daisuke [this message]
2013-04-15 14:49 ` H. Peter Anvin
2013-04-12 12:24 ` Thomas Renninger
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