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From: Greg KH <gregkh@suse.de>
To: linux-kernel@vger.kernel.org, stable@kernel.org
Cc: Ingo Molnar <mingo@elte.hu>,
	kexec@lists.infradead.org, Cliff Wickman <cpw@sgi.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	akpm@linux-foundation.org, torvalds@linux-foundation.org,
	stable-review@kernel.org, alan@lxorguk.ukuu.org.uk
Subject: [23/66] x86, kdump: Change copy_oldmem_page() to use cached addressing
Date: Fri, 19 Nov 2010 14:00:54 -0800	[thread overview]
Message-ID: <20101119220124.061070267@clark.site> (raw)
In-Reply-To: <20101119220309.GA15562@kroah.com>

2.6.36-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Cliff Wickman <cpw@sgi.com>

commit 37a2f9f30a360fb03522d15c85c78265ccd80287 upstream.

The copy of /proc/vmcore to a user buffer proceeds much faster
if the kernel addresses memory as cached.

With this patch we have seen an increase in transfer rate from
less than 15MB/s to 80-460MB/s, depending on size of the
transfer. This makes a big difference in time needed to save a
system dump.

Signed-off-by: Cliff Wickman <cpw@sgi.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: kexec@lists.infradead.org
LKML-Reference: <E1OtMLz-0001yp-Ia@eag09.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 arch/x86/kernel/crash_dump_64.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kernel/crash_dump_64.c
+++ b/arch/x86/kernel/crash_dump_64.c
@@ -34,7 +34,7 @@ ssize_t copy_oldmem_page(unsigned long p
 	if (!csize)
 		return 0;
 
-	vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
+	vaddr = ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE);
 	if (!vaddr)
 		return -ENOMEM;
 



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      parent reply	other threads:[~2010-11-19 22:04 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20101119220309.GA15562@kroah.com>
2010-11-19 22:00 ` [16/66] mm, x86: Saving vmcore with non-lazy freeing of vmas Greg KH
2010-11-19 22:00 ` Greg KH [this message]

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