diff options
| author | Cliff Wickman <cpw@sgi.com> | 2010-09-16 11:44:02 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-11-22 10:47:31 -0800 |
| commit | 9809892e2ccb494ad97599a018788f5abe8f7842 (patch) | |
| tree | 6d1e74277471662785b098c9fed0a1b34dea6ed6 /virt/kvm | |
| parent | 183308db7612a1b46a2b6355e83d93a4a8950771 (diff) | |
mm, x86: Saving vmcore with non-lazy freeing of vmas
commit 3ee48b6af49cf534ca2f481ecc484b156a41451d upstream.
During the reading of /proc/vmcore the kernel is doing
ioremap()/iounmap() repeatedly. And the buildup of un-flushed
vm_area_struct's is causing a great deal of overhead. (rb_next()
is chewing up most of that time).
This solution is to provide function set_iounmap_nonlazy(). It
causes a subsequent call to iounmap() to immediately purge the
vma area (with try_purge_vmap_area_lazy()).
With this patch we have seen the time for writing a 250MB
compressed dump drop from 71 seconds to 44 seconds.
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: kexec@lists.infradead.org
LKML-Reference: <E1OwHZ4-0005WK-Tw@eag09.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'virt/kvm')
0 files changed, 0 insertions, 0 deletions