From: Cliff Wickman Date: Thu, 16 Sep 2010 16:44:02 +0000 (-0500) Subject: mm, x86: Saving vmcore with non-lazy freeing of vmas X-Git-Tag: v2.6.37-rc1~203^2~9 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3ee48b6af49cf534ca2f481ecc484b156a41451d;p=pandora-kernel.git mm, x86: Saving vmcore with non-lazy freeing of vmas 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 Cc: Andrew Morton Cc: kexec@lists.infradead.org Cc: LKML-Reference: Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed