From: Christoph Lameter <cl@linux.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Mel Gorman <mel@csn.ul.ie>,
Linus Torvalds <torvalds@linux-foundation.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Minchan Kim <minchan.kim@gmail.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Rik van Riel <riel@redhat.com>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] mm,migration: Avoid race between shift_arg_pages() and rmap_walk() during migration by not migrating temporary stacks
Date: Wed, 12 May 2010 16:33:12 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.00.1005121627020.1273@router.home> (raw)
In-Reply-To: <20100512125427.d1b170ba.akpm@linux-foundation.org>
Still think this special casing is not that good.
One can also disable migration by providing a migration function that
always fails. One such function exists in mm/migrate.c:
/* Always fail migration. Used for mappings that are not movable */
int fail_migrate_page(struct address_space *mapping,
struct page *newpage, struct page *page)
{
return -EIO;
}
EXPORT_SYMBOL(fail_migrate_page);
The migration function is specified in
vma->vm_ops->migrate
If that is set to fail_migrate_page() then the pages in the vma will never
be migrated. XFS uses it f.e. to avoid page migration:
STATIC int
xfs_mapping_buftarg(
xfs_buftarg_t *btp,
struct block_device *bdev)
{
struct backing_dev_info *bdi;
struct inode *inode;
struct address_space *mapping;
static const struct address_space_operations mapping_aops = {
.sync_page = block_sync_page,
.migratepage = fail_migrate_page,
};
Would it not be possible to do something similar for the temporary stack?
--
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next prev parent reply other threads:[~2010-05-12 21:34 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-11 8:57 Mel Gorman
2010-05-11 12:10 ` Rik van Riel
2010-05-11 17:11 ` Linus Torvalds
2010-05-11 17:21 ` Rik van Riel
2010-05-12 0:23 ` KOSAKI Motohiro
2010-05-12 19:54 ` Andrew Morton
2010-05-12 20:51 ` Mel Gorman
2010-05-12 20:58 ` Andrew Morton
2010-05-12 23:06 ` KOSAKI Motohiro
2010-05-12 21:33 ` Christoph Lameter [this message]
2010-05-13 0:19 ` KAMEZAWA Hiroyuki
2010-05-13 17:22 ` Christoph Lameter
2010-05-13 23:51 ` KAMEZAWA Hiroyuki
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