On Tue, Jul 22, 2014 at 02:18:47PM +0900, Gioh Kim wrote: > Hello, > > This patch try to solve problem that a long-lasting page cache of > ext4 superblock disturbs page migration. > > I've been testing CMA feature on my ARM-based platform > and found some pages for page caches cannot be migrated. > Some of them are page caches of superblock of ext4 filesystem. > > Current ext4 reads superblock with sb_bread(). sb_bread() allocates page > from movable area. But the problem is that ext4 hold the page until > it is unmounted. If root filesystem is ext4 the page cannot be migrated forever. > > I introduce a new API for allocating page from non-movable area. > It is useful for ext4 and others that want to hold page cache for a long time. There's no word on why you can't teach ext4 to still migrate that page. For all I know it might be impossible, but at least mention why. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
