On Wed, Jan 5, 2011 at 3:47 PM, Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> wrote: > On Wed, 5 Jan 2011 13:48:50 +0900 > Minchan Kim <minchan.kim@xxxxxxxxx> wrote: > >> Hi, >> >> On Wed, Jan 5, 2011 at 1:00 PM, Daisuke Nishimura >> <nishimura@xxxxxxxxxxxxxxxxx> wrote: >> > Hi. >> > >> > This is a fix for a problem which has bothered me for a month. >> > >> > === >> > From: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> >> > >> > In current implimentation, mem_cgroup_end_migration() decides whether the page >> > migration has succeeded or not by checking "oldpage->mapping". >> > >> > But if we are tring to migrate a shmem swapcache, the page->mapping of it is >> > NULL from the begining, so the check would be invalid. >> > As a result, mem_cgroup_end_migration() assumes the migration has succeeded >> > even if it's not, so "newpage" would be freed while it's not uncharged