Messages in this thread | | | Date | Sat, 5 Jul 2008 15:11:46 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [PATCH] memcg: handle shmem's swap cache (Was 2.6.26-rc8-mm1 |
| |
On Sat, 05 Jul 2008 11:11:10 +0530 Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
> KAMEZAWA Hiroyuki wrote: > > My swapcache accounting under memcg patch failed to catch tmpfs(shmem)'s one. > > Can I test this under -mm tree ? > > (If -mm is busy, I'm not in hurry.) > > This patch works well in my box. > > = > > SwapCache handling fix. > > > > shmem's swapcache behavior is a little different from anonymous's one and > > memcg failed to handle it. This patch tries to fix it. > > > > After this: > > > > Any page marked as SwapCache is not uncharged. (delelte_from_swap_cache() > > delete the SwapCache flag.) > > > > To check a shmem-page-cache is alive or not we use > > page->mapping && !PageAnon(page) instead of > > pc->flags & PAGE_CGROUP_FLAG_CACHE. > > > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > > Though I am not opposed to this, I do sit up and think if keeping the reference > count around could avoid this complexity and from my point, the maintenance > overhead of this logic/code (I fear there might be more special cases :( )
yes, to me. but we have to fix..
But I don't like old code's refcnt handling which does - increment - does this increment was really neccesary ? No? ok, decrement it again.
This was much more complex to me than current code.
And old ones will needs the check at treating swap-cache. (it couldn't but if we want)
> > The trade-off is complexity versus the overhead of reference counting. > refcnt was also very complex ;)
Thanks, -Kame
> -- > Warm Regards, > Balbir Singh > Linux Technology Center > IBM, ISTL >
| |