[Devel] Re: problem with ZONE_MOVABLE.

[Andrew Morton]

On Thu, 13 Sep 2007 16:00:06 +0530
Balbir Singh <balbir at linux.vnet.ibm.com> wrote:

> KAMEZAWA Hiroyuki wrote:
> > Hi, 
> > 
> > While I'm playing with memory controller of 2.6.23-rc4-mm1, I met following.
> > 
> > ==
> > [root at drpq test-2.6.23-rc4-mm1]# echo $$ > /opt/mem_control/group_1/tasks
> > [root at drpq test-2.6.23-rc4-mm1]# cat /opt/mem_control/group_1/memory.limit
> > 32768
> > [root at drpq test-2.6.23-rc4-mm1]# cat /opt/mem_control/group_1/memory.usage
> > 286
> > // Memory is limited to 512 GiB. try "dd" 1GiB (page size is 16KB)
> > 
> > [root at drpq test-2.6.23-rc4-mm1]# dd if=/dev/zero of=/tmp/tmpfile bs=1024 count=1048576
> > Killed
> > [root at drpq test-2.6.23-rc4-mm1]# ls
> > Killed
> > //above are caused by OOM.
> > [root at drpq test-2.6.23-rc4-mm1]# cat /opt/mem_control/group_1/memory.usage
> > 32763
> > [root at drpq test-2.6.23-rc4-mm1]# cat /opt/mem_control/group_1/memory.limit
> > 32768
> > // fully filled by page cache. no reclaim run.
> > ==
> > 
> > The reason  this happens is  because I used kernelcore= boot option, i.e
> > ZONE_MOVABLE. Seems try_to_free_mem_container_pages() ignores ZONE_MOVABLE.
> > 
> > Quick fix is attached, but Mel's one-zonelist-pernode patch may change this.
> > I'll continue to watch.
> > 
> > Thanks,
> > -Kame
> > ==
> > Now, there is ZONE_MOVABLE...
> > 
> > page cache and user pages are allocated from gfp_zone(GFP_HIGHUSER_MOVABLE)
> > 
> > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
> > ---
> >  mm/vmscan.c |    9 ++-------
> >  1 file changed, 2 insertions(+), 7 deletions(-)
> > 
> > Index: linux-2.6.23-rc4-mm1.bak/mm/vmscan.c
> > ===================================================================
> > --- linux-2.6.23-rc4-mm1.bak.orig/mm/vmscan.c
> > +++ linux-2.6.23-rc4-mm1.bak/mm/vmscan.c
> > @@ -1351,12 +1351,6 @@ unsigned long try_to_free_pages(struct z
> > 
> >  #ifdef CONFIG_CONTAINER_MEM_CONT
> > 
> > -#ifdef CONFIG_HIGHMEM
> > -#define ZONE_USERPAGES ZONE_HIGHMEM
> > -#else
> > -#define ZONE_USERPAGES ZONE_NORMAL
> > -#endif
> > -
> >  unsigned long try_to_free_mem_container_pages(struct mem_container *mem_cont)
> >  {
> >  	struct scan_control sc = {
> > @@ -1371,9 +1365,10 @@ unsigned long try_to_free_mem_container_
> >  	};
> >  	int node;
> >  	struct zone **zones;
> > +	int target_zone = gfp_zone(GFP_HIGHUSER_MOVABLE);
> > 
> >  	for_each_online_node(node) {
> > -		zones = NODE_DATA(node)->node_zonelists[ZONE_USERPAGES].zones;
> > +		zones = NODE_DATA(node)->node_zonelists[target_zone].zones;
> >  		if (do_try_to_free_pages(zones, sc.gfp_mask, &sc))
> >  			return 1;
> >  	}
> 
> Mel, has sent out a fix (for the single zonelist) that conflicts with
> this one. Your fix looks correct to me, but it will be over ridden
> by Mel's fix (once those patches are in -mm).
> 

"mel's fix" is rather too imprecise a term for me to make head or tail of this.

Oh well, the patch basically applied, so I whacked it in there, designated
as to be folded into memory-controller-make-charging-gfp-mask-aware.patch
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