+Andrew On Tue, Nov 7, 2023 at 10:05 AM Roman Gushchin <roman.gushchin@xxxxxxxxx> wrote: > > On Mon, Nov 06, 2023 at 06:57:05PM -0800, Christoph Lameter wrote: > > Right.. Well lets add the cgoup folks to this. > > Hello! > > I think it's the best thing we can do now. Thoughts? > > From 5ed3e88f4f052b6ce8dbec0545dfc80eb7534a1a Mon Sep 17 00:00:00 2001 > From: Roman Gushchin <roman.gushchin@xxxxxxxxx> > Date: Tue, 7 Nov 2023 09:18:02 -0800 > Subject: [PATCH] mm: kmem: drop __GFP_NOFAIL when allocating objcg vectors > > Objcg vectors attached to slab pages to store slab object ownership > information are allocated using gfp flags for the original slab > allocation. Depending on slab page order and the size of slab objects, > objcg vector can take several pages. > > If the original allocation was done with the __GFP_NOFAIL flag, it > triggered a warning in the page allocation code. Indeed, order > 1 > pages should not been allocated with the __GFP_NOFAIL flag. > > Fix this by simple dropping the __GFP_NOFAIL flag when allocating *simply > the objcg vector. It effectively allows to skip the accounting of a > single slab object under a heavy memory pressure. > > An alternative would be to implement the mechanism to fallback to > order-0 allocations for accounting metadata, which is also not perfect > because it will increase performance penalty and memory footprint > of the kernel memory accounting under memory pressure. > > Reported-by: Christoph Lameter <cl@xxxxxxxxx> > Signed-off-by: Roman Gushchin <roman.gushchin@xxxxxxxxx> > Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> I think we should CC stable too. Acked-by: Shakeel Butt <shakeelb@xxxxxxxxxx> > --- > mm/memcontrol.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 774bd6e21e27..1c1061df9cd1 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2936,7 +2936,8 @@ void mem_cgroup_commit_charge(struct folio *folio, struct mem_cgroup *memcg) > * Moreover, it should not come from DMA buffer and is not readily > * reclaimable. So those GFP bits should be masked off. > */ > -#define OBJCGS_CLEAR_MASK (__GFP_DMA | __GFP_RECLAIMABLE | __GFP_ACCOUNT) > +#define OBJCGS_CLEAR_MASK (__GFP_DMA | __GFP_RECLAIMABLE | \ > + __GFP_ACCOUNT | __GFP_NOFAIL) > > /* > * mod_objcg_mlstate() may be called with irq enabled, so > -- > 2.42.0 >
