[Cc Roman] On Sun 14-06-20 14:38:58, Muchun Song wrote: > When a kmem_cache is initialized with SLAB_ACCOUNT slab flag, we must > not call kmem_cache_alloc with __GFP_ACCOUNT GFP flag. In this case, > we can be accounted to kmemcg twice. This is not correct. So we add a > __GFP_ACCOUNT GFP flag check for slab allocation. > > We also introduce a new helper named fixup_gfp_flags to do that check. > We can reuse the fixup_gfp_flags for SLAB/SLUB. > > Signed-off-by: Muchun Song <[email protected]> > --- > mm/slab.c | 10 +--------- > mm/slab.h | 21 +++++++++++++++++++++ > mm/slub.c | 10 +--------- > 3 files changed, 23 insertions(+), 18 deletions(-) > > diff --git a/mm/slab.c b/mm/slab.c > index 9350062ffc1a..6e0110bef2d6 100644 > --- a/mm/slab.c > +++ b/mm/slab.c > @@ -126,8 +126,6 @@ > > #include <trace/events/kmem.h> > > -#include "internal.h" > - > #include "slab.h" > > /* > @@ -2579,13 +2577,7 @@ static struct page *cache_grow_begin(struct kmem_cache > *cachep, > * Be lazy and only check for valid flags here, keeping it out of the > * critical path in kmem_cache_alloc(). > */ > - if (unlikely(flags & GFP_SLAB_BUG_MASK)) { > - gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK; > - flags &= ~GFP_SLAB_BUG_MASK; > - pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x > (%pGg). Fix your code!\n", > - invalid_mask, &invalid_mask, flags, &flags); > - dump_stack(); > - } > + flags = fixup_gfp_flags(cachep, flags); > WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO)); > local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK); > > diff --git a/mm/slab.h b/mm/slab.h > index 815e4e9a94cd..0b91f2a7b033 100644 > --- a/mm/slab.h > +++ b/mm/slab.h > @@ -109,6 +109,7 @@ struct memcg_cache_params { > #include <linux/kmemleak.h> > #include <linux/random.h> > #include <linux/sched/mm.h> > +#include "internal.h" > > /* > * State of the slab allocator. > @@ -627,6 +628,26 @@ struct kmem_cache_node { > > }; > > +static inline gfp_t fixup_gfp_flags(struct kmem_cache *s, gfp_t flags) > +{ > + gfp_t invalid_mask = 0; > + > + if (unlikely(flags & GFP_SLAB_BUG_MASK)) > + invalid_mask |= flags & GFP_SLAB_BUG_MASK; > + > + if (unlikely(flags & __GFP_ACCOUNT && s->flags & SLAB_ACCOUNT)) > + invalid_mask |= __GFP_ACCOUNT; > + > + if (unlikely(invalid_mask)) { > + flags &= ~invalid_mask; > + pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x > (%pGg). Fix your code!\n", > + invalid_mask, &invalid_mask, flags, &flags); > + dump_stack(); > + } > + > + return flags; > +} > + > static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int > node) > { > return s->node[node]; > diff --git a/mm/slub.c b/mm/slub.c > index b8f798b50d44..49b5cb7da318 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -37,8 +37,6 @@ > > #include <trace/events/kmem.h> > > -#include "internal.h" > - > /* > * Lock order: > * 1. slab_mutex (Global Mutex) > @@ -1745,13 +1743,7 @@ static struct page *allocate_slab(struct kmem_cache > *s, gfp_t flags, int node) > > static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node) > { > - if (unlikely(flags & GFP_SLAB_BUG_MASK)) { > - gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK; > - flags &= ~GFP_SLAB_BUG_MASK; > - pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x > (%pGg). Fix your code!\n", > - invalid_mask, &invalid_mask, flags, &flags); > - dump_stack(); > - } > + flags = fixup_gfp_flags(s, flags); > > return allocate_slab(s, > flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node); > -- > 2.11.0
-- Michal Hocko SUSE Labs
