From 8f4fc071b1926d0b20336e2b3f8ab85c94c734c5 Mon Sep 17 00:00:00 2001 From: Vladimir Davydov Date: Thu, 14 May 2015 15:16:55 -0700 Subject: gfp: add __GFP_NOACCOUNT Not all kmem allocations should be accounted to memcg. The following patch gives an example when accounting of a certain type of allocations to memcg can effectively result in a memory leak. This patch adds the __GFP_NOACCOUNT flag which if passed to kmalloc and friends will force the allocation to go through the root cgroup. It will be used by the next patch. Note, since in case of kmemleak enabled each kmalloc implies yet another allocation from the kmemleak_object cache, we add __GFP_NOACCOUNT to gfp_kmemleak_mask. Alternatively, we could introduce a per kmem cache flag disabling accounting for all allocations of a particular kind, but (a) we would not be able to bypass accounting for kmalloc then and (b) a kmem cache with this flag set could not be merged with a kmem cache without this flag, which would increase the number of global caches and therefore fragmentation even if the memory cgroup controller is not used. Despite its generic name, currently __GFP_NOACCOUNT disables accounting only for kmem allocations while user page allocations are always charged. To catch abusing of this flag, a warning is issued on an attempt of passing it to mem_cgroup_try_charge. Signed-off-by: Vladimir Davydov Cc: Tejun Heo Cc: Johannes Weiner Cc: Michal Hocko Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Greg Thelen Cc: Greg Kroah-Hartman Cc: [4.0.x] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/gfp.h | 2 ++ include/linux/memcontrol.h | 4 ++++ 2 files changed, 6 insertions(+) (limited to 'include/linux') diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 97a9373e61e8..15928f0647e4 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -30,6 +30,7 @@ struct vm_area_struct; #define ___GFP_HARDWALL 0x20000u #define ___GFP_THISNODE 0x40000u #define ___GFP_RECLAIMABLE 0x80000u +#define ___GFP_NOACCOUNT 0x100000u #define ___GFP_NOTRACK 0x200000u #define ___GFP_NO_KSWAPD 0x400000u #define ___GFP_OTHER_NODE 0x800000u @@ -87,6 +88,7 @@ struct vm_area_struct; #define __GFP_HARDWALL ((__force gfp_t)___GFP_HARDWALL) /* Enforce hardwall cpuset memory allocs */ #define __GFP_THISNODE ((__force gfp_t)___GFP_THISNODE)/* No fallback, no policies */ #define __GFP_RECLAIMABLE ((__force gfp_t)___GFP_RECLAIMABLE) /* Page is reclaimable */ +#define __GFP_NOACCOUNT ((__force gfp_t)___GFP_NOACCOUNT) /* Don't account to kmemcg */ #define __GFP_NOTRACK ((__force gfp_t)___GFP_NOTRACK) /* Don't track with kmemcheck */ #define __GFP_NO_KSWAPD ((__force gfp_t)___GFP_NO_KSWAPD) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 72dff5fb0d0c..6c8918114804 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -463,6 +463,8 @@ memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg, int order) if (!memcg_kmem_enabled()) return true; + if (gfp & __GFP_NOACCOUNT) + return true; /* * __GFP_NOFAIL allocations will move on even if charging is not * possible. Therefore we don't even try, and have this allocation @@ -522,6 +524,8 @@ memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp) { if (!memcg_kmem_enabled()) return cachep; + if (gfp & __GFP_NOACCOUNT) + return cachep; if (gfp & __GFP_NOFAIL) return cachep; if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD)) -- cgit v1.2.3 From 929aa5b250bfc59aca492d3213c7f3a53e2a5247 Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Thu, 14 May 2015 15:17:01 -0700 Subject: uidgid: make uid_valid and gid_valid work with !CONFIG_MULTIUSER {u,g}id_valid call {u,g}id_eq, which calls __k{u,g}id_val on both arguments and compares. With !CONFIG_MULTIUSER, __k{u,g}id_val return a constant 0, which makes {u,g}id_valid always return false. Change {u,g}id_valid to compare their argument against -1 instead. That produces identical results in the normal CONFIG_MULTIUSER=y case, but with !CONFIG_MULTIUSER will make {u,g}id_valid constant-fold into "return true;" rather than "return false;". This fixes uses of devpts without CONFIG_MULTIUSER. Signed-off-by: Josh Triplett Reported-by: Fengguang Wu , Cc: Peter Hurley Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/uidgid.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/uidgid.h b/include/linux/uidgid.h index 0ee05da38899..03835522dfcb 100644 --- a/include/linux/uidgid.h +++ b/include/linux/uidgid.h @@ -109,12 +109,12 @@ static inline bool gid_lte(kgid_t left, kgid_t right) static inline bool uid_valid(kuid_t uid) { - return !uid_eq(uid, INVALID_UID); + return __kuid_val(uid) != (uid_t) -1; } static inline bool gid_valid(kgid_t gid) { - return !gid_eq(gid, INVALID_GID); + return __kgid_val(gid) != (gid_t) -1; } #ifdef CONFIG_USER_NS -- cgit v1.2.3