FAILED: patch "[PATCH] mm: memcg/slab: fix obj_cgroup_charge() return value handling" failed to apply to 5.9-stable tree

PATCH [email protected] 2 participants 3 messages Dec 9, 2020 – Dec 10, 2020

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Stable branch Memory management Slab allocator

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[email protected]

author maintainer

2020-12-09 15:57 UTC #0 lore raw

The patch below does not apply to the 5.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From becaba65f62f88e553ec92ed98370e9d2b18e629 Mon Sep 17 00:00:00 2001
From: Roman Gushchin <[email protected]>
Date: Sat, 5 Dec 2020 22:14:45 -0800
Subject: [PATCH] mm: memcg/slab: fix obj_cgroup_charge() return value handling

Commit 10befea91b61 ("mm: memcg/slab: use a single set of kmem_caches for all allocations") introduced a regression into the handling of the obj_cgroup_charge() return value. If a non-zero value is returned (indicating of exceeding one of memory.max limits), the allocation should fail, instead of falling back to non-accounted mode.

To make the code more readable, move memcg_slab_pre_alloc_hook() and memcg_slab_post_alloc_hook() calling conditions into bodies of these hooks.

Fixes 10befea91b61 ("mm: memcg/slab: use a single set of kmem_caches for all allocations")

Signed-off-by Roman Gushchin <[email protected]>

Signed-off-by Andrew Morton <[email protected]>

Reviewed-by Shakeel Butt <[email protected]>

Cc Johannes Weiner <[email protected]>

Cc Michal Hocko <[email protected]>

Cc <[email protected]>

Link https://lkml.kernel.org/r/[email protected] open here

Signed-off-by Linus Torvalds <[email protected]>

mm/slab.h +24 ~~-16~~

index 6d7c6a5056ba..f9977d6613d6 100644
@@ -274,22 +274,32 @@ static inline size_t obj_full_size(struct kmem_cache *s)
 	return s->size + sizeof(struct obj_cgroup *);
 }
 
-static inline struct obj_cgroup *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
-							   size_t objects,
-							   gfp_t flags)
+/*
+ * Returns false if the allocation should fail.
+ */
+static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
+					     struct obj_cgroup **objcgp,
+					     size_t objects, gfp_t flags)
 {
 	struct obj_cgroup *objcg;
 
+	if (!memcg_kmem_enabled())
+		return true;
+
+	if (!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT))
+		return true;
+
 	objcg = get_obj_cgroup_from_current();
 	if (!objcg)
-		return NULL;
+		return true;
 
 	if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s))) {
 		obj_cgroup_put(objcg);
-		return NULL;
+		return false;
 	}
 
-	return objcg;
+	*objcgp = objcg;
+	return true;
 }
 
 static inline void mod_objcg_state(struct obj_cgroup *objcg,

@@ -315,7 +325,7 @@ static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
 	unsigned long off;
 	size_t i;
 
-	if (!objcg)
+	if (!memcg_kmem_enabled() || !objcg)
 		return;
 
 	flags &= ~__GFP_ACCOUNT;

@@ -400,11 +410,11 @@ static inline void memcg_free_page_obj_cgroups(struct page *page)
 {
 }
 
-static inline struct obj_cgroup *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
-							   size_t objects,
-							   gfp_t flags)
+static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
+					     struct obj_cgroup **objcgp,
+					     size_t objects, gfp_t flags)
 {
-	return NULL;
+	return true;
 }
 
 static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,

@@ -508,9 +518,8 @@ static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
 	if (should_failslab(s, flags))
 		return NULL;
 
-	if (memcg_kmem_enabled() &&
-	    ((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT)))
-		*objcgp = memcg_slab_pre_alloc_hook(s, size, flags);
+	if (!memcg_slab_pre_alloc_hook(s, objcgp, size, flags))
+		return NULL;
 
 	return s;
 }

@@ -529,8 +538,7 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s,
 					 s->flags, flags);
 	}
 
-	if (memcg_kmem_enabled())
-		memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
+	memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
 }
 
 #ifndef CONFIG_SLOB

Roman Gushchin

Reviewed-by Shakeel Butt

2020-12-09 21:31 UTC #1 lore raw

Quoted 5 lines · Greg Kroah-Hartman

The patch below does not apply to the 5.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Hi Greg!

Please, find the backport below.

Thanks!

--------------------------------------------------------------------------------

From 838b473ad8fdba90afb2ec8220eb100bf73675d6 Mon Sep 17 00:00:00 2001
From: Roman Gushchin <[email protected]>
Date: Sat, 5 Dec 2020 22:14:45 -0800
Subject: [PATCH] mm: memcg/slab: fix obj_cgroup_charge() return value handling

To make the code more readable, move memcg_slab_pre_alloc_hook() and memcg_slab_post_alloc_hook() calling conditions into bodies of these hooks.

Fixes 10befea91b61 ("mm: memcg/slab: use a single set of kmem_caches for all allocations")

Signed-off-by Roman Gushchin <[email protected]>

Signed-off-by Andrew Morton <[email protected]>

Reviewed-by Shakeel Butt <[email protected]>

Cc Johannes Weiner <[email protected]>

Cc Michal Hocko <[email protected]>

Cc <[email protected]>

Link https://lkml.kernel.org/r/[email protected] open here

Signed-off-by Linus Torvalds <[email protected]>

(cherry picked from commit becaba65f62f88e553ec92ed98370e9d2b18e629)

---
 mm/slab.h | 42 +++++++++++++++++++++++++-----------------
 1 file changed, 25 insertions(+), 17 deletions(-)

mm/slab.h +25 ~~-17~~

index 6dd4b702888a..70aa1b5903fc 100644
@@ -275,25 +275,35 @@ static inline size_t obj_full_size(struct kmem_cache *s)
 	return s->size + sizeof(struct obj_cgroup *);
 }
 
-static inline struct obj_cgroup *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
-							   size_t objects,
-							   gfp_t flags)
+/*
+ * Returns false if the allocation should fail.
+ */
+static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
+					     struct obj_cgroup **objcgp,
+					     size_t objects, gfp_t flags)
 {
 	struct obj_cgroup *objcg;
 
+	if (!memcg_kmem_enabled())
+		return true;
+
+	if (!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT))
+		return true;
+
 	if (memcg_kmem_bypass())
-		return NULL;
+		return true;
 
 	objcg = get_obj_cgroup_from_current();
 	if (!objcg)
-		return NULL;
+		return true;
 
 	if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s))) {
 		obj_cgroup_put(objcg);
-		return NULL;
+		return false;
 	}
 
-	return objcg;
+	*objcgp = objcg;
+	return true;
 }
 
 static inline void mod_objcg_state(struct obj_cgroup *objcg,

@@ -319,7 +329,7 @@ static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
 	unsigned long off;
 	size_t i;
 
-	if (!objcg)
+	if (!memcg_kmem_enabled() || !objcg)
 		return;
 
 	flags &= ~__GFP_ACCOUNT;

@@ -404,11 +414,11 @@ static inline void memcg_free_page_obj_cgroups(struct page *page)
 {
 }
 
-static inline struct obj_cgroup *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
-							   size_t objects,
-							   gfp_t flags)
+static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
+					     struct obj_cgroup **objcgp,
+					     size_t objects, gfp_t flags)
 {
-	return NULL;
+	return true;
 }
 
 static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,

@@ -512,9 +522,8 @@ static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
 	if (should_failslab(s, flags))
 		return NULL;
 
-	if (memcg_kmem_enabled() &&
-	    ((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT)))
-		*objcgp = memcg_slab_pre_alloc_hook(s, size, flags);
+	if (!memcg_slab_pre_alloc_hook(s, objcgp, size, flags))
+		return NULL;
 
 	return s;
 }

@@ -533,8 +542,7 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s,
 					 s->flags, flags);
 	}
 
-	if (memcg_kmem_enabled())
-		memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
+	memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
 }
 
 #ifndef CONFIG_SLOB

Signature · 1 line

2.26.2

Greg KH

author maintainer

2020-12-10 12:46 UTC #2 lore raw

Quoted 10 lines · Roman Gushchin

Quoted 5 lines · Greg Kroah-Hartman
The patch below does not apply to the 5.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
Hi Greg!
Please, find the backport below.

Now queued up, thanks!

greg k-h