mm/slab_common: drop kmem_alloc & avoid dereferencing fields when not using

Drop kmem_alloc event class, and define kmalloc and kmem_cache_alloc
using TRACE_EVENT() macro.

And then this patch does:
   - Do not pass pointer to struct kmem_cache to trace_kmalloc.
     gfp flag is enough to know if it's accounted or not.
   - Avoid dereferencing s->object_size and s->size when not using kmem_cache_alloc event.
   - Avoid dereferencing s->name in when not using kmem_cache_free event.
   - Adjust s->size to SLOB_UNITS(s->size) * SLOB_UNIT in SLOB

Cc: Vasily Averin <vasily.averin@linux.dev>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

include/trace/events/kmem.h

@@ -9,17 +9,15 @@
 #include <linux/tracepoint.h>
 #include <trace/events/mmflags.h>
 
-DECLARE_EVENT_CLASS(kmem_alloc,
+TRACE_EVENT(kmem_cache_alloc,
 
 	TP_PROTO(unsigned long call_site,
 		 const void *ptr,
 		 struct kmem_cache *s,
-		 size_t bytes_req,
-		 size_t bytes_alloc,
 		 gfp_t gfp_flags,
 		 int node),
 
-	TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags, node),
+	TP_ARGS(call_site, ptr, s, gfp_flags, node),
 
 	TP_STRUCT__entry(
 		__field(	unsigned long,	call_site	)
@@ -34,13 +32,13 @@ DECLARE_EVENT_CLASS(kmem_alloc,
 	TP_fast_assign(
 		__entry->call_site	= call_site;
 		__entry->ptr		= ptr;
-		__entry->bytes_req	= bytes_req;
-		__entry->bytes_alloc	= bytes_alloc;
+		__entry->bytes_req	= s->object_size;
+		__entry->bytes_alloc	= s->size;
 		__entry->gfp_flags	= (__force unsigned long)gfp_flags;
 		__entry->node		= node;
 		__entry->accounted	= IS_ENABLED(CONFIG_MEMCG_KMEM) ?
 					  ((gfp_flags & __GFP_ACCOUNT) ||
-					  (s && s->flags & SLAB_ACCOUNT)) : false;
+					  (s->flags & SLAB_ACCOUNT)) : false;
 	),
 
 	TP_printk("call_site=%pS ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s node=%d accounted=%s",
@@ -53,22 +51,44 @@ DECLARE_EVENT_CLASS(kmem_alloc,
 		__entry->accounted ? "true" : "false")
 );
 
-DEFINE_EVENT(kmem_alloc, kmalloc,
+TRACE_EVENT(kmalloc,
 
-	TP_PROTO(unsigned long call_site, const void *ptr,
-		 struct kmem_cache *s, size_t bytes_req, size_t bytes_alloc,
-		 gfp_t gfp_flags, int node),
+	TP_PROTO(unsigned long call_site,
+		 const void *ptr,
+		 size_t bytes_req,
+		 size_t bytes_alloc,
+		 gfp_t gfp_flags,
+		 int node),
 
-	TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags, node)
-);
+	TP_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags, node),
 
-DEFINE_EVENT(kmem_alloc, kmem_cache_alloc,
+	TP_STRUCT__entry(
+		__field(	unsigned long,	call_site	)
+		__field(	const void *,	ptr		)
+		__field(	size_t,		bytes_req	)
+		__field(	size_t,		bytes_alloc	)
+		__field(	unsigned long,	gfp_flags	)
+		__field(	int,		node		)
+	),
 
-	TP_PROTO(unsigned long call_site, const void *ptr,
-		 struct kmem_cache *s, size_t bytes_req, size_t bytes_alloc,
-		 gfp_t gfp_flags, int node),
+	TP_fast_assign(
+		__entry->call_site	= call_site;
+		__entry->ptr		= ptr;
+		__entry->bytes_req	= bytes_req;
+		__entry->bytes_alloc	= bytes_alloc;
+		__entry->gfp_flags	= (__force unsigned long)gfp_flags;
+		__entry->node		= node;
+	),
 
-	TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags, node)
+	TP_printk("call_site=%pS ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s node=%d accounted=%s",
+		(void *)__entry->call_site,
+		__entry->ptr,
+		__entry->bytes_req,
+		__entry->bytes_alloc,
+		show_gfp_flags(__entry->gfp_flags),
+		__entry->node,
+		(IS_ENABLED(CONFIG_MEMCG_KMEM) &&
+		 (__entry->gfp_flags & (__force unsigned long)__GFP_ACCOUNT)) ? "true" : "false")
 );
 
 TRACE_EVENT(kfree,
@@ -93,20 +113,20 @@ TRACE_EVENT(kfree,
 
 TRACE_EVENT(kmem_cache_free,
 
-	TP_PROTO(unsigned long call_site, const void *ptr, const char *name),
+	TP_PROTO(unsigned long call_site, const void *ptr, const struct kmem_cache *s),
 
-	TP_ARGS(call_site, ptr, name),
+	TP_ARGS(call_site, ptr, s),
 
 	TP_STRUCT__entry(
 		__field(	unsigned long,	call_site	)
 		__field(	const void *,	ptr		)
-		__string(	name,	name	)
+		__string(	name,		s->name		)
 	),
 
 	TP_fast_assign(
 		__entry->call_site	= call_site;
 		__entry->ptr		= ptr;
-		__assign_str(name, name);
+		__assign_str(name, s->name);
 	),
 
 	TP_printk("call_site=%pS ptr=%p name=%s",

mm/slab.c

@@ -3440,8 +3440,7 @@ void *__kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru,
 {
 	void *ret = slab_alloc(cachep, lru, flags, cachep->object_size, _RET_IP_);
 
-	trace_kmem_cache_alloc(_RET_IP_, ret, cachep, cachep->object_size,
-			       cachep->size, flags, NUMA_NO_NODE);
+	trace_kmem_cache_alloc(_RET_IP_, ret, cachep, flags, NUMA_NO_NODE);
 
 	return ret;
 }
@@ -3536,8 +3535,7 @@ void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
 {
 	void *ret = slab_alloc_node(cachep, NULL, flags, nodeid, cachep->object_size, _RET_IP_);
 
-	trace_kmem_cache_alloc(_RET_IP_, ret, cachep, cachep->object_size,
-			       cachep->size, flags, nodeid);
+	trace_kmem_cache_alloc(_RET_IP_, ret, cachep, flags, nodeid);
 
 	return ret;
 }
@@ -3607,7 +3605,7 @@ void kmem_cache_free(struct kmem_cache *cachep, void *objp)
 	if (!cachep)
 		return;
 
-	trace_kmem_cache_free(_RET_IP_, objp, cachep->name);
+	trace_kmem_cache_free(_RET_IP_, objp, cachep);
 	__do_kmem_cache_free(cachep, objp, _RET_IP_);
 }
 EXPORT_SYMBOL(kmem_cache_free);

mm/slab_common.c

@@ -907,7 +907,7 @@ void *__do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller
 
 	if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
 		ret = __kmalloc_large_node(size, flags, node);
-		trace_kmalloc(_RET_IP_, ret, NULL, size,
+		trace_kmalloc(_RET_IP_, ret, size,
 			      PAGE_SIZE << get_order(size), flags, node);
 		return ret;
 	}
@@ -919,7 +919,7 @@ void *__do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller
 
 	ret = __kmem_cache_alloc_node(s, flags, node, size, caller);
 	ret = kasan_kmalloc(s, ret, size, flags);
-	trace_kmalloc(_RET_IP_, ret, s, size, s->size, flags, node);
+	trace_kmalloc(_RET_IP_, ret, size, s->size, flags, node);
 	return ret;
 }
 
@@ -1005,7 +1005,7 @@ void *kmalloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
 	void *ret = __kmem_cache_alloc_node(s, gfpflags, NUMA_NO_NODE,
 					    size, _RET_IP_);
 
-	trace_kmalloc(_RET_IP_, ret, s, size, s->size, gfpflags, NUMA_NO_NODE);
+	trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, NUMA_NO_NODE);
 
 	ret = kasan_kmalloc(s, ret, size, gfpflags);
 	return ret;
@@ -1017,7 +1017,7 @@ void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
 {
 	void *ret = __kmem_cache_alloc_node(s, gfpflags, node, size, _RET_IP_);
 
-	trace_kmalloc(_RET_IP_, ret, s, size, s->size, gfpflags, node);
+	trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, node);
 
 	ret = kasan_kmalloc(s, ret, size, gfpflags);
 	return ret;
@@ -1072,8 +1072,8 @@ void *kmalloc_large(size_t size, gfp_t flags)
 {
 	void *ret = __kmalloc_large_node(size, flags, NUMA_NO_NODE);
 
-	trace_kmalloc(_RET_IP_, ret, NULL, size,
-		      PAGE_SIZE << get_order(size), flags, NUMA_NO_NODE);
+	trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
+		      flags, NUMA_NO_NODE);
 	return ret;
 }
 EXPORT_SYMBOL(kmalloc_large);
@@ -1082,8 +1082,8 @@ void *kmalloc_large_node(size_t size, gfp_t flags, int node)
 {
 	void *ret = __kmalloc_large_node(size, flags, node);
 
-	trace_kmalloc(_RET_IP_, ret, NULL, size,
-		      PAGE_SIZE << get_order(size), flags, node);
+	trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
+		      flags, node);
 	return ret;
 }
 EXPORT_SYMBOL(kmalloc_large_node);

mm/slob.c

@@ -507,8 +507,7 @@ __do_kmalloc_node(size_t size, gfp_t gfp, int node, unsigned long caller)
 		*m = size;
 		ret = (void *)m + minalign;
 
-		trace_kmalloc(caller, ret, NULL, size,
-			      size + minalign, gfp, node);
+		trace_kmalloc(caller, ret, size, size + minalign, gfp, node);
 	} else {
 		unsigned int order = get_order(size);
 
@@ -516,8 +515,7 @@ __do_kmalloc_node(size_t size, gfp_t gfp, int node, unsigned long caller)
 			gfp |= __GFP_COMP;
 		ret = slob_new_pages(gfp, order, node);
 
-		trace_kmalloc(caller, ret, NULL, size,
-			      PAGE_SIZE << order, gfp, node);
+		trace_kmalloc(caller, ret, size, PAGE_SIZE << order, gfp, node);
 	}
 
 	kmemleak_alloc(ret, size, 1, gfp);
@@ -594,6 +592,9 @@ int __kmem_cache_create(struct kmem_cache *c, slab_flags_t flags)
 		/* leave room for rcu footer at the end of object */
 		c->size += sizeof(struct slob_rcu);
 	}
+
+	/* Actual size allocated */
+	c->size = SLOB_UNITS(c->size) * SLOB_UNIT;
 	c->flags = flags;
 	return 0;
 }
@@ -608,14 +609,10 @@ static void *slob_alloc_node(struct kmem_cache *c, gfp_t flags, int node)
 
 	if (c->size < PAGE_SIZE) {
 		b = slob_alloc(c->size, flags, c->align, node, 0);
-		trace_kmem_cache_alloc(_RET_IP_, b, NULL, c->object_size,
-				       SLOB_UNITS(c->size) * SLOB_UNIT,
-				       flags, node);
+		trace_kmem_cache_alloc(_RET_IP_, b, c, flags, node);
 	} else {
 		b = slob_new_pages(flags, get_order(c->size), node);
-		trace_kmem_cache_alloc(_RET_IP_, b, NULL, c->object_size,
-				       PAGE_SIZE << get_order(c->size),
-				       flags, node);
+		trace_kmem_cache_alloc(_RET_IP_, b, c, flags, node);
 	}
 
 	if (b && c->ctor) {
@@ -671,7 +668,7 @@ static void kmem_rcu_free(struct rcu_head *head)
 void kmem_cache_free(struct kmem_cache *c, void *b)
 {
 	kmemleak_free_recursive(b, c->flags);
-	trace_kmem_cache_free(_RET_IP_, b, c->name);
+	trace_kmem_cache_free(_RET_IP_, b, c);
 	if (unlikely(c->flags & SLAB_TYPESAFE_BY_RCU)) {
 		struct slob_rcu *slob_rcu;
 		slob_rcu = b + (c->size - sizeof(struct slob_rcu));

mm/slub.c

@@ -3243,8 +3243,7 @@ void *__kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
 {
 	void *ret = slab_alloc(s, lru, gfpflags, _RET_IP_, s->object_size);
 
-	trace_kmem_cache_alloc(_RET_IP_, ret, s, s->object_size,
-				s->size, gfpflags, NUMA_NO_NODE);
+	trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, NUMA_NO_NODE);
 
 	return ret;
 }
@@ -3274,8 +3273,7 @@ void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
 {
 	void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, s->object_size);
 
-	trace_kmem_cache_alloc(_RET_IP_, ret, s, s->object_size,
-			       s->size, gfpflags, node);
+	trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, node);
 
 	return ret;
 }
@@ -3517,7 +3515,7 @@ void kmem_cache_free(struct kmem_cache *s, void *x)
 	s = cache_from_obj(s, x);
 	if (!s)
 		return;
-	trace_kmem_cache_free(_RET_IP_, x, s->name);
+	trace_kmem_cache_free(_RET_IP_, x, s);
 	slab_free(s, virt_to_slab(x), x, NULL, &x, 1, _RET_IP_);
 }
 EXPORT_SYMBOL(kmem_cache_free);