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>

1 files changed, 8 insertions, 11 deletions

diff --git a/mm/slob.c b/mm/slob.c
index 3208c56d8f82..771af84576bf 100644
--- a/mm/slob.c
+++ b/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));