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, 42 insertions, 22 deletions

diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h
index e078ebcdc4b1..243073cfc29d 100644
--- a/include/trace/events/kmem.h
+++ b/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",