kmem/tracing: add kmem name to kmem_cache_alloc tracepoint

The kmem_cache_free tracepoint includes a "name" field, which allows for
easy identification and filtering of specific kmem's. However, the
kmem_cache_alloc tracepoint lacks this field, making it difficult to pair
corresponding alloc and free events for analysis.

Add the "name" field to kmem_cache_alloc to enable consistent tracking and
correlation of kmem alloc and free events.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Wander Lairson Costa <[e-mail]>
Cc: David Hildenbrand <[e-mail]>
Cc: David Rientjes <[e-mail]>
Cc: Martin Liu <[e-mail]>
Cc: "Masami Hiramatsu (Google)" <[e-mail]>
Cc: Mathieu Desnoyers <[e-mail]>
Cc: Steven Rostedt <[e-mail]>
Cc: Zi Yan <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

include/trace/events/kmem.h

···
 	TP_STRUCT__entry(
 		__field(	unsigned long,	call_site	)
 		__field(	const void *,	ptr		)
+		__string(	name,		s->name		)
 		__field(	size_t,		bytes_req	)
 		__field(	size_t,		bytes_alloc	)
 		__field(	unsigned long,	gfp_flags	)
···
 	TP_fast_assign(
 		__entry->call_site	= call_site;
 		__entry->ptr		= ptr;
+		__assign_str(name);
 		__entry->bytes_req	= s->object_size;
 		__entry->bytes_alloc	= s->size;
 		__entry->gfp_flags	= (__force unsigned long)gfp_flags;
···
 					  (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",
+	TP_printk("call_site=%pS ptr=%p name=%s bytes_req=%zu bytes_alloc=%zu gfp_flags=%s node=%d accounted=%s",
 		(void *)__entry->call_site,
 		__entry->ptr,
+		__get_str(name),
 		__entry->bytes_req,
 		__entry->bytes_alloc,
 		show_gfp_flags(__entry->gfp_flags),