kmem/tracing: add kmem name to kmem_cache_alloc tracepoint

JIRA: https://issues.redhat.com/browse/RHEL-124143

This patch is a backport of the following upstream commit:
commit dfd04ad
Author: Wander Lairson Costa <wander@redhat.com>
Date:   Mon Aug 25 09:59:26 2025 -0300

    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/20250825125927.59816-1-wander@redhat.com
    Signed-off-by: Wander Lairson Costa <wander@redhat.com>
    Cc: David Hildenbrand <david@redhat.com>
    Cc: David Rientjes <rientjes@google.com>
    Cc: Martin Liu <liumartin@google.com>
    Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
    Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Cc: Zi Yan <ziy@nvidia.com>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Charles Haithcock <chaithco@redhat.com>

Author: chaithco

include/trace/events/kmem.h

@@ -22,6 +22,7 @@ TRACE_EVENT(kmem_cache_alloc,
 	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	)
@@ -32,6 +33,7 @@ TRACE_EVENT(kmem_cache_alloc,
 	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;
@@ -41,9 +43,10 @@ TRACE_EVENT(kmem_cache_alloc,
 					  (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),