On Thu, Jul 28, 2022 at 06:09:27PM +0200, Vlastimil Babka wrote:

On 7/12/22 15:39, Hyeonggon Yoo wrote:

quoted

Now that kmalloc_large_node() is in common code, pass large requests
to page allocator in kmalloc_node() using kmalloc_large_node().

One problem is that currently there is no tracepoint in
kmalloc_large_node(). Instead of simply putting tracepoint in it,
use kmalloc_large_node{,_notrace} depending on its caller to show
useful address for both inlined kmalloc_node() and
__kmalloc_node_track_caller() when large objects are allocated.

Signed-off-by: Hyeonggon Yoo <redacted>

Reviewed-by: Vlastimil Babka <redacted>

Thanks!

Nit below:

quoted

---
 v3:
	This patch is new in v3 and this avoids
	missing caller in __kmalloc_large_node_track_caller()
	when kmalloc_large_node() is called.

 include/linux/slab.h | 26 +++++++++++++++++++-------
 mm/slab.h            |  2 ++
 mm/slab_common.c     | 17 ++++++++++++++++-
 mm/slub.c            |  2 +-
 4 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 082499306098..fd2e129fc813 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h

@@ -571,23 +571,35 @@ static __always_inline __alloc_size(1) void *kmalloc(size_t size, gfp_t flags)
 	return __kmalloc(size, flags);
 }
 
+#ifndef CONFIG_SLOB
 static __always_inline __alloc_size(1) void *kmalloc_node(size_t size, gfp_t flags, int node)
 {
-#ifndef CONFIG_SLOB
-	if (__builtin_constant_p(size) &&
-		size <= KMALLOC_MAX_CACHE_SIZE) {
-		unsigned int i = kmalloc_index(size);
+	if (__builtin_constant_p(size)) {
+		unsigned int index;
 
-		if (!i)
+		if (size > KMALLOC_MAX_CACHE_SIZE)
+			return kmalloc_large_node(size, flags, node);
+
+		index = kmalloc_index(size);
+
+		if (!index)
 			return ZERO_SIZE_PTR;
 
 		return kmem_cache_alloc_node_trace(
-				kmalloc_caches[kmalloc_type(flags)][i],
+				kmalloc_caches[kmalloc_type(flags)][index],
 						flags, node, size);
 	}
-#endif
 	return __kmalloc_node(size, flags, node);
 }
+#else
+static __always_inline __alloc_size(1) void *kmalloc_node(size_t size, gfp_t flags, int node)
+{
+	if (__builtin_constant_p(size) && size > KMALLOC_MAX_CACHE_SIZE)
+		return kmalloc_large_node(size, flags, node);
+
+	return __kmalloc_node(size, flags, node);
+}
+#endif
 
 /**
  * kmalloc_array - allocate memory for an array.

diff --git a/mm/slab.h b/mm/slab.h
index a8d5eb1c323f..7cb51ff44f0c 100644
--- a/mm/slab.h
+++ b/mm/slab.h

@@ -273,6 +273,8 @@ void create_kmalloc_caches(slab_flags_t);
 
 /* Find the kmalloc slab corresponding for a certain size */
 struct kmem_cache *kmalloc_slab(size_t, gfp_t);
+
+void *kmalloc_large_node_notrace(size_t size, gfp_t flags, int node);
 #endif
 
 gfp_t kmalloc_fix_flags(gfp_t flags);

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 6f855587b635..dc872e0ef0fc 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c

@@ -956,7 +956,8 @@ void *kmalloc_large(size_t size, gfp_t flags)
 }
 EXPORT_SYMBOL(kmalloc_large);
 
-void *kmalloc_large_node(size_t size, gfp_t flags, int node)
+static __always_inline

I don't think we need to inline, compiler should be able to make
kmalloc_large_node(_notrace) quite efficient anyway.

You mean s/static __always_inline/static/g, or like this?

kmalloc_large_node_notrace():
	fold __kmalloc_large_node_notrace() into here

kmalloc_large_node():
	kmalloc_large_node_notrace()
	trace_kmalloc()

I have no strong opinion.

IMO It's unlikely that there would be workloads that are
meaningfully affected by inlining or not inlining __kmalloc_large_node_notrace().
Just wanted to avoid adding even tiny of overhead by this series.

quoted

+void *__kmalloc_large_node_notrace(size_t size, gfp_t flags, int node)
 {
 	struct page *page;
 	void *ptr = NULL;

@@ -976,6 +977,20 @@ void *kmalloc_large_node(size_t size, gfp_t flags, int node)
 
 	return ptr;
 }
+
+void *kmalloc_large_node_notrace(size_t size, gfp_t flags, int node)
+{
+	return __kmalloc_large_node_notrace(size, flags, node);
+}
+
+void *kmalloc_large_node(size_t size, gfp_t flags, int node)
+{
+	void *ret = __kmalloc_large_node_notrace(size, flags, node);
+
+	trace_kmalloc_node(_RET_IP_, ret, NULL, size,
+			   PAGE_SIZE << get_order(size), flags, node);
+	return ret;
+}
 EXPORT_SYMBOL(kmalloc_large_node);
 
 #ifdef CONFIG_SLAB_FREELIST_RANDOM

diff --git a/mm/slub.c b/mm/slub.c
index f22a84dd27de..3d02cf44adf7 100644
--- a/mm/slub.c
+++ b/mm/slub.c

@@ -4401,7 +4401,7 @@ void *__do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller
 	void *ret;
 
 	if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
-		ret = kmalloc_large_node(size, flags, node);
+		ret = kmalloc_large_node_notrace(size, flags, node);
 
 		trace_kmalloc_node(caller, ret, NULL,
 				   size, PAGE_SIZE << get_order(size),

-- 
Thanks,
Hyeonggon