[PATCH v3 11/15] mm/slab: pass slab_alloc_context to __do_kmalloc_node()

From: Vlastimil Babka (SUSE)

Date: Mon Jun 15 2026 - 08:00:41 EST


With alloc_flags usage in slab, we can replace __GFP_NO_OBJ_EXT with an
alloc flag that prevents kmalloc recursion. For that we need a version
of kmalloc() that takes alloc_flags and use it in places that perform
these potentially recursive kmalloc allocations (of sheaves or obj_ext
arrays).

As a preparatory step, make __do_kmalloc_node() take a pointer to
slab_alloc_context. This replaces the 'size' and 'caller' parameters and
includes alloc_flags which we'll make use of.

Link: https://patch.msgid.link/20260610-slab_alloc_flags-v2-12-7190909db118@xxxxxxxxxx
Reviewed-by: Hao Li <hao.li@xxxxxxxxx>
Signed-off-by: Vlastimil Babka (SUSE) <vbabka@xxxxxxxxxx>
---
mm/slub.c | 54 ++++++++++++++++++++++++++++++++++++------------------
1 file changed, 36 insertions(+), 18 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 81938774098b..537ea68f417b 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5335,20 +5335,16 @@ void *__kmalloc_large_node_noprof(size_t size, gfp_t flags, int node)
EXPORT_SYMBOL(__kmalloc_large_node_noprof);

static __always_inline
-void *__do_kmalloc_node(size_t size, kmem_buckets *b, gfp_t flags, int node,
- unsigned long caller, kmalloc_token_t token)
+void *__do_kmalloc_node(kmem_buckets *b, gfp_t flags, int node,
+ kmalloc_token_t token, const struct slab_alloc_context *ac)
{
+ const size_t size = ac->orig_size;
struct kmem_cache *s;
void *ret;
- const struct slab_alloc_context ac = {
- .caller_addr = caller,
- .orig_size = size,
- .alloc_flags = SLAB_ALLOC_DEFAULT,
- };

if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
ret = __kmalloc_large_node_noprof(size, flags, node);
- trace_kmalloc(caller, ret, size,
+ trace_kmalloc(ac->caller_addr, ret, size,
PAGE_SIZE << get_order(size), flags, node);
return ret;
}
@@ -5358,22 +5354,34 @@ void *__do_kmalloc_node(size_t size, kmem_buckets *b, gfp_t flags, int node,

s = kmalloc_slab(size, b, flags, token);

- ret = slab_alloc_node(s, flags, node, &ac);
+ ret = slab_alloc_node(s, flags, node, ac);
ret = kasan_kmalloc(s, ret, size, flags);
- trace_kmalloc(caller, ret, size, s->size, flags, node);
+ trace_kmalloc(ac->caller_addr, ret, size, s->size, flags, node);
return ret;
}
void *__kmalloc_node_noprof(DECL_KMALLOC_PARAMS(size, b, token), gfp_t flags, int node)
{
- return __do_kmalloc_node(size, PASS_BUCKET_PARAM(b), flags, node,
- _RET_IP_, PASS_TOKEN_PARAM(token));
+ const struct slab_alloc_context ac = {
+ .caller_addr = _RET_IP_,
+ .orig_size = size,
+ .alloc_flags = SLAB_ALLOC_DEFAULT,
+ };
+
+ return __do_kmalloc_node(PASS_BUCKET_PARAM(b), flags, node,
+ PASS_TOKEN_PARAM(token), &ac);
}
EXPORT_SYMBOL(__kmalloc_node_noprof);

void *__kmalloc_noprof(DECL_TOKEN_PARAMS(size, token), gfp_t flags)
{
- return __do_kmalloc_node(size, NULL, flags, NUMA_NO_NODE, _RET_IP_,
- PASS_TOKEN_PARAM(token));
+ const struct slab_alloc_context ac = {
+ .caller_addr = _RET_IP_,
+ .orig_size = size,
+ .alloc_flags = SLAB_ALLOC_DEFAULT,
+ };
+
+ return __do_kmalloc_node(NULL, flags, NUMA_NO_NODE,
+ PASS_TOKEN_PARAM(token), &ac);
}
EXPORT_SYMBOL(__kmalloc_noprof);

@@ -5468,9 +5476,14 @@ EXPORT_SYMBOL_GPL(_kmalloc_nolock_noprof);
void *__kmalloc_node_track_caller_noprof(DECL_KMALLOC_PARAMS(size, b, token), gfp_t flags,
int node, unsigned long caller)
{
- return __do_kmalloc_node(size, PASS_BUCKET_PARAM(b), flags, node,
- caller, PASS_TOKEN_PARAM(token));
+ const struct slab_alloc_context ac = {
+ .caller_addr = caller,
+ .orig_size = size,
+ .alloc_flags = SLAB_ALLOC_DEFAULT,
+ };

+ return __do_kmalloc_node(PASS_BUCKET_PARAM(b), flags, node,
+ PASS_TOKEN_PARAM(token), &ac);
}
EXPORT_SYMBOL(__kmalloc_node_track_caller_noprof);

@@ -6871,14 +6884,19 @@ void *__kvmalloc_node_noprof(DECL_KMALLOC_PARAMS(size, b, token), unsigned long
{
bool allow_block;
void *ret;
+ const struct slab_alloc_context ac = {
+ .caller_addr = _RET_IP_,
+ .orig_size = size,
+ .alloc_flags = SLAB_ALLOC_DEFAULT,
+ };

/*
* It doesn't really make sense to fallback to vmalloc for sub page
* requests
*/
- ret = __do_kmalloc_node(size, PASS_BUCKET_PARAM(b),
+ ret = __do_kmalloc_node(PASS_BUCKET_PARAM(b),
kmalloc_gfp_adjust(flags, size),
- node, _RET_IP_, PASS_TOKEN_PARAM(token));
+ node, PASS_TOKEN_PARAM(token), &ac);
if (ret || size <= PAGE_SIZE)
return ret;


--
2.54.0