[PATCH v2 07/16] mm/slab: replace struct partial_context with slab_alloc_context
From: Vlastimil Babka (SUSE)
Date: Wed Jun 10 2026 - 11:57:00 EST
Refactor get_from_partial_node(), get_from_any_partial(),
get_from_partial() and ___slab_alloc().
Remove struct partial_context, which used to be more substantial but
shrank as part of the sheaves conversion. Instead pass gfp_flags and
pointer to the new slab_alloc_context, which together is a superset of
partial_context.
This means alloc_flags are now available and we can use them to
determine if spinning is allowed, further reducing false positive "not
allowed" in the slow path due to gfp flags lacking __GFP_RECLAIM.
Signed-off-by: Vlastimil Babka (SUSE) <vbabka@xxxxxxxxxx>
---
mm/slub.c | 52 ++++++++++++++++++++++++----------------------------
1 file changed, 24 insertions(+), 28 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index ef745b37d063..98b79e5e7679 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -220,12 +220,6 @@ struct slab_alloc_context {
unsigned int alloc_flags;
};
-/* Structure holding parameters for get_from_partial() call chain */
-struct partial_context {
- gfp_t flags;
- unsigned int orig_size;
-};
-
/* Structure holding parameters for get_partial_node_bulk() */
struct partial_bulk_context {
gfp_t flags;
@@ -3826,7 +3820,8 @@ static bool get_partial_node_bulk(struct kmem_cache *s,
*/
static void *get_from_partial_node(struct kmem_cache *s,
struct kmem_cache_node *n,
- struct partial_context *pc)
+ gfp_t gfp_flags,
+ struct slab_alloc_context *ac)
{
struct slab *slab, *slab2;
unsigned long flags;
@@ -3841,7 +3836,7 @@ static void *get_from_partial_node(struct kmem_cache *s,
if (!n || !n->nr_partial)
return NULL;
- if (gfpflags_allow_spinning(pc->flags))
+ if (alloc_flags_allow_spinning(ac->alloc_flags))
spin_lock_irqsave(&n->list_lock, flags);
else if (!spin_trylock_irqsave(&n->list_lock, flags))
return NULL;
@@ -3849,12 +3844,12 @@ static void *get_from_partial_node(struct kmem_cache *s,
struct freelist_counters old, new;
- if (!pfmemalloc_match(slab, pc->flags))
+ if (!pfmemalloc_match(slab, gfp_flags))
continue;
if (IS_ENABLED(CONFIG_SLUB_TINY) || kmem_cache_debug(s)) {
object = alloc_single_from_partial(s, n, slab,
- pc->orig_size);
+ ac->orig_size);
if (object)
break;
continue;
@@ -3888,15 +3883,16 @@ static void *get_from_partial_node(struct kmem_cache *s,
/*
* Get an object from somewhere. Search in increasing NUMA distances.
*/
-static void *get_from_any_partial(struct kmem_cache *s, struct partial_context *pc)
+static void *get_from_any_partial(struct kmem_cache *s, gfp_t gfp_flags,
+ struct slab_alloc_context *ac)
{
#ifdef CONFIG_NUMA
struct zonelist *zonelist;
struct zoneref *z;
struct zone *zone;
- enum zone_type highest_zoneidx = gfp_zone(pc->flags);
+ enum zone_type highest_zoneidx = gfp_zone(gfp_flags);
unsigned int cpuset_mems_cookie;
- bool allow_spin = gfpflags_allow_spinning(pc->flags);
+ bool allow_spin = alloc_flags_allow_spinning(ac->alloc_flags);
/*
* The defrag ratio allows a configuration of the tradeoffs between
@@ -3930,16 +3926,17 @@ static void *get_from_any_partial(struct kmem_cache *s, struct partial_context *
if (allow_spin)
cpuset_mems_cookie = read_mems_allowed_begin();
- zonelist = node_zonelist(mempolicy_slab_node(), pc->flags);
+ zonelist = node_zonelist(mempolicy_slab_node(), gfp_flags);
for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) {
struct kmem_cache_node *n;
n = get_node(s, zone_to_nid(zone));
- if (n && cpuset_zone_allowed(zone, pc->flags) &&
+ if (n && cpuset_zone_allowed(zone, gfp_flags) &&
n->nr_partial > s->min_partial) {
- void *object = get_from_partial_node(s, n, pc);
+ void *object = get_from_partial_node(s, n,
+ gfp_flags, ac);
if (object) {
/*
@@ -3961,8 +3958,8 @@ static void *get_from_any_partial(struct kmem_cache *s, struct partial_context *
/*
* Get an object from a partial slab
*/
-static void *get_from_partial(struct kmem_cache *s, int node,
- struct partial_context *pc)
+static void *get_from_partial(struct kmem_cache *s, int node, gfp_t flags,
+ struct slab_alloc_context *ac)
{
int searchnode = node;
void *object;
@@ -3970,11 +3967,11 @@ static void *get_from_partial(struct kmem_cache *s, int node,
if (node == NUMA_NO_NODE)
searchnode = numa_mem_id();
- object = get_from_partial_node(s, get_node(s, searchnode), pc);
- if (object || (node != NUMA_NO_NODE && (pc->flags & __GFP_THISNODE)))
+ object = get_from_partial_node(s, get_node(s, searchnode), flags, ac);
+ if (object || (node != NUMA_NO_NODE && (flags & __GFP_THISNODE)))
return object;
- return get_from_any_partial(s, pc);
+ return get_from_any_partial(s, flags, ac);
}
static bool has_pcs_used(int cpu, struct kmem_cache *s)
@@ -4454,16 +4451,16 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
struct slab_alloc_context *ac)
{
bool allow_spin = alloc_flags_allow_spinning(ac->alloc_flags);
+ gfp_t trynode_flags;
void *object;
struct slab *slab;
- struct partial_context pc;
bool try_thisnode = true;
stat(s, ALLOC_SLOWPATH);
new_objects:
- pc.flags = gfpflags;
+ trynode_flags = gfpflags;
/*
* When a preferred node is indicated but no __GFP_THISNODE
*
@@ -4479,17 +4476,16 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
&& try_thisnode)) {
if (unlikely(!allow_spin))
/* Do not upgrade gfp to NOWAIT from more restrictive mode */
- pc.flags = gfpflags | __GFP_THISNODE;
+ trynode_flags = gfpflags | __GFP_THISNODE;
else
- pc.flags = GFP_NOWAIT | __GFP_THISNODE;
+ trynode_flags = GFP_NOWAIT | __GFP_THISNODE;
}
- pc.orig_size = ac->orig_size;
- object = get_from_partial(s, node, &pc);
+ object = get_from_partial(s, node, trynode_flags, ac);
if (object)
goto success;
- slab = new_slab(s, pc.flags, node);
+ slab = new_slab(s, trynode_flags, node);
if (unlikely(!slab)) {
if (node != NUMA_NO_NODE && !(gfpflags & __GFP_THISNODE)
--
2.54.0