cpuset: rename cpuset_node_allowed to cpuset_current_node_allowed

Patch series "vmscan: enforce mems_effective during demotion", v5.

Change reclaim to respect cpuset.mems_effective during demotion when
possible.  Presently, reclaim explicitly ignores cpuset.mems_effective
when demoting, which may cause the cpuset settings to violated.

Implement cpuset_node_allowed() to check the cpuset.mems_effective
associated wih the mem_cgroup of the lruvec being scanned.  This only
applies to cgroup/cpuset v2, as cpuset exists in a different hierarchy
than mem_cgroup in v1.

This requires renaming the existing cpuset_node_allowed() to be
cpuset_current_now_allowed() - which is more descriptive anyway - to
implement the new cpuset_node_allowed() which takes a target cgroup.

This patch (of 2):

Rename cpuset_node_allowed to reflect that the function checks the current
task's cpuset.mems.  This allows us to make a new cpuset_node_allowed
function that checks a target cgroup's cpuset.mems.

Link: https://lkml.kernel.org/r/20250424202806.52632-1-gourry@gourry.net
Link: https://lkml.kernel.org/r/20250424202806.52632-2-gourry@gourry.net
Signed-off-by: Gregory Price <gourry@gourry.net>
Acked-by: Waiman Long <longman@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 5466c96a33dbb905662ddcf064d9c4bd218606f7..d6a4fe5c3b6e2a8b3dffe95fe9ffe8acc7a98380 100644 (file)
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -82,11 +82,11 @@ extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
 void cpuset_init_current_mems_allowed(void);
 int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask);
 
-extern bool cpuset_node_allowed(int node, gfp_t gfp_mask);
+extern bool cpuset_current_node_allowed(int node, gfp_t gfp_mask);
 
 static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
 {
-       return cpuset_node_allowed(zone_to_nid(z), gfp_mask);
+       return cpuset_current_node_allowed(zone_to_nid(z), gfp_mask);
 }
 
 static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 306b60430091452e4ddd263a5aed9aee79ab3417..54f6af362191a1f4ed6f7f58dbada610e153969d 100644 (file)
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -4164,7 +4164,7 @@ static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs)
 }
 
 /*
- * cpuset_node_allowed - Can we allocate on a memory node?
+ * cpuset_current_node_allowed - Can current task allocate on a memory node?
  * @node: is this an allowed node?
  * @gfp_mask: memory allocation flags
  *
@@ -4203,7 +4203,7 @@ static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs)
  *     GFP_KERNEL   - any node in enclosing hardwalled cpuset ok
  *     GFP_USER     - only nodes in current tasks mems allowed ok.
  */
-bool cpuset_node_allowed(int node, gfp_t gfp_mask)
+bool cpuset_current_node_allowed(int node, gfp_t gfp_mask)
 {
        struct cpuset *cs;              /* current cpuset ancestors */
        bool allowed;                   /* is allocation in zone z allowed? */

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 237dcca69e51bf1d2dbe1f11a9f1484f4d5e2573..4ee55edf1ad74768357ffc3d47fa6c8abd8e7839 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3543,7 +3543,7 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
 retry:
        /*
         * Scan zonelist, looking for a zone with enough free.
-        * See also cpuset_node_allowed() comment in kernel/cgroup/cpuset.c.
+        * See also cpuset_current_node_allowed() comment in kernel/cgroup/cpuset.c.
         */
        no_fallback = alloc_flags & ALLOC_NOFRAGMENT;
        z = ac->preferred_zoneref;
@@ -4230,7 +4230,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask, unsigned int order)
                /*
                 * Ignore cpuset mems for non-blocking __GFP_HIGH (probably
                 * GFP_ATOMIC) rather than fail, see the comment for
-                * cpuset_node_allowed().
+                * cpuset_current_node_allowed().
                 */
                if (alloc_flags & ALLOC_MIN_RESERVE)
                        alloc_flags &= ~ALLOC_CPUSET;