Re: [PATCH v3 2/4] cgroup/cpuset: update some comments about the page allocator
From: Waiman Long
Date: Fri Jul 17 2026 - 11:10:09 EST
On 7/15/26 7:03 AM, Brendan Jackman wrote:
These comments describing the page allocator are out of date:Acked-by: Waiman Long <longman@xxxxxxxxxx>
- __alloc_pages() is no longer a public API and has no business being
described outside of mm/.
- The `wait` variable is gone.
It may be out of date for other reasons too but this patch is just
fixing the issues that stood out.
To fix it:
- Instead of referring to a specific function, instead to "the page
allocator"
- Completely drop out-of-date details of that function's internal
behaviour, since they were irrelevant anyway.
Suggested-by: Zi Yan <ziy@xxxxxxxxxx>
Link: https://lore.kernel.org/all/DJP11T5V7BDW.2FZZZ8R6LOY4I@xxxxxxxxxx/
Reviewed-by: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Brendan Jackman <jackmanb@xxxxxxxxxx>
---
kernel/cgroup/cpuset.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 24ea2d09cdbdb..dfd0f827e3b92 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -4193,7 +4193,7 @@ static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs)
* nearest enclosing hardwalled ancestor cpuset.
*
* Scanning up parent cpusets requires callback_lock. The
- * __alloc_pages() routine only calls here with __GFP_HARDWALL bit
+ * page allocator only calls here with __GFP_HARDWALL bit
* _not_ set if it's a GFP_KERNEL allocation, and all nodes in the
* current tasks mems_allowed came up empty on the first pass over
* the zonelist. So only GFP_KERNEL allocations, if all nodes in the
@@ -4206,11 +4206,8 @@ static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs)
* come before the __GFP_HARDWALL check, otherwise a dying task
* would be blocked on the fast path.
*
- * The second pass through get_page_from_freelist() doesn't even call
- * here for GFP_ATOMIC calls. For those calls, the __alloc_pages()
- * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set
- * in alloc_flags. That logic and the checks below have the combined
- * affect that:
+ * The second pass through get_page_from_freelist() doesn't even call here for
+ * GFP_ATOMIC calls. That, and the checks below have the combined affect that:
* in_interrupt - any node ok (current task context irrelevant)
* GFP_ATOMIC - any node ok
* tsk_is_oom_victim - any node ok
@@ -4327,8 +4324,8 @@ void cpuset_nodes_allowed(struct cgroup *cgroup, nodemask_t *mask)
* should not be possible for the following code to return an
* offline node. But if it did, that would be ok, as this routine
* is not returning the node where the allocation must be, only
- * the node where the search should start. The zonelist passed to
- * __alloc_pages() will include all nodes. If the slab allocator
+ * the node where the search should start. The zonelist used by
+ * the allocator will include all nodes. If the slab allocator
* is passed an offline node, it will fall back to the local node.
* See kmem_cache_alloc_node().
*/