[PATCH v2 2/4] cgroup/cpuset: update some comments about the page allocator

[Brendan Jackman <jackmanb@google.com>]

These comments describing the page allocator are out of date:

- __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It may be out of date for other reasons too but this patch is just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- Completely drop out-of-date details of that function's internal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@nvidia.com>
Link: https://lore.kernel.org/all/DJP11T5V7BDW.2FZZZ8R6LOY4I@nvidia.com/
Signed-off-by: Brendan Jackman <jackmanb@google.com>
---
 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().
  */

-- 
2.54.0