[PATCH RFC v2 06/18] mm: page_alloc: thread pghint_t through get_page_from_freelist

Michael S. Tsirkin
2026-04-20T12:50:49Z

Add pghint_t *hints to get_page_from_freelist() and pass it to
prep_new_page(). All internal callers except the main fast path
in __alloc_frozen_pages_hints_noprof() pass NULL.

The next patch uses this to return hints from
post_alloc_hook() to callers via __alloc_frozen_pages_hints().

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
mm/page_alloc.c | 37 +++++++++++++++++++++++--------------
1 file changed, 23 insertions(+), 14 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b0971a1eaa73..ece61d02ea96 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2483,7 +2483,8 @@ __rmqueue_steal(struct zone *zone, int order, int start_migratetype)
continue;

page = get_page_from_free_area(area, fallback_mt);
- page_del_and_expand(zone, page, order, current_order, fallback_mt);
+ page_del_and_expand(zone, page, order, current_order,
+ fallback_mt);
trace_mm_page_alloc_extfrag(page, order, current_order,
start_migratetype, fallback_mt);
return page;
@@ -3294,7 +3295,8 @@ struct page *rmqueue_buddy(struct zone *preferred_zone, struct zone *zone,
* high-order atomic allocation in the future.
*/
if (!page && (alloc_flags & (ALLOC_OOM|ALLOC_NON_BLOCK)))
- page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
+ page = __rmqueue_smallest(zone, order,
+ MIGRATE_HIGHATOMIC);

if (!page) {
spin_unlock_irqrestore(&zone->lock, flags);
@@ -3414,7 +3416,8 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone,
*/
pcp->free_count >>= 1;
list = &pcp->lists[order_to_pindex(migratetype, order)];
- page = __rmqueue_pcplist(zone, order, migratetype, alloc_flags, pcp, list);
+ page = __rmqueue_pcplist(zone, order, migratetype, alloc_flags, pcp,
+ list);
pcp_spin_unlock(pcp, UP_flags);
if (page) {
__count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
@@ -3451,7 +3454,7 @@ struct page *rmqueue(struct zone *preferred_zone,
}

page = rmqueue_buddy(preferred_zone, zone, order, alloc_flags,
- migratetype);
+ migratetype);

out:
/* Separate test+clear to avoid unnecessary atomics */
@@ -3835,7 +3838,7 @@ static inline unsigned int gfp_to_alloc_flags_cma(gfp_t gfp_mask,
*/
static struct page *
get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
- const struct alloc_context *ac)
+ const struct alloc_context *ac, pghint_t *hints)
{
struct zoneref *z;
struct zone *zone;
@@ -4084,14 +4087,14 @@ __alloc_pages_cpuset_fallback(gfp_t gfp_mask, unsigned int order,
struct page *page;

page = get_page_from_freelist(gfp_mask, order,
- alloc_flags|ALLOC_CPUSET, ac);
+ alloc_flags|ALLOC_CPUSET, ac, NULL);
/*
* fallback to ignore cpuset restriction if our nodes
* are depleted
*/
if (!page)
page = get_page_from_freelist(gfp_mask, order,
- alloc_flags, ac);
+ alloc_flags, ac, NULL);
return page;
}

@@ -4129,7 +4132,8 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
*/
page = get_page_from_freelist((gfp_mask | __GFP_HARDWALL) &
~__GFP_DIRECT_RECLAIM, order,
- ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac);
+ ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac,
+ NULL);
if (page)
goto out;

@@ -4227,7 +4231,8 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,

/* Try get a page from the freelist if available */
if (!page)
- page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
+ page = get_page_from_freelist(gfp_mask, order, alloc_flags,
+ ac, NULL);

if (page) {
struct zone *zone = page_zone(page);
@@ -4477,7 +4482,8 @@ __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
goto out;

retry:
- page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
+ page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac,
+ NULL);

/*
* If an allocation failed after direct reclaim, it could be because
@@ -4831,7 +4837,8 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
* The adjusted alloc_flags might result in immediate success, so try
* that first
*/
- page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
+ page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac,
+ NULL);
if (page)
goto got_pg;

@@ -5249,7 +5256,7 @@ struct page *__alloc_frozen_pages_hints_noprof(gfp_t gfp, unsigned int order,
struct alloc_context ac = { };

if (hints)
- *hints = (pghint_t)0;
+ *hints = 0;

/*
* There are several places where we assume that the order value is sane
@@ -5279,7 +5286,8 @@ struct page *__alloc_frozen_pages_hints_noprof(gfp_t gfp, unsigned int order,
alloc_flags |= alloc_flags_nofragment(zonelist_zone(ac.preferred_zoneref), gfp);

/* First allocation attempt */
- page = get_page_from_freelist(alloc_gfp, order, alloc_flags, &ac);
+ page = get_page_from_freelist(alloc_gfp, order, alloc_flags, &ac,
+ hints);
if (likely(page))
goto out;

@@ -7855,7 +7863,8 @@ struct page *alloc_frozen_pages_nolock_noprof(gfp_t gfp_flags, int nid, unsigned
* Best effort allocation from percpu free list.
* If it's empty attempt to spin_trylock zone->lock.
*/
- page = get_page_from_freelist(alloc_gfp, order, alloc_flags, &ac);
+ page = get_page_from_freelist(alloc_gfp, order, alloc_flags, &ac,
+ NULL);

/* Unlike regular alloc_pages() there is no __alloc_pages_slowpath(). */

--
MST