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Message-ID: <20251014083230.1181072-2-zhaoyang.huang@unisoc.com>
Date: Tue, 14 Oct 2025 16:32:29 +0800
From: "zhaoyang.huang" <zhaoyang.huang@...soc.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
David Hildenbrand
<david@...hat.com>,
Matthew Wilcox <willy@...radead.org>,
Mel Gorman
<mgorman@...hsingularity.net>,
Vlastimil Babka <vbabka@...e.cz>,
Sumit Semwal
<sumit.semwal@...aro.org>,
Benjamin Gaignard
<benjamin.gaignard@...labora.com>,
Brian Starkey <Brian.Starkey@....com>,
John Stultz <jstultz@...gle.com>,
"T . J . Mercier" <tjmercier@...gle.com>,
Christian König <christian.koenig@....com>,
<linux-media@...r.kernel.org>, <dri-devel@...ts.freedesktop.org>,
<linaro-mm-sig@...ts.linaro.org>, <linux-mm@...ck.org>,
<linux-kernel@...r.kernel.org>,
Zhaoyang Huang <huangzhaoyang@...il.com>, <steve.kang@...soc.com>
Subject: [PATCH 1/2] mm: call back alloc_pages_bulk_list since it is useful
From: Zhaoyang Huang <zhaoyang.huang@...soc.com>
commit c8b979530f27 ("mm: alloc_pages_bulk_noprof: drop page_list
argument") drops alloc_pages_bulk_list. This commit would like to call back
it since it is proved to be helpful to the drivers which allocate a bulk of
pages(see patch of 2 in this series ).
I do notice that Matthew's comment of the time cost of iterating a list.
However, I also observed in our test that the extra page_array's allocation
could be more expensive than cpu iteration when direct reclaiming happens
when ram is low[1]. IMHO, could we leave the API here to have the users
choose between the array or list according to their scenarios.
[1]
android.hardwar-728 [002] ..... 334.573875: system_heap_do_allocate: Execution time: order 0 1 us
android.hardwar-728 [002] ..... 334.573879: system_heap_do_allocate: Execution time: order 0 2 us
android.hardwar-728 [002] ..... 334.574239: system_heap_do_allocate: Execution time: order 0 354 us
android.hardwar-728 [002] ..... 334.574247: system_heap_do_allocate: Execution time: order 0 4 us
android.hardwar-728 [002] ..... 334.574250: system_heap_do_allocate: Execution time: order 0 2 us
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@...soc.com>
---
include/linux/gfp.h | 9 +++++++--
mm/mempolicy.c | 14 +++++++-------
mm/page_alloc.c | 39 +++++++++++++++++++++++++++------------
3 files changed, 41 insertions(+), 21 deletions(-)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 5ebf26fcdcfa..f1540c9fcd87 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -231,6 +231,7 @@ struct folio *__folio_alloc_noprof(gfp_t gfp, unsigned int order, int preferred_
unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid,
nodemask_t *nodemask, int nr_pages,
+ struct list_head *page_list,
struct page **page_array);
#define __alloc_pages_bulk(...) alloc_hooks(alloc_pages_bulk_noprof(__VA_ARGS__))
@@ -242,7 +243,11 @@ unsigned long alloc_pages_bulk_mempolicy_noprof(gfp_t gfp,
/* Bulk allocate order-0 pages */
#define alloc_pages_bulk(_gfp, _nr_pages, _page_array) \
- __alloc_pages_bulk(_gfp, numa_mem_id(), NULL, _nr_pages, _page_array)
+ __alloc_pages_bulk(_gfp, numa_mem_id(), NULL, _nr_pages, NULL, _page_array)
+
+#define alloc_pages_bulk_list(_gfp, _nr_pages, _list) \
+ __alloc_pages_bulk(_gfp, numa_mem_id(), NULL, _nr_pages, _list, NULL)
+
static inline unsigned long
alloc_pages_bulk_node_noprof(gfp_t gfp, int nid, unsigned long nr_pages,
@@ -251,7 +256,7 @@ alloc_pages_bulk_node_noprof(gfp_t gfp, int nid, unsigned long nr_pages,
if (nid == NUMA_NO_NODE)
nid = numa_mem_id();
- return alloc_pages_bulk_noprof(gfp, nid, NULL, nr_pages, page_array);
+ return alloc_pages_bulk_noprof(gfp, nid, NULL, nr_pages, NULL, page_array);
}
#define alloc_pages_bulk_node(...) \
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index eb83cff7db8c..26274302ee01 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2537,13 +2537,13 @@ static unsigned long alloc_pages_bulk_interleave(gfp_t gfp,
if (delta) {
nr_allocated = alloc_pages_bulk_noprof(gfp,
interleave_nodes(pol), NULL,
- nr_pages_per_node + 1,
+ nr_pages_per_node + 1, NULL,
page_array);
delta--;
} else {
nr_allocated = alloc_pages_bulk_noprof(gfp,
interleave_nodes(pol), NULL,
- nr_pages_per_node, page_array);
+ nr_pages_per_node, NULL, page_array);
}
page_array += nr_allocated;
@@ -2593,7 +2593,7 @@ static unsigned long alloc_pages_bulk_weighted_interleave(gfp_t gfp,
if (weight && node_isset(node, nodes)) {
node_pages = min(rem_pages, weight);
nr_allocated = __alloc_pages_bulk(gfp, node, NULL, node_pages,
- page_array);
+ NULL, page_array);
page_array += nr_allocated;
total_allocated += nr_allocated;
/* if that's all the pages, no need to interleave */
@@ -2658,7 +2658,7 @@ static unsigned long alloc_pages_bulk_weighted_interleave(gfp_t gfp,
if (!node_pages)
break;
nr_allocated = __alloc_pages_bulk(gfp, node, NULL, node_pages,
- page_array);
+ NULL, page_array);
page_array += nr_allocated;
total_allocated += nr_allocated;
if (total_allocated == nr_pages)
@@ -2682,11 +2682,11 @@ static unsigned long alloc_pages_bulk_preferred_many(gfp_t gfp, int nid,
preferred_gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL);
nr_allocated = alloc_pages_bulk_noprof(preferred_gfp, nid, &pol->nodes,
- nr_pages, page_array);
+ nr_pages, NULL, page_array);
if (nr_allocated < nr_pages)
nr_allocated += alloc_pages_bulk_noprof(gfp, numa_node_id(), NULL,
- nr_pages - nr_allocated,
+ nr_pages - nr_allocated, NULL,
page_array + nr_allocated);
return nr_allocated;
}
@@ -2722,7 +2722,7 @@ unsigned long alloc_pages_bulk_mempolicy_noprof(gfp_t gfp,
nid = numa_node_id();
nodemask = policy_nodemask(gfp, pol, NO_INTERLEAVE_INDEX, &nid);
return alloc_pages_bulk_noprof(gfp, nid, nodemask,
- nr_pages, page_array);
+ nr_pages, NULL, page_array);
}
int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d1d037f97c5f..a95bdd8cbf5b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4940,23 +4940,28 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
}
/*
- * __alloc_pages_bulk - Allocate a number of order-0 pages to an array
+ * __alloc_pages_bulk - Allocate a number of order-0 pages to a list or array
* @gfp: GFP flags for the allocation
* @preferred_nid: The preferred NUMA node ID to allocate from
* @nodemask: Set of nodes to allocate from, may be NULL
- * @nr_pages: The number of pages desired in the array
- * @page_array: Array to store the pages
+ * @nr_pages: The number of pages desired on the list or array
+ * @page_list: Optional list to store the allocated pages
+ * @page_array: Optional array to store the pages
*
* This is a batched version of the page allocator that attempts to
- * allocate nr_pages quickly. Pages are added to the page_array.
+ * allocate nr_pages quickly. Pages are added to page_list if page_list
+ * is not NULL, otherwise it is assumed that the page_array is valid.
*
- * Note that only NULL elements are populated with pages and nr_pages
+ * For lists, nr_pages is the number of pages that should be allocated.
+ *
+ * For arrays, only NULL elements are populated with pages and nr_pages
* is the maximum number of pages that will be stored in the array.
*
- * Returns the number of pages in the array.
+ * Returns the number of pages on the list or array.
*/
unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid,
nodemask_t *nodemask, int nr_pages,
+ struct list_head *page_list,
struct page **page_array)
{
struct page *page;
@@ -4974,7 +4979,7 @@ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid,
* Skip populated array elements to determine if any pages need
* to be allocated before disabling IRQs.
*/
- while (nr_populated < nr_pages && page_array[nr_populated])
+ while (page_array && nr_populated < nr_pages && page_array[nr_populated])
nr_populated++;
/* No pages requested? */
@@ -4982,7 +4987,7 @@ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid,
goto out;
/* Already populated array? */
- if (unlikely(nr_pages - nr_populated == 0))
+ if (unlikely(page_array && nr_pages - nr_populated == 0))
goto out;
/* Bulk allocator does not support memcg accounting. */
@@ -5064,7 +5069,7 @@ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid,
while (nr_populated < nr_pages) {
/* Skip existing pages */
- if (page_array[nr_populated]) {
+ if (page_array && page_array[nr_populated]) {
nr_populated++;
continue;
}
@@ -5083,7 +5088,11 @@ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid,
prep_new_page(page, 0, gfp, 0);
set_page_refcounted(page);
- page_array[nr_populated++] = page;
+ if (page_list)
+ list_add(&page->lru, page_list);
+ else
+ page_array[nr_populated] = page;
+ nr_populated++;
}
pcp_spin_unlock(pcp);
@@ -5100,8 +5109,14 @@ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid,
failed:
page = __alloc_pages_noprof(gfp, 0, preferred_nid, nodemask);
- if (page)
- page_array[nr_populated++] = page;
+ if (page) {
+ if (page_list)
+ list_add(&page->lru, page_list);
+ else
+ page_array[nr_populated] = page;
+ nr_populated++;
+ }
+
goto out;
}
EXPORT_SYMBOL_GPL(alloc_pages_bulk_noprof);
--
2.25.1
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