The commit 387ba26fb1cb ("mm/page_alloc: add a bulk page allocator") added
__alloc_pages_bulk() along with the page_list argument. The next
commit 0f87d9d30f21 ("mm/page_alloc: add an array-based interface to the
bulk page allocator") added the array-based argument. As it turns out, the
page_list argument has no users in the current tree (if it ever had any).
Dropping it allows for a slight simplification and eliminates some
unnecessary checks, now that page_array is required.
Also, note that the removal of the page_list argument was proposed before
in the thread below, where Matthew Wilcox mentions that:
"""
Iterating a linked list is _expensive_. It is about 10x quicker to
iterate an array than a linked list.
"""
(https://lore.kernel.org/linux-mm/20231025093254.xvomlctwhcuerzky@xxxxxxxxxxxxxxxxxxx)
Signed-off-by: Luiz Capitulino <luizcap@xxxxxxxxxx>
---
include/linux/gfp.h | 8 ++------
mm/mempolicy.c | 14 +++++++-------
mm/page_alloc.c | 39 ++++++++++++---------------------------
3 files changed, 21 insertions(+), 40 deletions(-)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index b0fe9f62d15b6..eebed36443b35 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -212,7 +212,6 @@ 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__))
@@ -223,11 +222,8 @@ unsigned long alloc_pages_bulk_array_mempolicy_noprof(gfp_t gfp,
alloc_hooks(alloc_pages_bulk_array_mempolicy_noprof(__VA_ARGS__))
/* Bulk allocate order-0 pages */
-#define alloc_pages_bulk_list(_gfp, _nr_pages, _list) \
- __alloc_pages_bulk(_gfp, numa_mem_id(), NULL, _nr_pages, _list, NULL)
-
#define alloc_pages_bulk_array(_gfp, _nr_pages, _page_array) \
- __alloc_pages_bulk(_gfp, numa_mem_id(), NULL, _nr_pages, NULL, _page_array)
+ __alloc_pages_bulk(_gfp, numa_mem_id(), NULL, _nr_pages, _page_array)
static inline unsigned long
alloc_pages_bulk_array_node_noprof(gfp_t gfp, int nid, unsigned long nr_pages,
@@ -236,7 +232,7 @@ alloc_pages_bulk_array_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, NULL, page_array);
+ return alloc_pages_bulk_noprof(gfp, nid, NULL, nr_pages, page_array);
}
#define alloc_pages_bulk_array_node(...) \
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 04f35659717ae..42a7b07ccc15a 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2375,13 +2375,13 @@ static unsigned long alloc_pages_bulk_array_interleave(gfp_t gfp,
if (delta) {
nr_allocated = alloc_pages_bulk_noprof(gfp,
interleave_nodes(pol), NULL,
- nr_pages_per_node + 1, NULL,
+ nr_pages_per_node + 1,
page_array);
delta--;
} else {
nr_allocated = alloc_pages_bulk_noprof(gfp,
interleave_nodes(pol), NULL,
- nr_pages_per_node, NULL, page_array);
+ nr_pages_per_node, page_array);
}
page_array += nr_allocated;
@@ -2430,7 +2430,7 @@ static unsigned long alloc_pages_bulk_array_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,
- NULL, page_array);
+ page_array);
page_array += nr_allocated;
total_allocated += nr_allocated;
/* if that's all the pages, no need to interleave */
@@ -2493,7 +2493,7 @@ static unsigned long alloc_pages_bulk_array_weighted_interleave(gfp_t gfp,
if (!node_pages)
break;
nr_allocated = __alloc_pages_bulk(gfp, node, NULL, node_pages,
- NULL, page_array);
+ page_array);
page_array += nr_allocated;
total_allocated += nr_allocated;
if (total_allocated == nr_pages)
@@ -2517,11 +2517,11 @@ static unsigned long alloc_pages_bulk_array_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, NULL, page_array);
+ nr_pages, page_array);
if (nr_allocated < nr_pages)
nr_allocated += alloc_pages_bulk_noprof(gfp, numa_node_id(), NULL,
- nr_pages - nr_allocated, NULL,
+ nr_pages - nr_allocated,
page_array + nr_allocated);
return nr_allocated;
}
@@ -2557,7 +2557,7 @@ unsigned long alloc_pages_bulk_array_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, NULL, page_array);
+ nr_pages, 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 cae7b93864c23..4ce77a0e8d9a7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4531,28 +4531,23 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
}
/*
- * __alloc_pages_bulk - Allocate a number of order-0 pages to a list or array
+ * __alloc_pages_bulk - Allocate a number of order-0 pages to an 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 on the list or array
- * @page_list: Optional list to store the allocated pages
- * @page_array: Optional array to store the pages
+ * @nr_pages: The number of pages desired in the array
+ * @page_array: 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 page_list if page_list
- * is not NULL, otherwise it is assumed that the page_array is valid.
+ * allocate nr_pages quickly. Pages are added to the page_array.
*
- * 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
+ * Note that 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 on the list or array.
+ * Returns the number of pages in the 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;
@@ -4570,7 +4565,7 @@ 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 (page_array && nr_populated < nr_pages && page_array[nr_populated])
+ while (nr_populated < nr_pages && page_array[nr_populated])
nr_populated++;
/* No pages requested? */
@@ -4578,7 +4573,7 @@ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid,
goto out;
/* Already populated array? */
- if (unlikely(page_array && nr_pages - nr_populated == 0))
+ if (unlikely(nr_pages - nr_populated == 0))
goto out;
/* Bulk allocator does not support memcg accounting. */
@@ -4660,7 +4655,7 @@ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid,
while (nr_populated < nr_pages) {
/* Skip existing pages */
- if (page_array && page_array[nr_populated]) {
+ if (page_array[nr_populated]) {
nr_populated++;
continue;
}
@@ -4678,11 +4673,7 @@ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid,
nr_account++;
prep_new_page(page, 0, gfp, 0);
- if (page_list)
- list_add(&page->lru, page_list);
- else
- page_array[nr_populated] = page;
- nr_populated++;
+ page_array[nr_populated++] = page;
}
pcp_spin_unlock(pcp);
@@ -4699,14 +4690,8 @@ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid,
failed:
page = __alloc_pages_noprof(gfp, 0, preferred_nid, nodemask);
- if (page) {
- if (page_list)
- list_add(&page->lru, page_list);
- else
- page_array[nr_populated] = page;
- nr_populated++;
- }
-
+ if (page)
+ page_array[nr_populated++] = page;
goto out;
}
EXPORT_SYMBOL_GPL(alloc_pages_bulk_noprof);
--
2.47.1
