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Message-ID: <20211018123710.1540996-3-chenwandun@huawei.com>
Date: Mon, 18 Oct 2021 20:37:10 +0800
From: Chen Wandun <chenwandun@...wei.com>
To: <akpm@...ux-foundation.org>, <npiggin@...il.com>,
<linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
<edumazet@...gle.com>, <wangkefeng.wang@...wei.com>,
<guohanjun@...wei.com>, <shakeelb@...gle.com>, <urezki@...il.com>
CC: <chenwandun@...wei.com>
Subject: [PATCH v2 2/2] mm/vmalloc: introduce alloc_pages_bulk_array_mempolicy to accelerate memory allocation
It will cause significant performance regressions in some situations
as Andrew mentioned in [1]. The main situation is vmalloc, vmalloc
will allocate pages with NUMA_NO_NODE by default, that will result
in alloc page one by one;
In order to solve this, __alloc_pages_bulk and mempolicy should be
considered at the same time.
1) If node is specified in memory allocation request, it will alloc
all pages by __alloc_pages_bulk.
2) If interleaving allocate memory, it will cauculate how many pages
should be allocated in each node, and use __alloc_pages_bulk to alloc
pages in each node.
[1]: https://lore.kernel.org/lkml/CALvZod4G3SzP3kWxQYn0fj+VgG-G3yWXz=gz17+3N57ru1iajw@mail.gmail.com/t/#m750c8e3231206134293b089feaa090590afa0f60
Reviewed-by: Uladzislau Rezki (Sony) <urezki@...il.com>
Signed-off-by: Chen Wandun <chenwandun@...wei.com>
---
include/linux/gfp.h | 4 +++
mm/mempolicy.c | 82 +++++++++++++++++++++++++++++++++++++++++++++
mm/vmalloc.c | 20 ++++++++---
3 files changed, 102 insertions(+), 4 deletions(-)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 55b2ec1f965a..cd98c858fc74 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -535,6 +535,10 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid,
struct list_head *page_list,
struct page **page_array);
+unsigned long alloc_pages_bulk_array_mempolicy(gfp_t gfp,
+ unsigned long nr_pages,
+ struct page **page_array);
+
/* Bulk allocate order-0 pages */
static inline unsigned long
alloc_pages_bulk_list(gfp_t gfp, unsigned long nr_pages, struct list_head *list)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 1592b081c58e..56bb1fe4d179 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2202,6 +2202,88 @@ struct page *alloc_pages(gfp_t gfp, unsigned order)
}
EXPORT_SYMBOL(alloc_pages);
+unsigned long alloc_pages_bulk_array_interleave(gfp_t gfp,
+ struct mempolicy *pol, unsigned long nr_pages,
+ struct page **page_array)
+{
+ int nodes;
+ unsigned long nr_pages_per_node;
+ int delta;
+ int i;
+ unsigned long nr_allocated;
+ unsigned long total_allocated = 0;
+
+ nodes = nodes_weight(pol->nodes);
+ nr_pages_per_node = nr_pages / nodes;
+ delta = nr_pages - nodes * nr_pages_per_node;
+
+ for (i = 0; i < nodes; i++) {
+ if (delta) {
+ nr_allocated = __alloc_pages_bulk(gfp,
+ interleave_nodes(pol), NULL,
+ nr_pages_per_node + 1, NULL,
+ page_array);
+ delta--;
+ } else {
+ nr_allocated = __alloc_pages_bulk(gfp,
+ interleave_nodes(pol), NULL,
+ nr_pages_per_node, NULL, page_array);
+ }
+
+ page_array += nr_allocated;
+ total_allocated += nr_allocated;
+ }
+
+ return total_allocated;
+}
+
+unsigned long alloc_pages_bulk_array_preferred_many(gfp_t gfp, int nid,
+ struct mempolicy *pol, unsigned long nr_pages,
+ struct page **page_array)
+{
+ gfp_t preferred_gfp;
+ unsigned long nr_allocated = 0;
+
+ preferred_gfp = gfp | __GFP_NOWARN;
+ preferred_gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL);
+
+ nr_allocated = __alloc_pages_bulk(preferred_gfp, nid, &pol->nodes,
+ nr_pages, NULL, page_array);
+
+ if (nr_allocated < nr_pages)
+ nr_allocated += __alloc_pages_bulk(gfp, numa_node_id(), NULL,
+ nr_pages - nr_allocated, NULL,
+ page_array + nr_allocated);
+ return nr_allocated;
+}
+
+/* alloc pages bulk and mempolicy should be considered at the
+ * same time in some situation such as vmalloc.
+ *
+ * It can accelerate memory allocation especially interleaving
+ * allocate memory.
+ */
+unsigned long alloc_pages_bulk_array_mempolicy(gfp_t gfp,
+ unsigned long nr_pages, struct page **page_array)
+{
+ struct mempolicy *pol = &default_policy;
+
+ if (!in_interrupt() && !(gfp & __GFP_THISNODE))
+ pol = get_task_policy(current);
+
+ if (pol->mode == MPOL_INTERLEAVE)
+ return alloc_pages_bulk_array_interleave(gfp, pol,
+ nr_pages, page_array);
+
+ if (pol->mode == MPOL_PREFERRED_MANY)
+ return alloc_pages_bulk_array_preferred_many(gfp,
+ numa_node_id(), pol, nr_pages, page_array);
+
+ return __alloc_pages_bulk(gfp, policy_node(gfp, pol, numa_node_id()),
+ policy_nodemask(gfp, pol), nr_pages, NULL,
+ page_array);
+}
+
int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
{
struct mempolicy *pol = mpol_dup(vma_policy(src));
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 87552a4018aa..19b34c266fac 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2825,7 +2825,7 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
* to fails, fallback to a single page allocator that is
* more permissive.
*/
- if (!order && nid != NUMA_NO_NODE) {
+ if (!order) {
while (nr_allocated < nr_pages) {
unsigned int nr, nr_pages_request;
@@ -2837,8 +2837,20 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
*/
nr_pages_request = min(100U, nr_pages - nr_allocated);
- nr = alloc_pages_bulk_array_node(gfp, nid,
- nr_pages_request, pages + nr_allocated);
+ /* memory allocation should consider mempolicy, we cant
+ * wrongly use nearest node when nid == NUMA_NO_NODE,
+ * otherwise memory may be allocated in only one node,
+ * but mempolcy want to alloc memory by interleaving.
+ */
+ if (nid == NUMA_NO_NODE)
+ nr = alloc_pages_bulk_array_mempolicy(gfp,
+ nr_pages_request,
+ pages + nr_allocated);
+
+ else
+ nr = alloc_pages_bulk_array_node(gfp, nid,
+ nr_pages_request,
+ pages + nr_allocated);
nr_allocated += nr;
cond_resched();
@@ -2850,7 +2862,7 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
if (nr != nr_pages_request)
break;
}
- } else if (order)
+ } else
/*
* Compound pages required for remap_vmalloc_page if
* high-order pages.
--
2.25.1
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