[patch 100/262] mm/vmalloc: introduce alloc_pages_bulk_array_mempolicy to accelerate memory allocation

Andrew Morton
2021-11-05T20:39:56Z

From: Chen Wandun <chenwandun@huawei.com>
Subject: mm/vmalloc: introduce alloc_pages_bulk_array_mempolicy to accelerate memory allocation

"mm/vmalloc: fix numa spreading for large hash tables" 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

[akpm@linux-foundation.org: coding style fixes]
[akpm@linux-foundation.org: make two functions static]
[akpm@linux-foundation.org: fix CONFIG_NUMA=n build]
Link: https://lkml.kernel.org/r/20211021080744.874701-3-chenwandun@huawei.com
Signed-off-by: Chen Wandun <chenwandun@huawei.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

include/linux/gfp.h | 4 ++
mm/mempolicy.c | 82 ++++++++++++++++++++++++++++++++++++++++++
mm/vmalloc.c | 20 ++++++++--
3 files changed, 102 insertions(+), 4 deletions(-)

--- a/include/linux/gfp.h~mm-vmalloc-introduce-alloc_pages_bulk_array_mempolicy-to-accelerate-memory-allocation
+++ a/include/linux/gfp.h
@@ -535,6 +535,10 @@ unsigned long __alloc_pages_bulk(gfp_t g
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)
--- a/mm/mempolicy.c~mm-vmalloc-introduce-alloc_pages_bulk_array_mempolicy-to-accelerate-memory-allocation
+++ a/mm/mempolicy.c
@@ -2196,6 +2196,88 @@ struct page *alloc_pages(gfp_t gfp, unsi
}
EXPORT_SYMBOL(alloc_pages);

+static 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;
+}
+
+static 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));
--- a/mm/vmalloc.c~mm-vmalloc-introduce-alloc_pages_bulk_array_mempolicy-to-accelerate-memory-allocation
+++ a/mm/vmalloc.c
@@ -2843,7 +2843,7 @@ 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;

@@ -2855,8 +2855,20 @@ 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 can't
+ * 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 (IS_ENABLED(CONFIG_NUMA) && 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();
@@ -2868,7 +2880,7 @@ 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.
_