From cc5bbd205258f55bf3fd1389a15191ae0acc439a Mon Sep 17 00:00:00 2001
From: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Date: Thu, 2 Sep 2021 14:57:16 -0700
Subject: [PATCH] mm/vmalloc: use batched page requests in bulk-allocator
References: bsc#1190208 (MM functional and performance backports)
Patch-mainline: v5.15-rc1
Git-commit: 343ab8178f318b6006d54865972ff9c433b29e10
In case of simultaneous vmalloc allocations, for example it is 1GB and 12
CPUs my system is able to hit "BUG: soft lockup" for !CONFIG_PREEMPT
kernel.
RIP: 0010:__alloc_pages_bulk+0xa9f/0xbb0
Call Trace:
__vmalloc_node_range+0x11c/0x2d0
__vmalloc_node+0x4b/0x70
fix_size_alloc_test+0x44/0x60 [test_vmalloc]
test_func+0xe7/0x1f0 [test_vmalloc]
kthread+0x11a/0x140
ret_from_fork+0x22/0x30
To address this issue invoke a bulk-allocator many times until all pages
are obtained, i.e. do batched page requests adding cond_resched()
meanwhile to reschedule. Batched value is hard-coded and is 100 pages per
call.
Link: https://lkml.kernel.org/r/20210707182639.31282-1-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
mm/vmalloc.c | 32 +++++++++++++++++++++++++++-----
1 file changed, 27 insertions(+), 5 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 47c3a551b6dc..ba8d6d45af7b 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2801,7 +2801,7 @@ EXPORT_SYMBOL_GPL(vmap_pfn);
static inline unsigned int
vm_area_alloc_pages(gfp_t gfp, int nid,
- unsigned int order, unsigned long nr_pages, struct page **pages)
+ unsigned int order, unsigned int nr_pages, struct page **pages)
{
unsigned int nr_allocated = 0;
@@ -2811,10 +2811,32 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
* to fails, fallback to a single page allocator that is
* more permissive.
*/
- if (!order)
- nr_allocated = alloc_pages_bulk_array_node(
- gfp, nid, nr_pages, pages);
- else
+ if (!order) {
+ while (nr_allocated < nr_pages) {
+ unsigned int nr, nr_pages_request;
+
+ /*
+ * A maximum allowed request is hard-coded and is 100
+ * pages per call. That is done in order to prevent a
+ * long preemption off scenario in the bulk-allocator
+ * so the range is [1:100].
+ */
+ nr_pages_request = min(100U, nr_pages - nr_allocated);
+
+ nr = alloc_pages_bulk_array_node(gfp, nid,
+ nr_pages_request, pages + nr_allocated);
+
+ nr_allocated += nr;
+ cond_resched();
+
+ /*
+ * If zero or pages were obtained partly,
+ * fallback to a single page allocator.
+ */
+ if (nr != nr_pages_request)
+ break;
+ }
+ } else
/*
* Compound pages required for remap_vmalloc_page if
* high-order pages.