mm/vmalloc: use batched page requests in bulk-allocator

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.

<snip>
[   62.512621] RIP: 0010:__alloc_pages_bulk+0xa9f/0xbb0
[   62.512628] Code: ff 8b 44 24 48 44 29 f8 83 f8 01 0f 84 ea fe ff ff e9 07 f6 ff ff 48 8b 44 24 60 48 89 28 e9 00 f9 ff ff fb 66 0f 1f 44 00 00 <e9> e8 fd ff ff 65 48 01 51 10 e9 3e fe ff ff 48 8b 44 24 78 4d 89
[   62.512629] RSP: 0018:ffffa7bfc29ffd20 EFLAGS: 00000206
[   62.512631] RAX: 0000000000000200 RBX: ffffcd5405421888 RCX: ffff8c36ffdeb928
[   62.512632] RDX: 0000000000040000 RSI: ffffa896f06b2ff8 RDI: ffffcd5405421880
[   62.512633] RBP: ffffcd5405421880 R08: 000000000000007d R09: ffffffffffffffff
[   62.512634] R10: ffffffff9d63c084 R11: 00000000ffffffff R12: ffff8c373ffaeb80
[   62.512635] R13: ffff8c36ffdf65f8 R14: ffff8c373ffaeb80 R15: 0000000000040000
[   62.512637] FS:  0000000000000000(0000) GS:ffff8c36ffdc0000(0000) knlGS:0000000000000000
[   62.512638] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   62.512639] CR2: 000055c8e2fe8610 CR3: 0000000c13e10000 CR4: 00000000000006e0
[   62.512641] Call Trace:
[   62.512646]  __vmalloc_node_range+0x11c/0x2d0
[   62.512649]  ? full_fit_alloc_test+0x140/0x140 [test_vmalloc]
[   62.512654]  __vmalloc_node+0x4b/0x70
[   62.512656]  ? fix_size_alloc_test+0x44/0x60 [test_vmalloc]
[   62.512659]  fix_size_alloc_test+0x44/0x60 [test_vmalloc]
[   62.512662]  test_func+0xe7/0x1f0 [test_vmalloc]
[   62.512666]  ? fix_align_alloc_test+0x50/0x50 [test_vmalloc]
[   62.512668]  kthread+0x11a/0x140
[   62.512671]  ? set_kthread_struct+0x40/0x40
[   62.512672]  ret_from_fork+0x22/0x30
<snip>

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: Stephen Rothwell <sfr@canb.auug.org.au>

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d5cd5280514966b7929cb0ede7994244421e275a..24bc65f02d040b126fe247eb544a66f2b5aff263 100644 (file)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2779,7 +2779,7 @@ 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;
 
@@ -2789,10 +2789,32 @@ 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.