Andrey, please take a look.
All other patches from Anatoly are applied already, except this one.
Worth to apply this one as well?
--
Best regards,
Konstantin Khorenko,
Virtuozzo Linux Kernel Team
On 10/21/2016 02:42 PM, Anatoly Stepanov wrote:
This is a backport of upstream (vanilla) commit:
commit 96c7a2ff21501691587e1ae969b83cbec8b78e08
Under certain conditions there might be a lot of
alloc_fdmem() invocations with order <= PAGE_ALLOC_COSTLY_ORDER.
For example: httpd which is doing a lot of fork() calls.
Real-life examples from our customers:
[532506.773243] httpd D ffff8803f5fecc20 0 939874 6606
[532506.773257] Call Trace:
[532506.773261] [<ffffffff8163ce29>] schedule+0x29/0x70
[532506.773264] [<ffffffff8163a9d5>] schedule_timeout+0x175/0x2d0
[532506.773272] [<ffffffff8108cc90>] ? internal_add_timer+0x70/0x70
[532506.773276] [<ffffffff8163c3ae>] io_schedule_timeout+0xae/0x130
[532506.773280] [<ffffffff8119be85>] wait_iff_congested+0x135/0x150
[532506.773284] [<ffffffff810a86e0>] ? wake_up_atomic_t+0x30/0x30
[532506.773288] [<ffffffff8119071f>] shrink_inactive_list+0x65f/0x6c0
[532506.773292] [<ffffffff81190f55>] shrink_lruvec+0x395/0x800
[532506.773296] [<ffffffff811914af>] shrink_zone+0xef/0x2d0
[532506.773300] [<ffffffff81191a30>] do_try_to_free_pages+0x170/0x530
[532506.773310] [<ffffffff81191ec5>] try_to_free_pages+0xd5/0x160
[532506.773315] [<ffffffff811850ab>] __alloc_pages_nodemask+0x8ab/0xc10
[532506.773320] [<ffffffff811cb2f9>] alloc_pages_current+0xa9/0x170
[532506.773324] [<ffffffff8119f8f8>] kmalloc_order+0x18/0x50
[532506.773327] [<ffffffff8119f956>] kmalloc_order_trace+0x26/0xa0
[532506.773332] [<ffffffff811d8c69>] __kmalloc+0x259/0x270
[532506.773337] [<ffffffff812184d0>] alloc_fdmem+0x20/0x50
[532506.773341] [<ffffffff812185ac>] alloc_fdtable+0x6c/0xe0
[532506.773344] [<ffffffff81218b69>] dup_fd+0x1f9/0x2d0
[532506.773354] [<ffffffff810797cf>] copy_process.part.30+0x87f/0x1510
[532506.773358] [<ffffffff8107a641>] do_fork+0xe1/0x320
[532506.773370] [<ffffffff8107a906>] SyS_clone+0x16/0x20
[532506.773376] [<ffffffff81648299>] stub_clone+0x69/0x90
[532506.773380] [<ffffffff81647f49>] ? system_call_fastpath+0x16/0x1b
[513890.005271] httpd D ffff880425db7230 0 811718 6606
[513890.005279] Call Trace:
[513890.005282] [<ffffffff8163ce29>] schedule+0x29/0x70
[513890.005284] [<ffffffff8163aa99>] schedule_timeout+0x239/0x2d0
[513890.005292] [<ffffffff8163c3ae>] io_schedule_timeout+0xae/0x130
[513890.005296] [<ffffffff8163c448>] io_schedule+0x18/0x20
[513890.005298] [<ffffffff812c6268>] get_request+0x218/0x780
[513890.005303] [<ffffffff812c8526>] blk_queue_bio+0xc6/0x3a0
[513890.005309] [<ffffffffa0002c59>] ? dm_make_request+0x119/0x170 [dm_mod]
[513890.005311] [<ffffffff812c3892>] generic_make_request+0xe2/0x130
[513890.005313] [<ffffffff812c3957>] submit_bio+0x77/0x1c0
[513890.005318] [<ffffffff811bf87e>] __swap_writepage+0x1be/0x260
[513890.005337] [<ffffffff811bf959>] swap_writepage+0x39/0x80
[513890.005340] [<ffffffff8118f68d>] shrink_page_list+0x4ad/0xa80
[513890.005343] [<ffffffff811902bb>] shrink_inactive_list+0x1fb/0x6c0
[513890.005345] [<ffffffff81190f55>] shrink_lruvec+0x395/0x800
[513890.005348] [<ffffffff811914af>] shrink_zone+0xef/0x2d0
[513890.005350] [<ffffffff81191a30>] do_try_to_free_pages+0x170/0x530
[513890.005353] [<ffffffff81191ec5>] try_to_free_pages+0xd5/0x160
[513890.005355] [<ffffffff811850ab>] __alloc_pages_nodemask+0x8ab/0xc10
[513890.005358] [<ffffffff811cb2f9>] alloc_pages_current+0xa9/0x170
[513890.005360] [<ffffffff8119f8f8>] kmalloc_order+0x18/0x50
[513890.005362] [<ffffffff8119f956>] kmalloc_order_trace+0x26/0xa0
[513890.005365] [<ffffffff811d8c69>] __kmalloc+0x259/0x270
[513890.005367] [<ffffffff812184d0>] alloc_fdmem+0x20/0x50
[513890.005369] [<ffffffff812185ac>] alloc_fdtable+0x6c/0xe0
[513890.005371] [<ffffffff81218b69>] dup_fd+0x1f9/0x2d0
[513890.005376] [<ffffffff810797cf>] copy_process.part.30+0x87f/0x1510
[513890.005378] [<ffffffff8107a641>] do_fork+0xe1/0x320
[513890.005380] [<ffffffff8107a906>] SyS_clone+0x16/0x20
[513890.005382] [<ffffffff81648299>] stub_clone+0x69/0x90
We observed that sometimes kswapd cannot handle this which
causes many direct reclaim attempts which in turn:
1. Increases iowait time due to congestion_wait
2. Increases number of block reqs per second due to
page swapping and writeback
3. May induce OOMs
So it's better DO NOT try that hard to allocate contiguous
area, and fallback to vmalloc() as soon as possible.
Signed-off-by: Anatoly Stepanov <astepa...@cloudlinux.com>
---
fs/file.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/file.c b/fs/file.c
index 366d9bb..3f65ba0 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -36,7 +36,7 @@ static void *alloc_fdmem(size_t size)
* vmalloc() if the allocation size will be considered "large" by the
VM.
*/
if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
- void *data = kmalloc(size, GFP_KERNEL|__GFP_NOWARN);
+ void *data = kmalloc(size,
GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY);
if (data != NULL)
return data;
}
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