sock_alloc_send_pskb() & sk_page_frag_refill()
have a loop trying high order allocations to prepare
skb with low number of fragments as this increases performance.

Problem is that under memory pressure/fragmentation, this can
trigger OOM while the intent was only to try the high order
allocations, then fallback to order-0 allocations.

We had various reports from unexpected regressions.

According to David, setting __GFP_NORETRY should be fine,
as the asynchronous compaction is still enabled, and this
will prevent OOM from kicking as in :

CFSClientEventm invoked oom-killer: gfp_mask=0x42d0, order=3, oom_adj=0,
oom_score_adj=0, oom_score_badness=2 (enabled),memcg_scoring=disabled
CFSClientEventm

Call Trace:
 [<ffffffff8043766c>] dump_header+0xe1/0x23e
 [<ffffffff80437a02>] oom_kill_process+0x6a/0x323
 [<ffffffff80438443>] out_of_memory+0x4b3/0x50d
 [<ffffffff8043a4a6>] __alloc_pages_may_oom+0xa2/0xc7
 [<ffffffff80236f42>] __alloc_pages_nodemask+0x1002/0x17f0
 [<ffffffff8024bd23>] alloc_pages_current+0x103/0x2b0
 [<ffffffff8028567f>] sk_page_frag_refill+0x8f/0x160
 [<ffffffff80295fa0>] tcp_sendmsg+0x560/0xee0
 [<ffffffff802a5037>] inet_sendmsg+0x67/0x100
 [<ffffffff80283c9c>] __sock_sendmsg_nosec+0x6c/0x90
 [<ffffffff80283e85>] sock_sendmsg+0xc5/0xf0
 [<ffffffff802847b6>] __sys_sendmsg+0x136/0x430
 [<ffffffff80284ec8>] sys_sendmsg+0x88/0x110
 [<ffffffff80711472>] system_call_fastpath+0x16/0x1b
Out of Memory: Kill process 2856 (bash) score 9999 or sacrifice child
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>