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Date: Thu, 06 Feb 2014 10:42:42 -0800 From: Eric Dumazet <eric.dumazet@...il.com> To: David Miller <davem@...emloft.net> Cc: netdev <netdev@...r.kernel.org>, David Rientjes <rientjes@...gle.com>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org> Subject: [PATCH] net: use __GFP_NORETRY for high order allocations From: Eric Dumazet <edumazet@...gle.com> 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@...gle.com> Acked-by: David Rientjes <rientjes@...gle.com> --- net/core/sock.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/core/sock.c b/net/core/sock.c index 0c127dcdf6a8..5b6a9431b017 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1775,7 +1775,9 @@ struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len, while (order) { if (npages >= 1 << order) { page = alloc_pages(sk->sk_allocation | - __GFP_COMP | __GFP_NOWARN, + __GFP_COMP | + __GFP_NOWARN | + __GFP_NORETRY, order); if (page) goto fill_page; @@ -1845,7 +1847,7 @@ bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t prio) gfp_t gfp = prio; if (order) - gfp |= __GFP_COMP | __GFP_NOWARN; + gfp |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY; pfrag->page = alloc_pages(gfp, order); if (likely(pfrag->page)) { pfrag->offset = 0; -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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