Messages in this thread |  | | From | Roman Gushchin <> | Subject | Re: [PATCH] igb: don't reuse pages with pfmemalloc flag | Date | Thu, 23 Oct 2014 11:52:03 +0400 |
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Thank you!
Probably we should add it to stable trees too?
-- Regards, Roman
22.10.2014, 22:30, "Jeff Kirsher" <jeffrey.t.kirsher@intel.com>: > On Wed, 2014-10-22 at 17:50 +0400, Roman Gushchin wrote: >> Incoming packet is dropped silently by sk_filter(), if the skb was >> allocated from pfmemalloc reserves and the corresponding socket is >> not marked with the SOCK_MEMALLOC flag. >> >> Igb driver allocates pages for DMA with __skb_alloc_page(), which >> calls alloc_pages_node() with the __GFP_MEMALLOC flag. So, in case >> of OOM condition, igb can get pages with pfmemalloc flag set. >> >> If an incoming packet hits the pfmemalloc page and is large enough >> (small packets are copying into the memory, allocated with >> netdev_alloc_skb_ip_align(), so they are not affected), it will be >> dropped. >> >> This behavior is ok under high memory pressure, but the problem is >> that the igb driver reuses these mapped pages. So, packets are still >> dropping even if all memory issues are gone and there is a plenty >> of free memory. >> >> In my case, some TCP sessions hang on a small percentage (< 0.1%) >> of machines days after OOMs. >> >> Fix this by avoiding reuse of such pages. >> >> Signed-off-by: Roman Gushchin <klamm@yandex-team.ru> >> --- >> drivers/net/ethernet/intel/igb/igb_main.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) > > Thanks Roman, I have added you patch to my queue. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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