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authorAlexander Duyck <alexander.h.duyck@redhat.com>2014-12-09 19:40:42 -0800
committerDavid S. Miller <davem@davemloft.net>2014-12-10 13:31:57 -0500
commitffde7328a36d16e626bae8468571858d71cd010b (patch)
treec84689c687b51d6fe70306f28cb045fa43f9ba59 /include/linux/skbuff.h
parent6e5f59aacbf9527dfe425541c78cb8c56623e7eb (diff)
net: Split netdev_alloc_frag into __alloc_page_frag and add __napi_alloc_frag
This patch splits the netdev_alloc_frag function up so that it can be used on one of two page frag pools instead of being fixed on the netdev_alloc_cache. By doing this we can add a NAPI specific function __napi_alloc_frag that accesses a pool that is only used from softirq context. The advantage to this is that we do not need to call local_irq_save/restore which can be a significant savings. I also took the opportunity to refactor the core bits that were placed in __alloc_page_frag. First I updated the allocation to do either a 32K allocation or an order 0 page. This is based on the changes in commmit d9b2938aa where it was found that latencies could be reduced in case of failures. Then I also rewrote the logic to work from the end of the page to the start. By doing this the size value doesn't have to be used unless we have run out of space for page fragments. Finally I cleaned up the atomic bits so that we just do an atomic_sub_and_test and if that returns true then we set the page->_count via an atomic_set. This way we can remove the extra conditional for the atomic_read since it would have led to an atomic_inc in the case of success anyway. Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/skbuff.h')
-rw-r--r--include/linux/skbuff.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index ab0bc43c82a4..736cc99f3f6c 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2164,6 +2164,8 @@ static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
}
+void *napi_alloc_frag(unsigned int fragsz);
+
/**
* __dev_alloc_pages - allocate page for network Rx
* @gfp_mask: allocation priority. Set __GFP_NOMEMALLOC if not for network Rx