From 400dfd3ae899849b27d398ca7894e1b44430887f Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 17 Oct 2013 16:27:07 -0700 Subject: [PATCH] net: refactor sk_page_frag_refill() While working on virtio_net new allocation strategy to increase payload/truesize ratio, we found that refactoring sk_page_frag_refill() was needed. This patch splits sk_page_frag_refill() into two parts, adding skb_page_frag_refill() which can be used without a socket. While we are at it, add a minimum frag size of 32 for sk_page_frag_refill() Michael will either use netdev_alloc_frag() from softirq context, or skb_page_frag_refill() from process context in refill_work() (GFP_KERNEL allocations) Signed-off-by: Eric Dumazet Cc: Michael Dalton Signed-off-by: David S. Miller --- include/linux/skbuff.h | 2 ++ net/core/sock.c | 27 +++++++++++++++++++++++---- 2 files changed, 25 insertions(+), 4 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 1cd32f96055..ba74474836c 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2062,6 +2062,8 @@ static inline void skb_frag_set_page(struct sk_buff *skb, int f, __skb_frag_set_page(&skb_shinfo(skb)->frags[f], page); } +bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t prio); + /** * skb_frag_dma_map - maps a paged fragment via the DMA API * @dev: the device to map the fragment to diff --git a/net/core/sock.c b/net/core/sock.c index fd6afa26747..440afdca1e8 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1847,7 +1847,17 @@ EXPORT_SYMBOL(sock_alloc_send_skb); /* On 32bit arches, an skb frag is limited to 2^15 */ #define SKB_FRAG_PAGE_ORDER get_order(32768) -bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag) +/** + * skb_page_frag_refill - check that a page_frag contains enough room + * @sz: minimum size of the fragment we want to get + * @pfrag: pointer to page_frag + * @prio: priority for memory allocation + * + * Note: While this allocator tries to use high order pages, there is + * no guarantee that allocations succeed. Therefore, @sz MUST be + * less or equal than PAGE_SIZE. + */ +bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t prio) { int order; @@ -1856,16 +1866,16 @@ bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag) pfrag->offset = 0; return true; } - if (pfrag->offset < pfrag->size) + if (pfrag->offset + sz <= pfrag->size) return true; put_page(pfrag->page); } /* We restrict high order allocations to users that can afford to wait */ - order = (sk->sk_allocation & __GFP_WAIT) ? SKB_FRAG_PAGE_ORDER : 0; + order = (prio & __GFP_WAIT) ? SKB_FRAG_PAGE_ORDER : 0; do { - gfp_t gfp = sk->sk_allocation; + gfp_t gfp = prio; if (order) gfp |= __GFP_COMP | __GFP_NOWARN; @@ -1877,6 +1887,15 @@ bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag) } } while (--order >= 0); + return false; +} +EXPORT_SYMBOL(skb_page_frag_refill); + +bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag) +{ + if (likely(skb_page_frag_refill(32U, pfrag, sk->sk_allocation))) + return true; + sk_enter_memory_pressure(sk); sk_stream_moderate_sndbuf(sk); return false; -- 2.43.2