Marc Merlin reported many order-1 allocations failures in TX path on its wireless setup, that dont make any sense with MTU=1500 network, and non SG capable hardware. Turns out part of the problem comes from pskb_expand_head() not using ksize() to get exact head size given by kmalloc(). Doing the same thing than __alloc_skb() allows more tailroom in skb and can prevent future reallocations. As a bonus, struct skb_shared_info becomes cache line aligned. Reported-by: Marc MERLIN <marc@xxxxxxxxxxx> Tested-by: Marc MERLIN <marc@xxxxxxxxxxx> Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx> --- net/core/skbuff.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index baf8d28..e598400 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -952,9 +952,11 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, goto adjust_others; } - data = kmalloc(size + sizeof(struct skb_shared_info), gfp_mask); + data = kmalloc(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)), + gfp_mask); if (!data) goto nodata; + size = SKB_WITH_OVERHEAD(ksize(data)); /* Copy only real data... and, alas, header. This should be * optimized for the cases when header is void. -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
