On Fri, Aug 31, 2012 at 11:36:07AM +0200, Sasha Levin wrote: > On 08/30/2012 03:38 PM, Michael S. Tsirkin wrote: > >> +static unsigned int indirect_alloc_thresh = 16; > > Why 16? Please make is MAX_SG + 1 this makes some sense. > > Wouldn't MAX_SG mean we always allocate from the cache? Isn't the memory waste > too big in this case?
Sorry. I really meant MAX_SKB_FRAGS + 1. MAX_SKB_FRAGS is 17 so gets us threshold of 18. It is less than the size of an skb+shinfo itself so - does it look too big to you? Also why do you think 16 is not too big but 18 is? If there's a reason then I am fine with 16 too but then please put it in code comment near where the value is set. Yes this means virtio net always allocates from cache but this is a good thing, isn't it? Gets us more consistent performance. -- MST -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
