It have been a long road. Back in July 2014 I realized that network stack were hitting the kmem_cache/SLUB slowpath when freeing SKBs, but had no solution. In Dec 2014 I had implemented a solution called qmempool[1], that showed it was possible to improve this, but got rejected due to being a cache on top of kmem_cache. In July 2015 improvements to kmem_cache were proposed, and recently Oct 2015 my kmem_cache (SLAB+SLUB) patches for bulk alloc and free have been accepted into the AKPM quilt tree. This patchset is the first real use-case kmem_cache bulk alloc and free. And is joint work with Alexander Duyck while still at Red Hat. Using bulk free to avoid the SLUB slowpath shows the full potential. In this patchset it is realized in NAPI/softirq context. 1. During DMA TX completion bulk free is optimal and does not introduce any added latency. 2. bulk free of SKBs delay free'ed due to IRQ context in net_tx_action softirq completion queue. Using bulk alloc is showing minor improvements for SLUB(+0.9%), but a very slight slowdown for SLAB(-0.1%). [1] http://thread.gmane.org/gmane.linux.network/342347/focus=126138 This patchset is based on net-next (commit 26440c835), BUT I've applied several patches from AKPMs MM-tree. Cherrypick some commits from MMOTM tree on branch/tag mmotm-2015-10-06-16-30 from git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git (Below commit IDs are obviously not stable) Pickup my own MM-changes: b0aa3e95ce82 ("slub: mark the dangling ifdef #else of CONFIG_SLUB_DEBUG") 114a2b37847c ("slab: implement bulking for SLAB allocator") 606397476e8b ("slub: support for bulk free with SLUB freelists") ee29cd6a570c ("slub: optimize bulk slowpath free by detached freelist") 491c6e0ca89d ("slub-optimize-bulk-slowpath-free-by-detached-freelist-fix") Pickup slab.h changes: d9a47e0b776b ("compiler.h: add support for function attribute assume_aligned") 1c3a5c789b4f ("slab.h: sprinkle __assume_aligned attributes") Wanted Kirill A. Shutemov's changes as they change virt_to_head_page(), had to apply patches manually from http://ozlabs.org/~akpm/mmotm/ (stamp-2015-10-20-16-33) as AKPM made several small fixes. --- Jesper Dangaard Brouer (4): net: bulk free infrastructure for NAPI context, use napi_consume_skb net: bulk free SKBs that were delay free'ed due to IRQ context ixgbe: bulk free SKBs during TX completion cleanup cycle net: bulk alloc and reuse of SKBs in NAPI context drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 6 + include/linux/skbuff.h | 4 + net/core/dev.c | 9 ++ net/core/skbuff.c | 122 +++++++++++++++++++++++-- 4 files changed, 127 insertions(+), 14 deletions(-) -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>