From: Jesper Dangaard Brouer <brouer@xxxxxxxxxx> Date: Fri, 23 Oct 2015 14:46:01 +0200 > 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) Logically I'm fine with this series, but as you mention there are dependencies that need to hit upstream before I can merge any of this stuff into my tree. I also think that patch #4 is a net-win, and also will expose the bulking code to more testing since it will be used more often. -- 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>