On Wed, 18 Apr 2007 09:17:19 +0300 (EEST) Pekka J Enberg <[EMAIL PROTECTED]> wrote:
> On Tue, 17 Apr 2007, Eric Dumazet wrote: > > This nr_pages should be in struct kmem_list3, not in struct kmem_cache, > > or else you defeat NUMA optimizations if touching a field in kmem_cache > > at kmem_getpages()/kmem_freepages() time. > > We already touch ->flags, ->gfpflags, and ->gfporder in kmem_getpages(). > Sorry for my ignorance, but how is this different? > Those fields are read. Thats OK, because several CPUS might share all those without problem. But modifying one field in kmem_cache would invalidate one cache line for all cpus that would have to reload it later. This is what we call "false sharing" or cache line ping pongs _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
