On Thu, May 21, 2020 at 11:57:12AM +0200, Vlastimil Babka wrote: > On 5/20/20 9:26 PM, Roman Gushchin wrote: > > On Wed, May 20, 2020 at 02:25:22PM +0200, Vlastimil Babka wrote: > >> > >> However __mod_node_page_state() and mode_node_state() will now branch always. I > >> wonder if the "API clean" goal is worth it... > > > > You mean just adding a special write-side helper which will perform a conversion > > and put VM_WARN_ON_ONCE() into generic write-side helpers? > > What I mean is that maybe node/global helpers should assume page granularity, > and lruvec/memcg helpers do the check is they should convert from bytes to pages > when calling node/global helpers. Then there would be no extra branches in > node/global helpers. But maybe it's not worth saving those branches, dunno. The problem is with helpers like mod_lruvec_state(), which do modify both global and memcg-level counters. Also memcg- and global counters share idxes, so it will be confusing to have NR_SLAB_RECLAIMABLE in bytes on one level and in pages on the other. So, idk, maybe there is a better way of organizing these counters in a less complicated manner, but I've no ideas at the moment. But if you do, I'll appreciate it. Thanks!
