On Tue, Oct 12, 2021 at 01:42:41PM +0300, Vasily Averin wrote: > On 08.10.2021 14:47, Vlastimil Babka wrote: > > On 10/8/21 11:24, Vasily Averin wrote: > >> __alloc_pages_bulk can call __count_zid_vm_events and zone_statistics > >> with nr_account = 0. > > > > But that's not a bug, right? Just an effective no-op that's not commonly > > happening, so is it worth the check? > > Why not? > > Yes, it's not a bug, it just makes the kernel a bit more efficient in a very unlikely case. At the cost of an additional branch in the likely case that may be mispredicted. > However, it looks strange and makes uninformed code reviewers like me worry about possible > problems inside the affected functions. No one else calls these functions from 0. > The accounting functions should still work with a 0 delta. -- Mel Gorman SUSE Labs
