On 3/12/21 4:01 PM, Christoph Lameter wrote: > On Thu, 11 Mar 2021, akpm@xxxxxxxxxxxxxxxxxxxx wrote: > >> This patch introduces two counters to maintain the actual number of >> partial objects dynamically instead of iterating the partial page lists >> with list_lock held. > > Well these counters have to be maintained in the fast paths of the > allocator. This approach increases the cache footprint, increases the > complexity of fastpaths even more. It reduces performance (which may not > be that visible in benchmarks that can keep the entire processing logic in > l1 or so) and causes a future maintenance headache. > > The only reason to use this counter that was given is to retrieve the > current number of partial objects via sysfs. This is not a critical > operation and the use of that sysfs file could be avoided. > > Or we can simply remove the ability to retrieve the number of partial > objects from sysfs? > Not only sysfs, /proc/slabinfo is another user to calculate the "active_objs", I'm afraid it's hard to change the ABI of this commonly-used interface.
