Messages in this thread | | | Date | Tue, 12 Mar 2019 17:44:22 +0100 | From | Michal Hocko <> | Subject | Re: [PATCH] mm: compaction: some tracepoints should be defined only when CONFIG_COMPACTION is set |
| |
On Wed 13-03-19 00:29:57, Yafang Shao wrote: > On Wed, Mar 13, 2019 at 12:18 AM Michal Hocko <mhocko@kernel.org> wrote: > > > > On Sat 02-03-19 12:38:58, Yafang Shao wrote: > > > Only mm_compaction_isolate_{free, migrate}pages may be used when > > > CONFIG_COMPACTION is not set. > > > All others are used only when CONFIG_COMPACTION is set. > > > > Why is this an improvement? > > > > After this change, if CONFIG_COMPACTION is not set, the tracepoints > that only work when CONFIG_COMPACTION is set will not be exposed to > the usespace. > Without this change, they will always be expose in debugfs no matter > CONFIG_COMPACTION is set or not.
And this is exactly something that the changelog should mention. I wasn't aware that we do export tracepoints even when they are not used by any code path. This whole macro based programming is just a black magic. -- Michal Hocko SUSE Labs
| |