On Thu 13-10-22 20:50:48, Zhongkun He wrote:
Hi Michal
Could we try to change the MPOL_F_SHARED flag to MPOL_F_STATIC to
mark static mempolicy which cannot be freed, and mpol_needs_cond_ref
can use MPOL_F_STATIC to avoid freeing the static mempolicy.
Wouldn't it make more sense to get rid of a different treatment and
treat all memory policies the same way?
I found a case, not sure if it makes sense. If there is no policy
in task->mempolicy, the use of atomic_{inc,dec} can be skiped
according to MPOL_F_STATIC. Atomic_{inc,dec} in hot path may reduces
performance.
I would start with a simple conversion and do any potential
optimizations on top of that based on actual numbers. Maybe we can
special case default_policy to avoid reference counting a default (no
policy case). A simple check for pol == &default_policy should be
negligible.
Got it, thanks for your reply and suggestions.
