Messages in this thread |  | | Date | Fri, 14 Feb 2014 16:30:34 +0100 | From | Nicholas Mc Guire <> | Subject | Re: [PATCH RT 4/5] allow preemption in mem_cgroup_move_account_page_stat |
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On Fri, 14 Feb 2014, Sebastian Andrzej Siewior wrote:
> * Sebastian Andrzej Siewior | 2014-02-14 14:17:05 [+0100]: > > >Now, that I look at it again. Isn't it more efficient to keep preemption > >disabled for this very short time instead instead of invoking > >migrate_disable() which includes preempt_disable()/enable() and a few > >more opcodes??? > >Therefore, I drop it again. > > I think doing the same for the 1/5 of this series since it also disables > migration for a handfull of asm opcodes. > yup - nice run in the wrong direction :) those short pushdowns make no sense - should have looked at that first... the execution length/complexity (notably worst case on migrate_enable()) is actually very high compared to a preempt_enable.
thx! hofrat
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