Messages in this thread | | | From | <> | Subject | RE: Bug 71331 - mlock yields processor to lower priority process | Date | Fri, 21 Mar 2014 14:50:34 +0000 |
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________________________________________ From: Mike Galbraith [umgwanakikbuti@gmail.com] Sent: Friday, March 21, 2014 9:41 AM To: Davis, Bud @ SSG - Link Cc: oneukum@suse.de; artem_fetishev@epam.com; peterz@infradead.org; kosaki.motohiro@jp.fujitsu.com; linux-kernel@vger.kernel.org Subject: RE: Bug 71331 - mlock yields processor to lower priority process
On Fri, 2014-03-21 at 14:01 +0000, jimmie.davis@l-3com.com wrote:
> If you call mlock () from a SCHED_FIFO task, you expect it to return > when done. You don't expect it to block, and your task to be > pre-empted.
Say some of your pages are sitting in an nfs swapfile orbiting Neptune, how do they get home, and what should we do meanwhile?
-Mike
Two options.
#1. Return with a status value of EAGAIN.
or
#2. Don't return until you can do it.
If SCHED_FIFO is used, and mlock() is called, the intention of the user is very clear. Run this task until it is completed or it blocks (and until a bit ago, mlock() did not block).
SCHED_FIFO users don't care about fairness. They want the system to do what it is told.
regards, Bud Davis
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