lkml.org 
[lkml]   [2015]   [Apr]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 2/2] locking/rwsem: Use a return variable in rwsem_spin_on_owner()
From
Date
On Thu, 2015-04-09 at 12:43 -0700, Jason Low wrote:
> So that looks more similar to how the original code was where the
> rcu_read_lock() and rcu_read_unlock() was done inside the owner_running
> helper function (though without the CONFIG_DEBUG_PAGEALLOC), before
> commit 307bf9803f25 ("sched: Simplify mutex_spin_on_owner()") modified
> it to be done outside the loop.

I think this is why Linus was mentioning the CONFIG_PREEMPT_RCU case as
well, so taking and releasing the read lock in those cases in the loop
would actually hurt more.

Thanks,
Davidlohr



\
 
 \ /
  Last update: 2015-04-09 22:41    [W:0.212 / U:0.588 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site