lkml.org 
[lkml]   [2018]   [Sep]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] locking/rwsem: Make owner store task pointer of last owning reader
On Mon, 10 Sep 2018, Waiman Long wrote:

>One major issue with a combined count/owner is that we may have to use
>cmpxchg for reader lock which will certainly impact reader-heavy
>workloads. I have also thought about ways to compress the task pointer
>address so that it can use fewer bits and leave the rests for reader
>count. It is probably doable on 64-bit systems, but likely not on 32-bit
>system given that there are less bits to play around.

Yeah we've discussed this before. As a cleanup it would obviously be good,
but I fear about raw performance loss when using cmpxchg instead of xadd.

Thanks,
Davidlohr

\
 
 \ /
  Last update: 2018-09-10 19:16    [W:0.057 / U:0.268 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site