lkml.org 
[lkml]   [2014]   [May]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] vmalloc: use rcu list iterator to reduce vmap_area_lock contention
On Thu, 29 May 2014 15:22:34 +0900 Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:

> Richard Yao reported a month ago that his system have a trouble
> with vmap_area_lock contention during performance analysis
> by /proc/meminfo. Andrew asked why his analysis checks /proc/meminfo
> stressfully, but he didn't answer it.
>
> https://lkml.org/lkml/2014/4/10/416
>
> Although I'm not sure that this is right usage or not, there is a solution
> reducing vmap_area_lock contention with no side-effect. That is just
> to use rcu list iterator in get_vmalloc_info(). This function only needs
> values on vmap_area structure, so we don't need to grab a spinlock.

The mixture of rcu protection and spinlock protection for
vmap_area_list is pretty confusing. Are you able to describe the
overall design here? When and why do we use one versus the other?




\
 
 \ /
  Last update: 2014-05-29 22:41    [W:0.074 / U:0.108 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site