lkml.org 
[lkml]   [2009]   [Aug]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 13/12] ksm: fix munlock during exit_mmap deadlock
On Tue, Aug 25, 2009 at 06:49:09PM +0100, Hugh Dickins wrote:
> Sorry, I just don't get it. How does down_read here help?
> Perhaps you thought ksm.c had down_write of mmap_sem in all cases?
>
> No, and I don't think we want to change its down_reads to down_writes.

Looking ksm.c it should have been down_write indeed...

> Nor do we want to change your down_read here to down_write, that will
> just reintroduce the OOM deadlock that 9/12 was about solving.

I'm not sure anymore I get what this fix is about... mm_users is
allowed to go to 0. If mm_users is allowed to go to 0, it's up to ksm
to check inside its inner loops that mm_users is 0 and bail
out. Bailing out it will unblock exit so that exit_mmap can run. What
exactly is the unfixable issue?


\
 
 \ /
  Last update: 2009-08-25 20:17    [W:0.081 / U:0.420 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site