NetBSD Problem Report #55094
From ad@netbsd.org Sat Mar 21 17:09:57 2020
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for <gnats-bugs@gnats.NetBSD.org>; Sat, 21 Mar 2020 17:09:57 +0000 (UTC)
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Date: Sat, 21 Mar 2020 17:09:57 +0000 (UTC)
From: ad@netbsd.org
Reply-To: ad@netbsd.org
To: gnats-bugs@NetBSD.org
Subject: vax pmap needs locking adjustments
X-Send-Pr-Version: 3.95
>Number: 55094
>Category: port-vax
>Synopsis: vax pmap needs locking adjustments
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: ad
>State: closed
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Sat Mar 21 17:10:00 +0000 2020
>Closed-Date: Sat Mar 21 18:48:39 +0000 2020
>Last-Modified: Sat Mar 21 18:50:03 +0000 2020
>Originator: Andrew Doran
>Release: NetBSD 9.99.50
>Organization:
The NetBSD Project
>Environment:
n/a
>Description:
The vax pmap looks like it needs locking at the pmap level, to
protect against multi-threaded programs doing concurrent operations.
It probably works OK for pmap_kernel since there is PV list locking,
and you don't tend to get concurrent modifications to the same VA in
pmap_kernel.
>How-To-Repeat:
Code inspection.
>Fix:
Have a global pmap_lock. That would allow removal of the atomics
adjusting stats, and removal of pvtable_lock. Low maintainence
overhead and low runtime cost.
>Release-Note:
>Audit-Trail:
Responsible-Changed-From-To: port-vax-maintainer->ad
Responsible-Changed-By: ad@NetBSD.org
Responsible-Changed-When: Sat, 21 Mar 2020 17:10:55 +0000
Responsible-Changed-Why:
I like DEC equipment
State-Changed-From-To: open->closed
State-Changed-By: ad@NetBSD.org
State-Changed-When: Sat, 21 Mar 2020 18:48:39 +0000
State-Changed-Why:
fixed
From: "Andrew Doran" <ad@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc:
Subject: PR/55094 CVS commit: src/sys/arch/vax
Date: Sat, 21 Mar 2020 18:47:55 +0000
Module Name: src
Committed By: ad
Date: Sat Mar 21 18:47:54 UTC 2020
Modified Files:
src/sys/arch/vax/include: pmap.h
src/sys/arch/vax/vax: pmap.c
Log Message:
PR port-vax/55094: vax pmap needs locking adjustments
Make the adjustments noted in the PR and don't call uvm_wait() or do
WAITOK ever - UVM takes care of that.
To generate a diff of this commit:
cvs rdiff -u -r1.81 -r1.82 src/sys/arch/vax/include/pmap.h
cvs rdiff -u -r1.189 -r1.190 src/sys/arch/vax/vax/pmap.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
>Unformatted:
(Contact us)
$NetBSD: query-full-pr,v 1.46 2020/01/03 16:35:01 leot Exp $
$NetBSD: gnats_config.sh,v 1.9 2014/08/02 14:16:04 spz Exp $
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