From: "Nicholas Piggin" <npiggin@gmail.com>
To: "Christophe Leroy" <christophe.leroy@csgroup.eu>,
"Jordan Niethe" <jniethe5@gmail.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH 04/17] powerpc/qspinlock: convert atomic operations to assembly
Date: Thu, 10 Nov 2022 21:48:54 +1000 [thread overview]
Message-ID: <CO8LCA89WZYL.3APIMVZTFJ2QT@bobo> (raw)
In-Reply-To: <9226e7ca-c74b-845b-d10b-9928449a9489@csgroup.eu>
On Thu Nov 10, 2022 at 6:36 PM AEST, Christophe Leroy wrote:
>
>
> Le 10/11/2022 à 01:39, Jordan Niethe a écrit :
> >> +static __always_inline int trylock_clear_tail_cpu(struct qspinlock *lock, u32 old)
> >> {
> >> - int newval = _Q_LOCKED_VAL;
> >> -
> >> - if (atomic_cmpxchg_acquire(&lock->val, val, newval) == val)
> >> + u32 new = _Q_LOCKED_VAL;
> >> + u32 prev;
> >> +
> >> + BUG_ON(old & _Q_LOCKED_VAL);
> >
> > The BUG_ON() could have been introduced in an earlier patch I think.
>
> Can we avoid the BUG_ON() at all and replace by a WARN_ON ?
Lock has gone wrong here. Critical sections not working means data
corruption and little prospect of continuing to run.
Thanks,
Nick
next prev parent reply other threads:[~2022-11-10 11:50 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-28 6:31 [PATCH 00/17] powerpc: alternate queued spinlock implementation Nicholas Piggin
2022-07-28 6:31 ` [PATCH 01/17] powerpc/qspinlock: powerpc qspinlock implementation Nicholas Piggin
2022-08-10 1:52 ` Jordan NIethe
2022-08-10 6:48 ` Christophe Leroy
2022-11-10 0:35 ` Jordan Niethe
2022-11-10 6:37 ` Christophe Leroy
2022-11-10 11:44 ` Nicholas Piggin
2022-11-10 9:09 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 1a/17] powerpc/qspinlock: Prepare qspinlock code Nicholas Piggin
2022-07-28 6:31 ` [PATCH 02/17] powerpc/qspinlock: add mcs queueing for contended waiters Nicholas Piggin
2022-08-10 2:28 ` Jordan NIethe
2022-11-10 0:36 ` Jordan Niethe
2022-11-10 9:21 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 03/17] powerpc/qspinlock: use a half-word store to unlock to avoid larx/stcx Nicholas Piggin
2022-08-10 3:28 ` Jordan Niethe
2022-11-10 0:39 ` Jordan Niethe
2022-11-10 9:25 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 04/17] powerpc/qspinlock: convert atomic operations to assembly Nicholas Piggin
2022-08-10 3:54 ` Jordan Niethe
2022-11-10 0:39 ` Jordan Niethe
2022-11-10 8:36 ` Christophe Leroy
2022-11-10 11:48 ` Nicholas Piggin [this message]
2022-11-10 9:40 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 05/17] powerpc/qspinlock: allow new waiters to steal the lock before queueing Nicholas Piggin
2022-08-10 4:31 ` Jordan Niethe
2022-11-10 0:40 ` Jordan Niethe
2022-11-10 10:54 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 06/17] powerpc/qspinlock: theft prevention to control latency Nicholas Piggin
2022-08-10 5:51 ` Jordan Niethe
2022-11-10 0:40 ` Jordan Niethe
2022-11-10 10:57 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 07/17] powerpc/qspinlock: store owner CPU in lock word Nicholas Piggin
2022-08-12 0:50 ` Jordan Niethe
2022-11-10 0:40 ` Jordan Niethe
2022-11-10 10:59 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 08/17] powerpc/qspinlock: paravirt yield to lock owner Nicholas Piggin
2022-08-12 2:01 ` Jordan Niethe
2022-11-10 0:41 ` Jordan Niethe
2022-11-10 11:13 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 09/17] powerpc/qspinlock: implement option to yield to previous node Nicholas Piggin
2022-08-12 2:07 ` Jordan Niethe
2022-11-10 0:41 ` Jordan Niethe
2022-11-10 11:14 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 10/17] powerpc/qspinlock: allow stealing when head of queue yields Nicholas Piggin
2022-08-12 4:06 ` Jordan Niethe
2022-11-10 0:42 ` Jordan Niethe
2022-11-10 11:22 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 11/17] powerpc/qspinlock: allow propagation of yield CPU down the queue Nicholas Piggin
2022-08-12 4:17 ` Jordan Niethe
2022-10-06 17:27 ` Laurent Dufour
2022-11-10 0:42 ` Jordan Niethe
2022-11-10 11:25 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 12/17] powerpc/qspinlock: add ability to prod new queue head CPU Nicholas Piggin
2022-08-12 4:22 ` Jordan Niethe
2022-11-10 0:42 ` Jordan Niethe
2022-11-10 11:32 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 13/17] powerpc/qspinlock: trylock and initial lock attempt may steal Nicholas Piggin
2022-08-12 4:32 ` Jordan Niethe
2022-11-10 0:43 ` Jordan Niethe
2022-11-10 11:35 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 14/17] powerpc/qspinlock: use spin_begin/end API Nicholas Piggin
2022-08-12 4:36 ` Jordan Niethe
2022-11-10 0:43 ` Jordan Niethe
2022-11-10 11:36 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 15/17] powerpc/qspinlock: reduce remote node steal spins Nicholas Piggin
2022-08-12 4:43 ` Jordan Niethe
2022-11-10 0:43 ` Jordan Niethe
2022-11-10 11:37 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 16/17] powerpc/qspinlock: allow indefinite spinning on a preempted owner Nicholas Piggin
2022-08-12 4:49 ` Jordan Niethe
2022-09-22 15:02 ` Laurent Dufour
2022-09-23 8:16 ` Nicholas Piggin
2022-11-10 0:44 ` Jordan Niethe
2022-11-10 11:38 ` Nicholas Piggin
2022-07-28 6:31 ` [PATCH 17/17] powerpc/qspinlock: provide accounting and options for sleepy locks Nicholas Piggin
2022-08-15 1:11 ` Jordan Niethe
2022-11-10 0:44 ` Jordan Niethe
2022-11-10 11:41 ` Nicholas Piggin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CO8LCA89WZYL.3APIMVZTFJ2QT@bobo \
--to=npiggin@gmail.com \
--cc=christophe.leroy@csgroup.eu \
--cc=jniethe5@gmail.com \
--cc=linuxppc-dev@lists.ozlabs.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).