linux-scsi.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Leon Romanovsky <leon@kernel.org>
To: Bob Pearson <rpearsonhpe@gmail.com>,
	". Bart Van Assche" <bvanassche@acm.org>
Cc: zyjzyj2000@gmail.com, jgg@ziepe.ca, linux-rdma@vger.kernel.org,
	matsuda-daisuke@fujitsu.com, shinichiro.kawasaki@wdc.com,
	linux-scsi@vger.kernel.org, Zhu Yanjun <yanjun.zhu@intel.com>,
	Zhu Yanjun <yanjun.zhu@linux.dev>
Subject: Re: [PATCH 1/1] Revert "RDMA/rxe: Add workqueue support for rxe tasks"
Date: Sun, 1 Oct 2023 09:30:48 +0300	[thread overview]
Message-ID: <20231001063048.GA6351@unreal> (raw)
In-Reply-To: <6d9aaf05-c4cb-2b8e-c3dd-899e0360b6a1@gmail.com>

On Wed, Sep 27, 2023 at 11:51:12AM -0500, Bob Pearson wrote:
> On 9/26/23 15:24, Bart Van Assche wrote:
> > On 9/26/23 11:34, Bob Pearson wrote:
> >> I am working to try to reproduce the KASAN warning. Unfortunately,
> >> so far I am not able to see it in Ubuntu + Linus' kernel (as you described) on metal. The config file is different but copies the CONFIG_KASAN_xxx exactly as yours. With KASAN enabled it hangs on every iteration of srp/002 but without a KASAN warning. I am now building an openSuSE VM for qemu and will see if that causes the warning.
> > 
> > Hi Bob,
> > 
> > Did you try to understand the report that I shared? My conclusion from
> > the report is that when using tasklets rxe_completer() only runs after
> > rxe_requester() has finished and also that when using work queues that
> > rxe_completer() may run concurrently with rxe_requester(). This patch
> > seems to fix all issues that I ran into with the rdma_rxe workqueue
> > patch (I have not tried to verify the performance implications of this
> > patch):
> > 
> > diff --git a/drivers/infiniband/sw/rxe/rxe_task.c b/drivers/infiniband/sw/rxe/rxe_task.c
> > index 1501120d4f52..6cd5d5a7a316 100644
> > --- a/drivers/infiniband/sw/rxe/rxe_task.c
> > +++ b/drivers/infiniband/sw/rxe/rxe_task.c
> > @@ -10,7 +10,7 @@ static struct workqueue_struct *rxe_wq;
> > 
> >  int rxe_alloc_wq(void)
> >  {
> > -       rxe_wq = alloc_workqueue("rxe_wq", WQ_UNBOUND, WQ_MAX_ACTIVE);
> > +       rxe_wq = alloc_workqueue("rxe_wq", WQ_UNBOUND, 1);
> >         if (!rxe_wq)
> >                 return -ENOMEM;
> > 
> > Thanks,
> > 
> > Bart.

<...>

> Nevertheless this is a good hint since it seems to imply that there is a race between the requester and
> completer which is certainly possible.

Bob, Bart

Can you please send this change as a formal patch?
As we prefer workqueue with bad performance implementation over tasklets.

Thanks

> 
> Bob
> 
> 

  reply	other threads:[~2023-10-01  6:30 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-22 16:32 [PATCH 1/1] Revert "RDMA/rxe: Add workqueue support for rxe tasks" Zhu Yanjun
2023-09-22 16:42 ` Bart Van Assche
2023-09-26  9:43   ` Leon Romanovsky
2023-09-26  9:43 ` Leon Romanovsky
2023-09-26 14:06   ` Leon Romanovsky
2023-09-26 17:05     ` Bart Van Assche
2023-09-26 18:34       ` Bob Pearson
2023-09-26 20:24         ` Bart Van Assche
2023-09-27  0:08           ` Rain River
2023-09-27 16:36           ` Bob Pearson
2023-09-27 16:51           ` Bob Pearson
2023-10-01  6:30             ` Leon Romanovsky [this message]
2023-10-04 17:44               ` Bart Van Assche
2023-10-04  3:41           ` Zhu Yanjun
2023-10-04 17:43             ` Bart Van Assche
2023-10-04 18:38               ` Jason Gunthorpe
2023-10-05  9:25                 ` Zhu Yanjun
2023-10-05 14:21                   ` Jason Gunthorpe
2023-10-05 14:50                     ` Bart Van Assche
2023-10-05 15:56                       ` Jason Gunthorpe
2023-10-06 15:58                         ` Bob Pearson
2023-10-07  0:35                           ` Zhu Yanjun
2023-10-08 16:01                       ` Zhu Yanjun
2023-10-08 17:09                         ` Leon Romanovsky
2023-10-10  4:53                         ` Daisuke Matsuda (Fujitsu)
2023-10-10 16:09                           ` Jason Gunthorpe
2023-10-10 21:29                             ` Bart Van Assche
2023-10-11 15:51                               ` Jason Gunthorpe
2023-10-11 20:14                                 ` Bart Van Assche
2023-10-11 23:12                                   ` Jason Gunthorpe
2023-10-12 11:49                                     ` Zhu Yanjun
2023-10-12 15:38                                       ` Bob Pearson

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=20231001063048.GA6351@unreal \
    --to=leon@kernel.org \
    --cc=bvanassche@acm.org \
    --cc=jgg@ziepe.ca \
    --cc=linux-rdma@vger.kernel.org \
    --cc=linux-scsi@vger.kernel.org \
    --cc=matsuda-daisuke@fujitsu.com \
    --cc=rpearsonhpe@gmail.com \
    --cc=shinichiro.kawasaki@wdc.com \
    --cc=yanjun.zhu@intel.com \
    --cc=yanjun.zhu@linux.dev \
    --cc=zyjzyj2000@gmail.com \
    /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).