From: Kalle Valo <kvalo@qca.qualcomm.com>
To: Michal Kazior <michal.kazior@tieto.com>
Cc: <ath10k@lists.infradead.org>, <linux-wireless@vger.kernel.org>
Subject: Re: [PATCH v2 4/4] ath10k: fix issues on non-preemptible systems
Date: Tue, 27 Aug 2013 10:06:13 +0300 [thread overview]
Message-ID: <87ioyrmx3u.fsf@kamboji.qca.qualcomm.com> (raw)
In-Reply-To: <1377507205-5386-5-git-send-email-michal.kazior@tieto.com> (Michal Kazior's message of "Mon, 26 Aug 2013 10:53:25 +0200")
Michal Kazior <michal.kazior@tieto.com> writes:
> Workers may not call into a sleepable function
> (e.g. mutex_lock). Since ath10k workers can run
> for a very long time it is necessary to explicitly
> allow process rescheduling in case there's no
> preemption.
>
> This fixes some issues with system freezes, hangs,
> watchdogs being triggered, userspace being
> unresponsive on slow host machines under heavy
> load.
I consider this more as a workaround as a real fix. Would NAPI be a
proper fix for issues like this?
NAPI support was removed from mac80211 six months ago, but I guess we
could try to get it back if we have a good reason:
http://marc.info/?l=linux-wireless&m=136204135907491
> --- a/drivers/net/wireless/ath/ath10k/htt_rx.c
> +++ b/drivers/net/wireless/ath/ath10k/htt_rx.c
> @@ -1229,6 +1229,10 @@ static void ath10k_htt_rx_work(struct work_struct *work)
> break;
>
> ath10k_htt_rx_process_skb(htt->ar, skb);
> +
> +#ifndef CONFIG_PREEMPT
> + cond_resched();
> +#endif
Why the #ifndef? Why should we not call cond_resched() when PREEMPT is
enabled? Does something negative happen then?
--
Kalle Valo
next prev parent reply other threads:[~2013-08-27 7:06 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-21 6:34 [PATCH 0/3] ath10k: fixes Michal Kazior
2013-08-21 6:34 ` [PATCH 1/3] ath10k: make the workqueue multithreaded Michal Kazior
2013-08-21 6:34 ` [PATCH 2/3] ath10k: move htt rx processing to worker Michal Kazior
2013-08-21 6:34 ` [PATCH 3/3] ath10k: fix issues on non-preemptible systems Michal Kazior
2013-08-22 10:05 ` [PATCH 0/3] ath10k: fixes Michal Kazior
2013-08-26 8:53 ` [PATCH v2 0/4] " Michal Kazior
2013-08-26 8:53 ` [PATCH v2 1/4] ath10k: synchronize tx/rx reporting to mac80211 Michal Kazior
2013-08-28 4:23 ` Kalle Valo
2013-08-28 10:54 ` Michal Kazior
2013-08-28 11:04 ` Kalle Valo
2013-08-26 8:53 ` [PATCH v2 2/4] ath10k: make the workqueue multithreaded Michal Kazior
2013-08-26 8:53 ` [PATCH v2 3/4] ath10k: move htt rx processing to worker Michal Kazior
2013-08-26 8:53 ` [PATCH v2 4/4] ath10k: fix issues on non-preemptible systems Michal Kazior
2013-08-27 7:06 ` Kalle Valo [this message]
2013-08-27 7:30 ` Michal Kazior
2013-08-28 4:02 ` Kalle Valo
2013-08-28 13:16 ` Michal Kazior
2013-08-26 20:20 ` [PATCH v2 0/4] ath10k: fixes Luis R. Rodriguez
2013-08-27 5:42 ` Michal Kazior
2013-08-27 7:59 ` Luis R. Rodriguez
2013-08-27 6:57 ` Kalle Valo
2013-08-27 8:01 ` Luis R. Rodriguez
2013-08-28 3:53 ` Kalle Valo
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=87ioyrmx3u.fsf@kamboji.qca.qualcomm.com \
--to=kvalo@qca.qualcomm.com \
--cc=ath10k@lists.infradead.org \
--cc=linux-wireless@vger.kernel.org \
--cc=michal.kazior@tieto.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).