From: george anzinger <george@mvista.com>
To: "David C. Hansen" <dave@sr71.net>
Cc: Alexander Viro <viro@math.psu.edu>,
linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@transmeta.com>
Subject: Re: [LART] pc_keyb.c changes
Date: Fri, 30 Nov 2001 17:04:58 -0800 [thread overview]
Message-ID: <3C082CBA.B66BF30F@mvista.com> (raw)
In-Reply-To: <Pine.GSO.4.21.0111300252030.13367-100000@weyl.math.psu.edu> <3C07FB73.9030708@sr71.net>
"David C. Hansen" wrote:
>
> Alexander Viro wrote:
>
> > Could the person who switched from BKL to spin_lock_irqsave() in
> > pc_keyb.c please share whatever the hell he had been smoking? Free clue:
> > disabling interrupts for long intervals to improve scalability is right up
> > there with fighting for peace and fucking for virginity.
> As I slowly raise my hand to take, um credit....
>
> This is definitely one of the drivers I to take a second look at, now
> that I know about the BKL being held for block and char device opens.
> Do you have any ideas how else to do this safely since aux_count is
> referenced during an interrupt?
>
Um, staying as far away from that bit of source as possible, I will
offer:
It depends on how it is referenced. If it is just a counter, you may be
able to just make it atomic. If it needs to "stick" for a little
longer, then consider if there are many readers and only a few writers,
in which case look at the read/write_lockirq code, however, this does
have the down side of irq off. BKL did not protect against interrupts,
so one wonders if the irq bit is needed at all.
--
George george@mvista.com
High-res-timers: http://sourceforge.net/projects/high-res-timers/
Real time sched: http://sourceforge.net/projects/rtsched/
next prev parent reply other threads:[~2001-12-01 1:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-11-30 8:25 [LART] pc_keyb.c changes Alexander Viro
2001-11-30 9:04 ` Alexander Viro
2001-11-30 21:34 ` David C. Hansen
2001-12-01 1:04 ` george anzinger [this message]
-- strict thread matches above, loose matches on Subject: below --
2001-12-01 2:05 David C. Hansen
2001-12-01 9:56 ` Alan Cox
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