From: Andrew Morton <akpm@linux-foundation.org>
To: Kyle Moffett <mrmacman_g4@mac.com>
Cc: Joe Perches <joe@perches.com>,
Randy Dunlap <randy.dunlap@oracle.com>,
jengelh@computergmbh.de, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Reduce stack used by lib/hexdump.c
Date: Wed, 5 Dec 2007 23:10:40 -0800 [thread overview]
Message-ID: <20071205231040.f6c9b40e.akpm@linux-foundation.org> (raw)
In-Reply-To: <831AEA99-3615-4015-9415-A4572D690095@mac.com>
On Thu, 6 Dec 2007 00:58:38 -0500 Kyle Moffett <mrmacman_g4@mac.com> wrote:
> On Dec 05, 2007, at 21:42:35, Joe Perches wrote:
> > On Wed, 2007-12-05 at 18:18 -0800, Randy Dunlap wrote:
> >> Joe Perches wrote:
> >>> Maybe just eliminate the 16 or 32 byte width option and force it
> >>> to only 16 byte widths.
> >> Have you checked users (callers)? I'm pretty sure that one of the
> >> callers wanted 32 and that's why it's there.
> >
> > I did. There is only 1 subsystem. That's easy to change.
> >
> > drivers/mtd/ubi/debug.c: print_hex_dump(KERN_DEBUG, "",
> > DUMP_PREFIX_OFFSET, 32, 1,
> > drivers/mtd/ubi/io.c: print_hex_dump(KERN_DEBUG, "",
> > DUMP_PREFIX_OFFSET, 32, 1,
> >
> > Long lines in the log file are not too easy to read anyway. Using
> > 16 byte dumps per line instead of 32 isn't painful.
> >
> > It gets rid of the allocation, reduces the argument count and makes
> > the kernel smaller. I think it's all good.
> >
> > Every current caller would have to change though.
>
> Alternatively, since print_hex_dump is not a performance-critical
> path (and usually indicates an error/debug condition), you could
> probably just make a static "hexdump_lock" spinlock and
> spin_lock_irqsave()/spin_unlock_irqrestore(). It would always nest
> inside any other lock (except during crash, where we break locks
> already for printk()), and I doubt any of the callers would notice
> the serialization since they're already serialized on the printk buffer.
>
Yup, that'd work.
next prev parent reply other threads:[~2007-12-06 7:11 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-29 18:08 [PATCH] Remove #define hex_asc from kernel.h, update lib/hexdump.c Joe Perches
2007-11-29 18:24 ` Randy Dunlap
2007-11-29 18:44 ` Joe Perches
2007-11-29 18:52 ` Randy Dunlap
2007-11-29 18:55 ` Joe Perches
2007-11-29 20:57 ` [PATCH] Reduce stack used by lib/hexdump.c Joe Perches
2007-11-29 21:02 ` Randy Dunlap
2007-11-29 21:07 ` Jan Engelhardt
2007-11-29 23:28 ` Joe Perches
2007-12-06 0:01 ` Andrew Morton
2007-12-06 2:10 ` Joe Perches
2007-12-06 2:18 ` Randy Dunlap
2007-12-06 2:42 ` Joe Perches
2007-12-06 5:58 ` Kyle Moffett
2007-12-06 7:10 ` Andrew Morton [this message]
2007-12-06 21:52 ` Joe Perches
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