From: Joerg Roedel <joro@8bytes.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Joerg Roedel <joerg.roedel@amd.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
iommu@lists.linux-foundation.org, mingo@redhat.com
Subject: Re: [PATCH 08/16] dma-debug: add core checking functions
Date: Sun, 11 Jan 2009 08:57:52 +0100 [thread overview]
Message-ID: <20090111075752.GI9466@8bytes.org> (raw)
In-Reply-To: <20090110231127.GK17917@elte.hu>
On Sun, Jan 11, 2009 at 12:11:27AM +0100, Ingo Molnar wrote:
>
> * Joerg Roedel <joerg.roedel@amd.com> wrote:
>
> > +#define err_printk(dev, format, arg...) do { \
> > + error_count += 1; \
> > + if (show_all_errors || show_num_errors > 0) { \
> > + WARN(1, "%s %s: " format, \
> > + dev_driver_string(dev), \
> > + dev_name(dev) , ## arg); \
> > + } \
> > + if (!show_all_errors && show_num_errors > 0) \
> > + show_num_errors -= 1; \
>
> Note that the arithmetics here is SMP-unsafe: we only hold the hash bucket
> so if two errors hit at once on two CPUs then the error tracking variables
> can be accessed at once.
>
> I'd suggest a simple global lock for this error case (taken inside the
> hash bucket lock), to be on the safe side.
>
> Also, please dont use a macro for this - printk details can be passed in
> to helper inlines/functions too.
Yeah, this is not SMP-safe, I know. But debugfs does not support
atomic_t so I made the variables u32. But at least a race condition has
not a too bad impact. What may habben is that error_count misses a error
or the show_num_errors become negative.
But if we really want to avoid this I think its better to add atomic_t
support to debugfs. What do you think?
Joerg
next prev parent reply other threads:[~2009-01-11 7:58 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-09 16:19 [PATCH 0/16] DMA-API debugging facility v2 Joerg Roedel
2009-01-09 16:19 ` [PATCH 01/16] dma-debug: add Kconfig entry Joerg Roedel
2009-01-09 20:12 ` Randy Dunlap
2009-01-09 16:19 ` [PATCH 02/16] dma-debug: add header file and core data structures Joerg Roedel
2009-01-11 6:25 ` FUJITA Tomonori
2009-01-09 16:19 ` [PATCH 03/16] dma-debug: add hash functions for dma_debug_entries Joerg Roedel
2009-01-09 17:55 ` Evgeniy Polyakov
2009-01-09 18:14 ` Joerg Roedel
2009-01-09 18:23 ` Evgeniy Polyakov
2009-01-09 18:40 ` Joerg Roedel
2009-01-13 8:51 ` Andrew Morton
2009-01-13 8:59 ` David Woodhouse
2009-01-14 11:43 ` Ingo Molnar
2009-01-14 17:39 ` Andrew Morton
2009-01-14 17:43 ` Ingo Molnar
2009-01-14 17:48 ` Ingo Molnar
2009-01-15 3:44 ` FUJITA Tomonori
2009-01-14 17:48 ` David Woodhouse
2009-01-14 17:51 ` Joerg Roedel
2009-01-09 16:19 ` [PATCH 04/16] dma-debug: add allocator code Joerg Roedel
2009-01-10 23:43 ` Ingo Molnar
2009-01-09 16:19 ` [PATCH 05/16] dma-debug: add initialization code Joerg Roedel
2009-01-09 17:58 ` Evgeniy Polyakov
2009-01-09 18:17 ` Joerg Roedel
2009-01-09 16:19 ` [PATCH 06/16] dma-debug: add kernel command line parameters Joerg Roedel
2009-01-09 16:19 ` [PATCH 07/16] dma-debug: add debugfs interface Joerg Roedel
2009-01-10 23:08 ` Ingo Molnar
2009-01-11 7:52 ` Joerg Roedel
2009-01-14 15:22 ` Joerg Roedel
2009-01-10 23:15 ` Ingo Molnar
2009-01-09 16:19 ` [PATCH 08/16] dma-debug: add core checking functions Joerg Roedel
2009-01-10 23:11 ` Ingo Molnar
2009-01-11 7:57 ` Joerg Roedel [this message]
2009-01-11 8:34 ` Joerg Roedel
2009-01-14 11:44 ` Joerg Roedel
2009-01-14 11:48 ` Ingo Molnar
2009-01-10 23:12 ` Ingo Molnar
2009-01-11 7:54 ` Joerg Roedel
2009-01-10 23:13 ` Ingo Molnar
2009-01-09 16:19 ` [PATCH 09/16] dma-debug: add checking for map/unmap_single Joerg Roedel
2009-01-09 16:19 ` [PATCH 10/16] dma-debug: add add checking for map/unmap_sg Joerg Roedel
2009-01-09 18:08 ` Evgeniy Polyakov
2009-01-09 18:11 ` Joerg Roedel
2009-01-09 16:19 ` [PATCH 11/16] dma-debug: add checking for [alloc|free]_coherent Joerg Roedel
2009-01-11 6:25 ` FUJITA Tomonori
2009-01-11 6:30 ` FUJITA Tomonori
2009-01-11 7:59 ` Joerg Roedel
2009-01-09 16:19 ` [PATCH 12/16] dma-debug: add checks for sync_single_* Joerg Roedel
2009-01-09 16:19 ` [PATCH 13/16] dma-debug: add checks for sync_single_range_* Joerg Roedel
2009-01-09 16:19 ` [PATCH 14/16] dma-debug: add checks for sync_single_sg_* Joerg Roedel
2009-01-10 23:46 ` Ingo Molnar
2009-01-11 8:00 ` Joerg Roedel
2009-01-09 16:19 ` [PATCH 15/16] dma-debug: x86 architecture bindings Joerg Roedel
2009-01-10 23:04 ` Ingo Molnar
2009-01-10 23:48 ` Ingo Molnar
2009-01-11 6:25 ` FUJITA Tomonori
2009-01-11 8:08 ` Joerg Roedel
2009-01-09 16:19 ` [PATCH 16/16] dma-debug: Documentation update Joerg Roedel
2009-01-09 21:24 ` [PATCH 0/16] DMA-API debugging facility v2 Michael Chan
2009-01-09 22:33 ` Joerg Roedel
2009-01-09 22:37 ` Joerg Roedel
2009-01-11 6:25 ` FUJITA Tomonori
2009-01-10 23:54 ` Ingo Molnar
2009-01-11 8:11 ` Joerg Roedel
2009-02-05 22:52 ` David Woodhouse
2009-02-06 2:05 ` Chris Wright
2009-02-06 7:56 ` David Woodhouse
2009-02-06 16:08 ` Chris Wright
2009-02-06 18:20 ` Chris Wright
2009-02-12 14:48 ` Joerg Roedel
2009-02-06 2:27 ` Chris Wright
2009-02-12 15:20 ` Joerg Roedel
2009-01-19 14:46 [PATCH 0/16] DMA-API debugging facility v3 Joerg Roedel
2009-01-19 14:46 ` [PATCH 08/16] dma-debug: add core checking functions Joerg Roedel
2009-02-05 21:07 ` David Woodhouse
2009-02-12 14:49 ` Joerg Roedel
2009-02-13 19:48 ` Jesse Brandeburg
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