From: Ingo Molnar <mingo@elte.hu>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Joerg Roedel <joerg.roedel@amd.com>,
linux-kernel@vger.kernel.org, mingo@redhat.com,
dwmw2@infradead.org, fujita.tomonori@lab.ntt.co.jp,
netdev@vger.kernel.org, iommu@lists.linux-foundation.org
Subject: Re: [PATCH 03/16] dma-debug: add hash functions for dma_debug_entries
Date: Wed, 14 Jan 2009 12:43:47 +0100 [thread overview]
Message-ID: <20090114114347.GG8625@elte.hu> (raw)
In-Reply-To: <20090113005118.82f5037b.akpm@linux-foundation.org>
* Andrew Morton <akpm@linux-foundation.org> wrote:
> On Fri, 9 Jan 2009 17:19:17 +0100 Joerg Roedel <joerg.roedel@amd.com> wrote:
>
> > +struct hash_bucket {
> > + struct list_head list;
> > + spinlock_t lock;
> > +} ____cacheline_aligned;
>
> __cacheline_aligned_in_smp.
>
> This all looks like an exotically large amount of code for a debug
> thingy?
this code checks the DMA usage of ~1 million lines of kernel code - all
the DMA using drivers. I think Joerg's feature is hugely relevant as DMA
scribbles are one of the hardest to debug kernel bugs: they can end up in
permanent data corruption or other hard to find bugs. In fact i think his
patchset is rather simple and even having 10 times as much debug code
would pay for its existence in the long run.
Ingo
next prev parent reply other threads:[~2009-01-14 11:45 UTC|newest]
Thread overview: 73+ 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 [this message]
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
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 03/16] dma-debug: add hash functions for dma_debug_entries Joerg Roedel
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