From: David Miller <davem@davemloft.net>
To: ebiederm@xmission.com
Cc: benh@kernel.crashing.org, suresh.b.siddha@intel.com,
matthew@wil.cx, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org, grundler@parisc-linux.org,
mingo@elte.hu, tglx@linutronix.de, jgarzik@pobox.com,
linux-ide@vger.kernel.org, jbarnes@virtuousgeek.org,
rdunlap@xenotime.net, mtk.manpages@gmail.com
Subject: Re: Multiple MSI, take 3
Date: Sun, 13 Jul 2008 20:19:06 -0700 (PDT) [thread overview]
Message-ID: <20080713.201906.60811176.davem@davemloft.net> (raw)
In-Reply-To: <m1ej5x1at3.fsf@frodo.ebiederm.org>
From: ebiederm@xmission.com (Eric W. Biederman)
Date: Sun, 13 Jul 2008 19:03:52 -0700
> At the very least you are left with the problem of allocating multiple
> contiguous destinations. Which has the potential to create
> fragmentation on all supported platforms.
I don't think this is a very real concern. With 256 MSI slots
available per domain, at least on sparc64, no real case can cause
problems.
And even so, drivers can and should fall back when allocations fail
anyways.
That's what drivers, at least the ones I have written, do even for
MSI-X. For example, the NIU driver scales back the number of
MSI-X vectors it askes for if the original request cannot be
satisfied.
> My honest opinion is that the should have deprecated multi-msi after
> the introduction of the msi-x specification.
I don't think this would have materially influenced what happened with
AHCI at all.
next prev parent reply other threads:[~2008-07-14 3:19 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-11 0:57 Multiple MSI, take 3 Matthew Wilcox
2008-07-11 0:59 ` [PATCH] PCI MSI: Replace 'type' with 'is_msix' Matthew Wilcox
2008-07-11 0:59 ` [PATCH] PCI: Add support for multiple MSI Matthew Wilcox
2008-07-11 8:28 ` Hidetoshi Seto
2008-07-11 9:45 ` Matthew Wilcox
2008-07-12 3:45 ` Benjamin Herrenschmidt
2008-07-11 1:00 ` [PATCH] Rewrite MSI-HOWTO Matthew Wilcox
2008-09-26 6:42 ` Grant Grundler
2008-07-11 1:00 ` [PATCH] AHCI: Request multiple MSIs Matthew Wilcox
2008-07-11 1:00 ` [PATCH] x86-64: Support for " Matthew Wilcox
2008-07-11 4:50 ` Kenji Kaneshige
2008-07-11 8:50 ` Matthew Wilcox
2008-07-14 1:08 ` Kenji Kaneshige
2008-07-11 10:06 ` Multiple MSI, take 3 Eric W. Biederman
2008-07-11 10:23 ` Matthew Wilcox
2008-07-11 10:32 ` David Miller
2008-07-11 10:41 ` Matthew Wilcox
2008-07-11 11:05 ` Eric W. Biederman
2008-07-11 11:34 ` Eric W. Biederman
2008-07-11 12:17 ` Matthew Wilcox
2008-07-11 15:10 ` Matthew Wilcox
2008-07-11 21:59 ` Suresh Siddha
2008-07-11 22:59 ` Eric W. Biederman
2008-07-11 23:15 ` Suresh Siddha
2008-07-11 23:59 ` Eric W. Biederman
2008-07-12 3:52 ` Benjamin Herrenschmidt
2008-07-12 4:41 ` Eric W. Biederman
2008-07-12 7:36 ` Benjamin Herrenschmidt
2008-07-13 22:30 ` Eric W. Biederman
2008-07-13 22:44 ` Benjamin Herrenschmidt
2008-07-13 23:29 ` Eric W. Biederman
2008-07-14 0:17 ` Benjamin Herrenschmidt
2008-07-14 0:44 ` David Miller
2008-07-14 2:03 ` Eric W. Biederman
2008-07-14 3:19 ` David Miller [this message]
2008-09-26 5:30 ` Jike Song
2008-09-27 19:04 ` Matthew Wilcox
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