From: "David S. Miller" <davem@redhat.com>
To: anton@samba.org
Cc: davidm@hpl.hp.com, davidm@napali.hpl.hp.com,
manfred@colorfullife.com, axboe@suse.de,
linux-kernel@vger.kernel.org
Subject: Re: problem with blk_queue_bounce_limit()
Date: Sun, 15 Jun 2003 01:18:12 -0700 (PDT) [thread overview]
Message-ID: <20030615.011812.10301547.davem@redhat.com> (raw)
In-Reply-To: <20030615080442.GF31148@krispykreme>
From: Anton Blanchard <anton@samba.org>
Date: Sun, 15 Jun 2003 18:04:42 +1000
To make the best use of the IOMMU we would want to have it filled with
addresses (to have the best chance that we will find an existing
mapping). And for zero copy stuff it could be all over RAM.
In effect we are looking at a mapping from 512GB -> 3GB. (assuming the
top 1GB of PCI addresses are for PCI IO and memory)
We have this same problem with huge files in the page cache.
Maybe you should use a trie.
Because that data structure will expand wrt. actual use.
I bet the management (especially the shared memory refcount bump)
will outweight the costs saved unless your hardware is really stupid.
But judging by the e1000/ppc64 issue, your hardware is stupid and thus
maybe it's worthwhile for you to continue to pursue this idea :)
next prev parent reply other threads:[~2003-06-15 8:09 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-06-05 6:42 problem with blk_queue_bounce_limit() David Mosberger
2003-06-05 7:20 ` David S. Miller
2003-06-06 6:42 ` David Mosberger
2003-06-06 6:45 ` David S. Miller
2003-06-06 6:54 ` David Mosberger
2003-06-06 7:08 ` David S. Miller
2003-06-06 6:52 ` David S. Miller
2003-06-06 7:19 ` David Mosberger
2003-06-06 7:32 ` David S. Miller
2003-06-06 7:44 ` Christoph Hellwig
2003-06-06 7:43 ` David S. Miller
2003-06-06 7:51 ` Christoph Hellwig
2003-06-06 20:13 ` David Mosberger
2003-06-07 6:44 ` David S. Miller
2003-06-07 7:05 ` David Mosberger
2003-06-07 7:11 ` David S. Miller
2003-06-10 20:01 ` David Mosberger
2003-06-12 6:47 ` David S. Miller
2003-06-15 7:06 ` Anton Blanchard
2003-06-15 7:11 ` David S. Miller
2003-06-15 8:04 ` Anton Blanchard
2003-06-15 8:18 ` David S. Miller [this message]
2003-06-07 7:20 ` David Mosberger
2003-06-07 7:19 ` David S. Miller
2003-06-07 9:44 ` Russell King
2003-06-07 9:47 ` David S. Miller
2003-06-07 13:23 ` Christoph Hellwig
2003-06-10 20:24 ` David Mosberger
-- strict thread matches above, loose matches on Subject: below --
2003-06-06 18:06 James Bottomley
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