From: "David S. Miller" <davem@redhat.com>
To: adam@yggdrasil.com
Cc: sp@scali.com, linux-kernel@vger.kernel.org
Subject: Re: Does kmalloc always return address below 4GB?
Date: Tue, 05 Mar 2002 17:13:33 -0800 (PST) [thread overview]
Message-ID: <20020305.171333.72710637.davem@redhat.com> (raw)
In-Reply-To: <200203051708.JAA05742@adam.yggdrasil.com>
In-Reply-To: <200203051708.JAA05742@adam.yggdrasil.com>
From: "Adam J. Richter" <adam@yggdrasil.com>
Date: Tue, 5 Mar 2002 09:08:20 -0800
Steffen Persvold writes:
>I know pci_map_single (and _sg) will
>use bounce buffers on platforms without an IOMMU [...]
For a moment I thought that must be the point that I
was missing, but I don't see any such bounce buffer support
in linux-2.5.6-pre2/include/asm-i386/pci.h or arch/i386/kernel/pci-dma.c.
I do not see how this is currently implemented on x86 systems with >4GB
of RAM.
You won't get HIGHMEM pages in your driver unless you are using
2.5.x and tell the scsi layer you are capable to DMA to/from
HIGHMEM pages.
Similarly for networking drivers, and setting NETIF_F_HIGHDMA in
the net device feature flags.
next prev parent reply other threads:[~2002-03-06 1:16 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-03-05 17:08 Does kmalloc always return address below 4GB? Adam J. Richter
2002-03-06 1:13 ` David S. Miller [this message]
-- strict thread matches above, loose matches on Subject: below --
2002-03-06 2:28 Adam J. Richter
2002-03-05 16:39 Adam J. Richter
2002-03-05 17:00 ` Gerd Knorr
2002-03-06 7:22 ` David S. Miller
2002-03-05 21:57 ` Steffen Persvold
2002-03-05 14:43 Adam J. Richter
2002-03-05 15:15 ` David S. Miller
2002-03-05 11:52 Adam J. Richter
2002-03-05 11:59 ` David S. Miller
2002-03-05 11:12 Adam J. Richter
2002-03-05 11:16 ` David S. Miller
2002-03-05 15:43 ` Steffen Persvold
2002-03-05 15:47 ` David S. Miller
2002-03-05 16:44 ` David Mosberger
2002-03-06 1:09 ` David S. Miller
2002-03-06 1:31 ` David Mosberger
2002-03-06 1:52 ` David S. Miller
2002-03-06 2:04 ` David Mosberger
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20020305.171333.72710637.davem@redhat.com \
--to=davem@redhat.com \
--cc=adam@yggdrasil.com \
--cc=linux-kernel@vger.kernel.org \
--cc=sp@scali.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox