From: Roland Dreier <rdreier@cisco.com>
To: Grant Grundler <grundler@parisc-linux.org>
Cc: akepner@sgi.com, Jesse Barnes <jbarnes@virtuousgeek.org>,
Jes Sorensen <jes@sgi.com>,
Randy Dunlap <randy.dunlap@oracle.com>,
David Miller <davem@davemloft.net>,
linux-kernel@vger.kernel.org,
James Bottomley <James.Bottomley@steeleye.com>
Subject: Re: [PATCH 0/4] allow drivers to flush in-flight DMA
Date: Wed, 26 Sep 2007 12:29:12 -0700 [thread overview]
Message-ID: <adabqbpted3.fsf@cisco.com> (raw)
In-Reply-To: <20070926064950.GB30430@colo.lackof.org> (Grant Grundler's message of "Wed, 26 Sep 2007 00:49:50 -0600")
> Can we define this API to provide the same semantics as the memory
> that dma_alloc_coherent() returns?
No, definitely not. The property of the mapping here is all about
ordering with respect to other DMAs (from the same device) and nothing
to do with coherency between the CPU's and device's view of the memory.
> Sorry - this feels like a "color of the shed" argument, but isn't
> this about DMA ordering attribute?
> "dmaflush" is an action and not an attribute to me.
I guess I don't love the "dmaflush" name, but the property of these
mappings is exactly that DMA into one of these mappings also performs
the action of flushing other in-flight DMAs. However I guess your
point is a good one: the effect really desired is that DMAs to these
mappings become visible strictly after earlier DMAs, and we don't care
exactly how the effect is obtained.
No good idea of a better name though.
- R.
next prev parent reply other threads:[~2007-09-26 19:29 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-25 23:58 [PATCH 0/4] allow drivers to flush in-flight DMA akepner
2007-09-26 6:49 ` Grant Grundler
2007-09-26 15:17 ` Jesse Barnes
2007-09-26 19:29 ` Roland Dreier [this message]
2007-09-28 0:27 ` akepner
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=adabqbpted3.fsf@cisco.com \
--to=rdreier@cisco.com \
--cc=James.Bottomley@steeleye.com \
--cc=akepner@sgi.com \
--cc=davem@davemloft.net \
--cc=grundler@parisc-linux.org \
--cc=jbarnes@virtuousgeek.org \
--cc=jes@sgi.com \
--cc=linux-kernel@vger.kernel.org \
--cc=randy.dunlap@oracle.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