From: David Miller <davem@davemloft.net>
To: hpa@zytor.com
Cc: torvalds@linux-foundation.org, bhutchings@solarflare.com,
tglx@linutronix.de, mingo@redhat.com, netdev@vger.kernel.org,
linux-net-drivers@solarflare.com, x86@kernel.org
Subject: Re: [PATCH 2/3] x86_64: Define 128-bit memory-mapped I/O operations
Date: Tue, 21 Aug 2012 21:14:27 -0700 (PDT) [thread overview]
Message-ID: <20120821.211427.1832042852041589162.davem@davemloft.net> (raw)
In-Reply-To: <5034591E.3040908@zytor.com>
From: "H. Peter Anvin" <hpa@zytor.com>
Date: Tue, 21 Aug 2012 20:59:26 -0700
> kernel_fpu_end() would still have to re-enable preemption (and
> preemption would have to check the work flag), but that should be cheap.
>
> We could allow the FPU in the kernel to have preemption, if we allocated
> space for two xstates per thread instead of one. That is, however, a
> fair hunk of memory.
Once you have done the first FPU save for the sake of the kernel, you
can minimize what you save for any deeper nesting because the kernel
only cares about a very limited part of that FPU state not the whole
1K thing.
Those bits you can save by hand with a bunch of explicit stores of the
XMM registers, or something like that.
next prev parent reply other threads:[~2012-08-22 4:14 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-22 1:17 [PATCH 0/3] x86_64, sfc: 128-bit memory-mapped I/O Ben Hutchings
2012-08-22 1:20 ` [PATCH 1/3] x86_64: Define 128-bit types for kernel code only Ben Hutchings
2012-08-22 1:23 ` [PATCH 2/3] x86_64: Define 128-bit memory-mapped I/O operations Ben Hutchings
2012-08-22 1:37 ` H. Peter Anvin
2012-08-22 2:04 ` Ben Hutchings
2012-08-22 2:34 ` David Miller
2012-08-22 3:24 ` H. Peter Anvin
2012-08-22 3:29 ` David Miller
2012-08-22 3:49 ` H. Peter Anvin
2012-08-22 3:52 ` Linus Torvalds
2012-08-22 3:59 ` H. Peter Anvin
2012-08-22 4:14 ` David Miller [this message]
2012-08-22 21:14 ` David Miller
2012-08-22 21:28 ` Linus Torvalds
2012-08-22 21:38 ` David Miller
2012-08-22 4:35 ` Linus Torvalds
2012-08-22 5:00 ` David Miller
2012-08-22 14:06 ` Linus Torvalds
2012-08-22 4:42 ` Linus Torvalds
2012-08-22 13:26 ` Ben Hutchings
2012-08-22 14:20 ` Linus Torvalds
2012-08-22 14:24 ` Ben Hutchings
2012-08-22 14:30 ` Benjamin LaHaise
2012-08-22 14:58 ` Ben Hutchings
2012-08-22 15:13 ` H. Peter Anvin
2012-08-22 15:27 ` David Laight
2012-08-22 15:49 ` H. Peter Anvin
2012-08-22 15:51 ` Ben Hutchings
2012-08-22 15:54 ` H. Peter Anvin
2012-08-22 16:44 ` Ben Hutchings
2012-08-22 16:49 ` H. Peter Anvin
2012-08-22 16:55 ` Linus Torvalds
2012-08-22 17:09 ` Ben Hutchings
2012-08-22 17:12 ` H. Peter Anvin
2012-08-22 17:27 ` Ben Hutchings
2012-08-22 17:54 ` Linus Torvalds
2012-08-22 18:11 ` Ben Hutchings
2012-08-22 18:18 ` H. Peter Anvin
2012-08-22 18:28 ` Linus Torvalds
2012-08-22 19:01 ` Ben Hutchings
2012-08-22 17:26 ` Linus Torvalds
2012-08-22 16:51 ` Linus Torvalds
2012-08-22 16:59 ` H. Peter Anvin
2012-08-22 15:51 ` H. Peter Anvin
2012-08-22 14:50 ` Linus Torvalds
2012-08-22 14:56 ` Linus Torvalds
2012-08-22 15:05 ` David Laight
2012-08-22 15:16 ` Linus Torvalds
2012-08-22 15:41 ` Ben Hutchings
2012-08-22 14:42 ` David Laight
2012-08-22 1:26 ` [PATCH 3/3] sfc: Use __raw_writeo() to perform TX descriptor push where possible Ben Hutchings
2012-08-22 1:38 ` [PATCH 0/3] x86_64, sfc: 128-bit memory-mapped I/O H. Peter Anvin
2012-08-22 1:43 ` Ben Hutchings
2012-08-22 1:59 ` H. Peter Anvin
2012-08-22 2:10 ` Ben Hutchings
2012-08-22 2:31 ` H. Peter Anvin
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=20120821.211427.1832042852041589162.davem@davemloft.net \
--to=davem@davemloft.net \
--cc=bhutchings@solarflare.com \
--cc=hpa@zytor.com \
--cc=linux-net-drivers@solarflare.com \
--cc=mingo@redhat.com \
--cc=netdev@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--cc=x86@kernel.org \
/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;
as well as URLs for NNTP newsgroup(s).