From: Thomas Gleixner <tglx@linutronix.de>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: Juri Lelli <juri.lelli@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
dri-devel <dri-devel@lists.freedesktop.org>,
linux-mips@vger.kernel.org, Ben Segall <bsegall@google.com>,
Max Filippov <jcmvbkbc@gmail.com>, Guo Ren <guoren@kernel.org>,
sparclinux@vger.kernel.org, Vincent Chen <deanbo422@gmail.com>,
Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
"open list:GENERIC INCLUDE/A..." <linux-arch@vger.kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Herbert Xu <herbert@gondor.apana.org.au>,
Michael Ellerman <mpe@ellerman.id.au>, X86 ML <x86@kernel.org>,
Russell King <linux@armlinux.org.uk>,
linux-csky@vger.kernel.org, David Airlie <airlied@linux.ie>,
Mel Gorman <mgorman@suse.de>,
arcml <linux-snps-arc@lists.infradead.org>,
linux-xtensa@linux-xtensa.org, Paul McKenney <paulmck@kernel.org>,
intel-gfx <intel-gfx@lists.freedesktop.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
Steven Rostedt <rostedt@goodmis.org>,
Linus Torvalds <torvalds@linuxfoundation.org>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Chris Zankel <chris@zankel.net>, Michal Simek <monstr@monstr.eu>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Nick Hu <nickhu@andestech.com>, Linux-MM <linux-mm@kvack.org>,
Vineet Gupta <vgupta@synopsys.com>,
LKML <linux-kernel@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>, Paul Mackerras <paulus@samba.org>,
Andrew Morton <akpm@linux-foundation.org>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
Greentime Hu <green.hu@gmail.com>
Subject: Re: [patch RFC 00/15] mm/highmem: Provide a preemptible variant of kmap_atomic & friends
Date: Sun, 20 Sep 2020 19:24:49 +0200 [thread overview]
Message-ID: <87h7rscqe6.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20200920082353.GG438822@phenom.ffwll.local>
On Sun, Sep 20 2020 at 10:23, Daniel Vetter wrote:
> On Sun, Sep 20, 2020 at 08:23:26AM +0200, Thomas Gleixner wrote:
>> On Sat, Sep 19 2020 at 12:37, Daniel Vetter wrote:
>> > On Sat, Sep 19, 2020 at 12:35 PM Daniel Vetter <daniel@ffwll.ch> wrote:
>> >> I think it should be the case, but I want to double check: Will
>> >> copy_*_user be allowed within a kmap_temporary section? This would
>> >> allow us to ditch an absolute pile of slowpaths.
>> >
>> > (coffee just kicked in) copy_*_user is ofc allowed, but if you hit a
>> > page fault you get a short read/write. This looks like it would remove
>> > the need to handle these in a slowpath, since page faults can now be
>> > served in this new kmap_temporary sections. But this sounds too good
>> > to be true, so I'm wondering what I'm missing.
>>
>> In principle we could allow pagefaults, but not with the currently
>> proposed interface which can be called from any context. Obviously if
>> called from atomic context it can't handle user page faults.
>
> Yeah that's clear, but does the implemention need to disable pagefaults
> unconditionally?
As I wrote in the other reply it's not required and the final interface
will neither disable preemption nor pagefaults (except for the atomic
wrapper around it).
Thanks,
tglx
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2020-09-21 7:35 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-19 9:17 [patch RFC 00/15] mm/highmem: Provide a preemptible variant of kmap_atomic & friends Thomas Gleixner
2020-09-19 9:17 ` [patch RFC 01/15] mm/highmem: Un-EXPORT __kmap_atomic_idx() Thomas Gleixner
2020-09-19 9:17 ` [patch RFC 02/15] highmem: Provide generic variant of kmap_atomic* Thomas Gleixner
2020-09-19 9:17 ` [patch RFC 03/15] x86/mm/highmem: Use generic kmap atomic implementation Thomas Gleixner
2020-09-19 9:17 ` [patch RFC 04/15] arc/mm/highmem: " Thomas Gleixner
2020-09-19 9:17 ` [patch RFC 05/15] ARM: highmem: Switch to generic kmap atomic Thomas Gleixner
2020-09-19 9:17 ` [patch RFC 06/15] csky/mm/highmem: " Thomas Gleixner
2020-09-23 0:05 ` Guo Ren
2020-09-19 9:17 ` [patch RFC 07/15] microblaze/mm/highmem: " Thomas Gleixner
2020-09-19 9:17 ` [patch RFC 08/15] mips/mm/highmem: " Thomas Gleixner
2020-09-19 9:18 ` [patch RFC 09/15] nds32/mm/highmem: " Thomas Gleixner
2020-09-19 9:18 ` [patch RFC 10/15] powerpc/mm/highmem: " Thomas Gleixner
2020-09-19 9:18 ` [patch RFC 11/15] sparc/mm/highmem: " Thomas Gleixner
2020-09-19 9:18 ` [patch RFC 12/15] xtensa/mm/highmem: " Thomas Gleixner
2020-09-19 9:18 ` [patch RFC 13/15] mm/highmem: Remove the old kmap_atomic cruft Thomas Gleixner
2020-09-19 9:18 ` [patch RFC 14/15] sched: highmem: Store temporary kmaps in task struct Thomas Gleixner
2020-09-19 9:18 ` [patch RFC 15/15] mm/highmem: Provide kmap_temporary* Thomas Gleixner
2020-09-19 10:35 ` [patch RFC 00/15] mm/highmem: Provide a preemptible variant of kmap_atomic & friends Daniel Vetter
2020-09-19 10:37 ` Daniel Vetter
2020-09-20 6:23 ` Thomas Gleixner
2020-09-20 8:23 ` Daniel Vetter
2020-09-20 17:24 ` Thomas Gleixner [this message]
2020-09-19 17:18 ` Linus Torvalds
2020-09-19 17:39 ` Matthew Wilcox
2020-09-19 19:13 ` Linus Torvalds
2020-09-21 19:58 ` Ira Weiny
2020-09-20 6:41 ` Thomas Gleixner
2020-09-20 8:49 ` Thomas Gleixner
2020-09-20 16:57 ` Linus Torvalds
2020-09-20 17:40 ` Thomas Gleixner
2020-09-20 17:42 ` Linus Torvalds
2020-09-20 17:58 ` Linus Torvalds
2020-09-21 7:39 ` Thomas Gleixner
2020-09-21 16:24 ` Linus Torvalds
2020-09-21 19:27 ` Thomas Gleixner
2020-09-23 8:40 ` peterz
2020-09-23 13:35 ` Thomas Gleixner
2020-09-23 15:52 ` Steven Rostedt
2020-09-23 20:55 ` Thomas Gleixner
2020-09-23 21:12 ` Steven Rostedt
2020-09-24 6:57 ` Thomas Gleixner
2020-09-24 12:32 ` Steven Rostedt
2020-09-24 12:42 ` Peter Zijlstra
2020-09-24 13:51 ` Steven Rostedt
2020-09-24 13:58 ` Peter Zijlstra
2020-09-24 17:55 ` Thomas Gleixner
2020-09-24 18:58 ` Steven Rostedt
2020-09-24 8:27 ` peterz
2020-09-24 19:36 ` Daniel Bristot de Oliveira
2020-09-23 10:19 ` peterz
2020-09-23 12:33 ` Thomas Gleixner
2020-09-23 14:33 ` Thomas Gleixner
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=87h7rscqe6.fsf@nanos.tec.linutronix.de \
--to=tglx@linutronix.de \
--cc=airlied@linux.ie \
--cc=akpm@linux-foundation.org \
--cc=ardb@kernel.org \
--cc=arnd@arndb.de \
--cc=bigeasy@linutronix.de \
--cc=bristot@redhat.com \
--cc=bsegall@google.com \
--cc=chris@zankel.net \
--cc=daniel@ffwll.ch \
--cc=davem@davemloft.net \
--cc=deanbo422@gmail.com \
--cc=dietmar.eggemann@arm.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=green.hu@gmail.com \
--cc=guoren@kernel.org \
--cc=herbert@gondor.apana.org.au \
--cc=intel-gfx@lists.freedesktop.org \
--cc=jcmvbkbc@gmail.com \
--cc=juri.lelli@redhat.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-csky@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mips@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-snps-arc@lists.infradead.org \
--cc=linux-xtensa@linux-xtensa.org \
--cc=linux@armlinux.org.uk \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mgorman@suse.de \
--cc=monstr@monstr.eu \
--cc=mpe@ellerman.id.au \
--cc=nickhu@andestech.com \
--cc=paulmck@kernel.org \
--cc=paulus@samba.org \
--cc=peterz@infradead.org \
--cc=rodrigo.vivi@intel.com \
--cc=rostedt@goodmis.org \
--cc=sparclinux@vger.kernel.org \
--cc=torvalds@linuxfoundation.org \
--cc=tsbogend@alpha.franken.de \
--cc=vgupta@synopsys.com \
--cc=vincent.guittot@linaro.org \
--cc=will@kernel.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).