From: Ben Widawsky <ben@bwidawsk.net>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: intel-gfx <intel-gfx@lists.freedesktop.org>,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org
Subject: Re: [Intel-gfx] [PATCH 01/13] drm/i915: fall through pwrite_gtt_slow to the shmem slow path
Date: Sun, 20 Nov 2011 19:09:18 -0800 [thread overview]
Message-ID: <20111120190918.2b138476@bwidawsk.net> (raw)
In-Reply-To: <1320606840-21132-2-git-send-email-daniel.vetter@ffwll.ch>
On Sun, 6 Nov 2011 20:13:48 +0100
Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> The gtt_pwrite slowpath grabs the userspace memory with
> get_user_pages. This will not work for non-page backed memory, like a
> gtt mmapped gem object. Hence fall throuh to the shmem paths if we hit
> -EFAULT in the gtt paths.
>
> Now the shmem paths have exactly the same problem, but this way we
> only need to rearrange the code in one write path.
>
> v2: v1 accidentaly falls back to shmem pwrite for phys objects. Fixed.
>
> Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
It would be nice if there was some way to notify users that pwriting a
gtt mmapped address can be really damn slow. That's also the one
behavior change this patch introduces. It's possible that some SW was
expecting to get a, "fast path" and would deal with the -EFAULT if it
didn't get it.
Presumably subsequent patches in this series fix this up further, so
instead of figuring out all the failure conditions pwrite can cause,
let's just go with
Acked-by: Ben Widawsky <ben@bwidawsk.net>
next prev parent reply other threads:[~2011-11-21 3:09 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-06 19:13 [PATCH 00/13] pwrite/pread rework Daniel Vetter
2011-11-06 19:13 ` [PATCH 01/13] drm/i915: fall through pwrite_gtt_slow to the shmem slow path Daniel Vetter
2011-11-21 3:09 ` Ben Widawsky [this message]
2011-11-21 10:20 ` [Intel-gfx] " Chris Wilson
2011-11-06 19:13 ` [PATCH 02/13] drm/i915: rewrite shmem_pwrite_slow to use copy_from_user Daniel Vetter
2011-11-21 5:56 ` [Intel-gfx] " Ben Widawsky
2011-11-21 16:02 ` Daniel Vetter
2011-11-21 17:55 ` Ben Widawsky
2011-11-21 18:43 ` Ben Widawsky
2011-11-06 19:13 ` [PATCH 03/13] drm/i915: rewrite shmem_pread_slow to use copy_to_user Daniel Vetter
2011-11-06 19:13 ` [PATCH 04/13] drm/i915: merge shmem_pwrite slow&fast-path Daniel Vetter
2011-11-06 19:13 ` [PATCH 05/13] drm/i915: merge shmem_pread slow&fast-path Daniel Vetter
2011-11-06 19:13 ` [PATCH 06/13] drm: add helper to clflush a virtual address range Daniel Vetter
2011-11-21 19:46 ` [Intel-gfx] " Ben Widawsky
2011-11-06 19:13 ` [PATCH 07/13] drm/i915: move clflushing into shmem_pread Daniel Vetter
2011-11-06 19:13 ` [PATCH 08/13] drm/i915: kill ranged cpu read domain support Daniel Vetter
2011-11-06 19:13 ` [PATCH 09/13] drm/i915: don't use gtt_pwrite on LLC cached objects Daniel Vetter
2011-11-06 21:16 ` Chris Wilson
2011-11-06 22:19 ` Daniel Vetter
2011-11-06 19:13 ` [PATCH 10/13] drm/i915: don't call shmem_read_mapping unnecessarily Daniel Vetter
2011-11-06 19:13 ` [PATCH 11/13] mm: extend prefault helpers to fault in more than PAGE_SIZE Daniel Vetter
2011-11-06 22:24 ` Chris Wilson
2011-11-06 19:13 ` [PATCH 12/13] drm/i915: drop gtt slowpath Daniel Vetter
2011-11-06 19:14 ` [PATCH 13/13] drm/i915: don't clobber userspace memory before commiting to the pread Daniel Vetter
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=20111120190918.2b138476@bwidawsk.net \
--to=ben@bwidawsk.net \
--cc=daniel.vetter@ffwll.ch \
--cc=dri-devel@lists.freedesktop.org \
--cc=intel-gfx@lists.freedesktop.org \
--cc=linux-kernel@vger.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