Find a file
Kenneth Graunke 7bb4ada8e0 iris: Bypass the BO cache when allocating buffers for aux map tables
When freeing a buffer, we may return a non-idle buffer to the cache,
which means we cannot unmap aux entries at that time.  Instead, we
defer unmapping the stale aux entry until we reuse a BO from the cache.

Unfortunately, this can lead to a recursive locking issue:

1. intel_aux_map_add_mapping wants to set up a new aux entry

   It takes the intel_aux_map_context::mutex lock, then calls:

   add_mapping -> get_aux_entry -> add_sub_table -> add_buffer ->
   intel_aux_map_buffer_alloc -> iris_bo_alloc

2. iris_bo_alloc tries to allocate a BO from the cache, doing:

   alloc_bo_from_cache -> intel_aux_map_unmap_range ->
   intel_aux_unmap_range

   ...which then tries to take the intel_aux_map_context::mutex lock.
   But it is already locked.

One solution would be to rework the aux map handling code to allocate
BOs without holding its lock, but that looks to be painful.  Another
is to make the lock recursive, but we try and avoid that.  A third
option wuold be to add a BO_ALLOC flag that makes alloc_bo_from_cache
skip any buffers with aux_map_address != 0 so we don't have to unmap,
making the less cache effective but fixing the recursive lock.

A fourth option is to simply bypass the BO cache altogether for the
buffers that hold the aux map itself.  Allocating new BOs for the aux
tables should be relatively rare, so there's probably not a lot of
benefit in using the BO cache.

Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/5191
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12420>
2021-08-23 13:28:22 -07:00
.gitlab/issue_templates issue_templates/Bug Report: Rename master branch to main 2021-05-05 12:20:11 -07:00
.gitlab-ci ci/freedreno: Move freedreno's deqp testing to suite support. 2021-08-17 20:00:49 +00:00
android AOSP: Add panfrost vulkan library suffix 2021-08-16 09:18:46 +00:00
bin python: drop python2 support 2021-08-14 21:44:32 +00:00
build-support configure: commit test files 2017-10-16 16:32:43 -07:00
docs tu: Enable VK_KHR_uniform_buffer_standard_layout 2021-08-23 18:30:22 +00:00
include dri: Reformat DRI context attribute #defines 2021-08-18 21:11:02 +00:00
src iris: Bypass the BO cache when allocating buffers for aux map tables 2021-08-23 13:28:22 -07:00
subprojects util: Perfetto SDK v15.0 2021-05-07 13:41:38 +00:00
.dir-locals.el dir-locals.el: Adds White Space support 2016-11-14 19:17:49 +02:00
.editorconfig editorconfig: Use 3-space tabs for .rst 2021-06-22 17:37:55 +00:00
.gitignore intel/tools: Add unit tests for assembler 2019-05-07 14:33:48 -07:00
.gitlab-ci.yml ci: enable CI for lima again 2021-08-17 11:22:59 +00:00
.mailmap mailmap: Add two more lines for Alyssa Rosenzweig 2021-07-12 23:45:34 +00:00
.travis.yml travis: Download XQuartz from GitHub. 2021-05-29 10:25:16 +00:00
meson.build meson: Check that bin/meson_get_version.py ran without an error 2021-08-17 15:18:03 -07:00
meson_options.txt meson: allow egl_native_platform to be specified 2021-07-21 23:12:58 +00:00
README.rst docs: promote #dri-devel on oftc over freenode 2021-05-24 09:21:48 +00:00
REVIEWERS Fix up leftover "state_trackers" references to "frontends" 2021-07-02 07:35:05 +00:00
VERSION VERSION: bump version for 21.3 development cycle 2021-07-14 10:22:12 -07:00

`Mesa <https://mesa3d.org>`_ - The 3D Graphics Library
======================================================


Source
------

This repository lives at https://gitlab.freedesktop.org/mesa/mesa.
Other repositories are likely forks, and code found there is not supported.


Build & install
---------------

You can find more information in our documentation (`docs/install.rst
<https://mesa3d.org/install.html>`_), but the recommended way is to use
Meson (`docs/meson.rst <https://mesa3d.org/meson.html>`_):

.. code-block:: sh

  $ mkdir build
  $ cd build
  $ meson ..
  $ sudo ninja install


Support
-------

Many Mesa devs hang on IRC; if you're not sure which channel is
appropriate, you should ask your question on `OFTC's #dri-devel
<irc://irc.oftc.net/dri-devel>`_, someone will redirect you if
necessary.
Remember that not everyone is in the same timezone as you, so it might
take a while before someone qualified sees your question.
To figure out who you're talking to, or which nick to ping for your
question, check out `Who's Who on IRC
<https://dri.freedesktop.org/wiki/WhosWho/>`_.

The next best option is to ask your question in an email to the
mailing lists: `mesa-dev\@lists.freedesktop.org
<https://lists.freedesktop.org/mailman/listinfo/mesa-dev>`_


Bug reports
-----------

If you think something isn't working properly, please file a bug report
(`docs/bugs.rst <https://mesa3d.org/bugs.html>`_).


Contributing
------------

Contributions are welcome, and step-by-step instructions can be found in our
documentation (`docs/submittingpatches.rst
<https://mesa3d.org/submittingpatches.html>`_).

Note that Mesa uses gitlab for patches submission, review and discussions.