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Tvrtko Ursulin d3f84c8b09 drm/i915/pmu: Fix PMU enable vs execlists tasklet race
Commit 99e48bf98d ("drm/i915: Lock out execlist tasklet while peeking
inside for busy-stats") added a tasklet_disable call in busy stats
enabling, but we failed to understand that the PMU enable callback runs
as an hard IRQ (IPI).

Consequence of this is that the PMU enable callback can interrupt the
execlists tasklet, and will then deadlock when it calls
intel_engine_stats_enable->tasklet_disable.

To fix this, I realized it is possible to move the engine stats enablement
and disablement to PMU event init and destroy hooks. This allows for much
simpler implementation since those hooks run in normal context (can
sleep).

v2: Extract engine_event_destroy. (Chris Wilson)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: 99e48bf98d ("drm/i915: Lock out execlist tasklet while peeking inside for busy-stats")
Testcase: igt/perf_pmu/enable-race-*
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180205093448.13877-1-tvrtko.ursulin@linux.intel.com
(cherry picked from commit b2f78cda26)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180213095747.2424-2-tvrtko.ursulin@linux.intel.com
2018-02-13 16:55:59 -08:00
Documentation KVM changes for 4.16 2018-02-10 13:16:35 -08:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
arch unify {de,}mangle_poll(), get rid of kernel-side POLL... 2018-02-11 14:37:22 -08:00
block vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
drivers drm/i915/pmu: Fix PMU enable vs execlists tasklet race 2018-02-13 16:55:59 -08:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
include unify {de,}mangle_poll(), get rid of kernel-side POLL... 2018-02-11 14:37:22 -08:00
init membarrier: Provide core serializing command, *_SYNC_CORE 2018-02-05 21:35:03 +01:00
ipc vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
kernel vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
lib Kbuild updates for v4.16 (2nd) 2018-02-09 19:32:41 -08:00
mm vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
net vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
samples sample/bpf: fix erspan metadata 2018-02-06 11:32:49 -05:00
scripts Kbuild updates for v4.16 (2nd) 2018-02-09 19:32:41 -08:00
security vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
sound vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-02-09 15:34:18 -08:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore scripts/package: snap-pkg target 2017-12-13 00:00:18 +09:00
.mailmap mailmap: update Mark Yao's email address 2018-01-04 16:45:09 -08:00
COPYING
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS KVM changes for 4.16 2018-02-10 13:16:35 -08:00
Makefile Linux 4.16-rc1 2018-02-11 15:04:29 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.