diff options
| author | Nicolai Hähnle <Nicolai.Haehnle@amd.com> | 2016-12-21 19:46:35 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-01-14 11:14:43 +0100 |
| commit | 200b1874401555e9b36010aa318e75cf57005f36 (patch) | |
| tree | 646203e67ab11ee6b22d52c439ae0e969f4b4a5f /tools/perf/scripts/python/call-graph-from-postgresql.py | |
| parent | 6baa5c60a97d7f1a37a4b5ab5fb3a450e56e8b06 (diff) | |
locking/ww_mutex: Notify waiters that have to back off while adding tasks to wait list
While adding our task as a waiter, detect if another task should back off
because of us.
With this patch, we establish the invariant that the wait list contains
at most one (sleeping) waiter with ww_ctx->acquired > 0, and this waiter
will be the first waiter with a context.
Since only waiters with ww_ctx->acquired > 0 have to back off, this allows
us to be much more economical with wakeups.
Signed-off-by: Nicolai Hähnle <Nicolai.Haehnle@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dri-devel@lists.freedesktop.org
Link: http://lkml.kernel.org/r/1482346000-9927-8-git-send-email-nhaehnle@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'tools/perf/scripts/python/call-graph-from-postgresql.py')
0 files changed, 0 insertions, 0 deletions