/* * sw_sync abstraction * * Copyright 2015-2016 Collabora Ltd. * * Based on the implementation from the Android Open Source Project, * * Copyright 2013 Google, Inc * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. */ #ifndef SELFTESTS_SW_SYNC_H #define SELFTESTS_SW_SYNC_H /* * sw_sync is mainly intended for testing and should not be compiled into * production kernels */ int sw_sync_timeline_create(void); int sw_sync_timeline_is_valid(int fd); int sw_sync_timeline_inc(int fd, unsigned int count); void sw_sync_timeline_destroy(int fd); int sw_sync_fence_create(int fd, const char *name, unsigned int value); int sw_sync_fence_is_valid(int fd); void sw_sync_fence_destroy(int fd); #endif 1f1d02de44041524f0769f60bb9cf3'>refslogtreecommitdiff
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authorNicholas Piggin <npiggin@gmail.com>2016-12-25 13:00:30 +1000
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-25 11:54:48 -0800
commit62906027091f1d02de44041524f0769f60bb9cf3 (patch)
tree6444171af03e463bb0123a392d7b91a0ae6a1f40 /include/clocksource/timer-sp804.h
parent6326fec1122cde256bd2a8c63f2606e08e44ce1d (diff)
mm: add PageWaiters indicating tasks are waiting for a page bit
Add a new page flag, PageWaiters, to indicate the page waitqueue has tasks waiting. This can be tested rather than testing waitqueue_active which requires another cacheline load. This bit is always set when the page has tasks on page_waitqueue(page), and is set and cleared under the waitqueue lock. It may be set when there are no tasks on the waitqueue, which will cause a harmless extra wakeup check that will clears the bit. The generic bit-waitqueue infrastructure is no longer used for pages. Instead, waitqueues are used directly with a custom key type. The generic code was not flexible enough to have PageWaiters manipulation under the waitqueue lock (which simplifies concurrency). This improves the performance of page lock intensive microbenchmarks by 2-3%. Putting two bits in the same word opens the opportunity to remove the memory barrier between clearing the lock bit and testing the waiters bit, after some work on the arch primitives (e.g., ensuring memory operand widths match and cover both bits). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Bob Peterson <rpeterso@redhat.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Andrew Lutomirski <luto@kernel.org> Cc: Andreas Gruenbacher <agruenba@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/clocksource/timer-sp804.h')