user/sven/linux.git/kernel/jump_label.c, branch v3.10.67

jump_label: Export jump_label_rate_limit()

2012-08-06T16:00:35Z

CC: Jason Baron CC: Ingo Molnar CC: Peter Zijlstra Signed-off-by: Gleb Natapov Acked-by: Jason Baron Signed-off-by: Avi Kivity

static keys: Inline the static_key_enabled() function

2012-02-28T19:01:08Z

In the jump label enabled case, calling static_key_enabled() results in a function call. The function returns the results of a compare, so it really doesn't need the overhead of a full function call. Let's make it 'static inline' for both the jump label enabled and disabled cases. Signed-off-by: Jason Baron Cc: a.p.zijlstra@chello.nl Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@polymtl.ca Cc: Andrew Morton Cc: Linus Torvalds Link: http://lkml.kernel.org/r/201202281849.q1SIn1p2023270@int-mx10.intmail.prod.int.phx2.redhat.com Signed-off-by: Ingo Molnar

static keys: Introduce 'struct static_key', static_key_true()/false() and static_key_slow_[inc|dec]()

2012-02-24T09:05:59Z

So here's a boot tested patch on top of Jason's series that does all the cleanups I talked about and turns jump labels into a more intuitive to use facility. It should also address the various misconceptions and confusions that surround jump labels. Typical usage scenarios: #include struct static_key key = STATIC_KEY_INIT_TRUE; if (static_key_false(&key)) do unlikely code else do likely code Or: if (static_key_true(&key)) do likely code else do unlikely code The static key is modified via: static_key_slow_inc(&key); ... static_key_slow_dec(&key); The 'slow' prefix makes it abundantly clear that this is an expensive operation. I've updated all in-kernel code to use this everywhere. Note that I (intentionally) have not pushed through the rename blindly through to the lowest levels: the actual jump-label patching arch facility should be named like that, so we want to decouple jump labels from the static-key facility a bit. On non-jump-label enabled architectures static keys default to likely()/unlikely() branches. Signed-off-by: Ingo Molnar Acked-by: Jason Baron Acked-by: Steven Rostedt Cc: a.p.zijlstra@chello.nl Cc: mathieu.desnoyers@efficios.com Cc: davem@davemloft.net Cc: ddaney.cavm@gmail.com Cc: Linus Torvalds Link: http://lkml.kernel.org/r/20120222085809.GA26397@elte.hu Signed-off-by: Ingo Molnar

jump label: Fix compiler warning

2012-02-22T06:59:40Z

While cross-compiling on sparc64, I found: kernel/jump_label.c: In function 'jump_label_update': kernel/jump_label.c:447:40: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] Fix by casting to 'unsigned long'. Signed-off-by: Jason Baron Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: davem@davemloft.net Cc: ddaney.cavm@gmail.com Cc: a.p.zijlstra@chello.nl Link: http://lkml.kernel.org/r/08026cbc6df80619cae833ef1ebbbc43efab69ab.1329851692.git.jbaron@redhat.com Signed-off-by: Ingo Molnar

jump label: Add a WARN() if jump label key count goes negative

2012-02-22T06:59:39Z

The count on a jump label key should never go negative. Add a WARN() to check for this condition. Signed-off-by: Jason Baron Cc: Gleb Natapov Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: davem@davemloft.net Cc: ddaney.cavm@gmail.com Cc: a.p.zijlstra@chello.nl Link: http://lkml.kernel.org/r/3c68556121be4d1920417a3fe367da1ec38246b4.1329851692.git.jbaron@redhat.com Signed-off-by: Ingo Molnar

Merge remote-tracking branch 'tip/perf/core' into kvm-updates/3.3

2011-12-27T09:22:24Z

* tip/perf/core: (66 commits) perf, x86: Expose perf capability to other modules perf, x86: Implement arch event mask as quirk x86, perf: Disable non available architectural events jump_label: Provide jump_label_key initializers jump_label, x86: Fix section mismatch perf, core: Rate limit perf_sched_events jump_label patching perf: Fix enable_on_exec for sibling events perf: Remove superfluous arguments perf, x86: Prefer fixed-purpose counters when scheduling perf, x86: Fix event scheduler for constraints with overlapping counters perf, x86: Implement event scheduler helper functions perf: Avoid a useless pmu_disable() in the perf-tick x86/tools: Add decoded instruction dump mode x86: Update instruction decoder to support new AVX formats x86/tools: Fix insn_sanity message outputs x86/tools: Fix instruction decoder message output x86: Fix instruction decoder to handle grouped AVX instructions x86/tools: Fix Makefile to build all test tools perf test: Soft errors shouldn't stop the "Validate PERF_RECORD_" test perf test: Validate PERF_RECORD_ events and perf_sample fields ... Signed-off-by: Avi Kivity * commit 'b3d9468a8bd218a695e3a0ff112cd4efd27b670a': (66 commits) perf, x86: Expose perf capability to other modules perf, x86: Implement arch event mask as quirk x86, perf: Disable non available architectural events jump_label: Provide jump_label_key initializers jump_label, x86: Fix section mismatch perf, core: Rate limit perf_sched_events jump_label patching perf: Fix enable_on_exec for sibling events perf: Remove superfluous arguments perf, x86: Prefer fixed-purpose counters when scheduling perf, x86: Fix event scheduler for constraints with overlapping counters perf, x86: Implement event scheduler helper functions perf: Avoid a useless pmu_disable() in the perf-tick x86/tools: Add decoded instruction dump mode x86: Update instruction decoder to support new AVX formats x86/tools: Fix insn_sanity message outputs x86/tools: Fix instruction decoder message output x86: Fix instruction decoder to handle grouped AVX instructions x86/tools: Fix Makefile to build all test tools perf test: Soft errors shouldn't stop the "Validate PERF_RECORD_" test perf test: Validate PERF_RECORD_ events and perf_sample fields ...

jump-label: export jump_label_inc/jump_label_dec

2011-12-27T09:22:04Z

Export these two symbols, they will be used by KVM mmu audit Signed-off-by: Xiao Guangrong Signed-off-by: Avi Kivity

jump_label: Provide jump_label_key initializers

2011-12-06T19:41:03Z

Provide two initializers for jump_label_key that initialize it enabled or disabled. Also modify all jump_label code to allow for jump_labels to be initialized enabled. Signed-off-by: Peter Zijlstra Cc: Jason Baron Link: http://lkml.kernel.org/n/tip-p40e3yj21b68y03z1yv825e7@git.kernel.org Signed-off-by: Ingo Molnar

jump_label, x86: Fix section mismatch

2011-12-06T19:41:02Z

WARNING: arch/x86/kernel/built-in.o(.text+0x4c71): Section mismatch in reference from the function arch_jump_label_transform_static() to the function .init.text:text_poke_early() The function arch_jump_label_transform_static() references the function __init text_poke_early(). This is often because arch_jump_label_transform_static lacks a __init annotation or the annotation of text_poke_early is wrong. Signed-off-by: Peter Zijlstra Cc: Jason Baron Link: http://lkml.kernel.org/n/tip-9lefe89mrvurrwpqw5h8xm8z@git.kernel.org Signed-off-by: Ingo Molnar

perf, core: Rate limit perf_sched_events jump_label patching

2011-12-06T07:34:02Z

jump_lable patching is very expensive operation that involves pausing all cpus. The patching of perf_sched_events jump_label is easily controllable from userspace by unprivileged user. When te user runs a loop like this: "while true; do perf stat -e cycles true; done" ... the performance of my test application that just increments a counter for one second drops by 4%. This is on a 16 cpu box with my test application using only one of them. An impact on a real server doing real work will be worse. Performance of KVM PMU drops nearly 50% due to jump_lable for "perf record" since KVM PMU implementation creates and destroys perf event frequently. This patch introduces a way to rate limit jump_label patching and uses it to fix the above problem. I believe that as jump_label use will spread the problem will become more common and thus solving it in a generic code is appropriate. Also fixing it in the perf code would result in moving jump_label accounting logic to perf code with all the ifdefs in case of JUMP_LABEL=n kernel. With this patch all details are nicely hidden inside jump_label code. Signed-off-by: Gleb Natapov Acked-by: Jason Baron Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20111127155909.GO2557@redhat.com Signed-off-by: Ingo Molnar