From patchwork Wed Mar 16 22:45:47 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 12783241 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E922BC4332F for ; Wed, 16 Mar 2022 22:46:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232536AbiCPWrS (ORCPT ); Wed, 16 Mar 2022 18:47:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33088 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232064AbiCPWrO (ORCPT ); Wed, 16 Mar 2022 18:47:14 -0400 Received: from mail-pj1-x1029.google.com (mail-pj1-x1029.google.com [IPv6:2607:f8b0:4864:20::1029]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 590FC12AF4; Wed, 16 Mar 2022 15:45:59 -0700 (PDT) Received: by mail-pj1-x1029.google.com with SMTP id mz9-20020a17090b378900b001c657559290so3622783pjb.2; Wed, 16 Mar 2022 15:45:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=EBd+rVGks9vxgeyO63hZy1sNZZwzfinQbSZQpFKlhAw=; b=eu6OVpRj0+nZhkCSNtlFKEy3cF+RYvB6hgqFUMT1NmyDcj1kmGG+HWTbAxhmEUe18Y bqo7J3zlOhhdgDwx/apB7DPGwbmY0boUVlZuy/qxxEDXvf16Oi/8YH0oF3EftsH2VHYw Q5iwuHsMcB+FkcHBnHDv9EMzRICC9me0WpVDOX3SP0Sck/Kp1CUVYBHl8Tyl84nHcDhJ YnDDb6D3hSpyms2TuidXLgUS2Nw144mnNyvzPYWLbHH5nVmWuk+VtKGklDkku77oEqvF cU2OQL6E0kK9au10lj1Tg+P8fKw0jgHVKZ4Gb3EvKhgA4+mX2qhL1btzRfJvI5NY3zDH Zalw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; bh=EBd+rVGks9vxgeyO63hZy1sNZZwzfinQbSZQpFKlhAw=; b=b98aAM7QiucL7FKlDg0kzKbzchdrs0REOEie9omZGz9gsS03dtmeANpUWWl30PhJH4 iJeTdYmWuOFh04Ac5j23pNgIe5PfxwG6dbQ2EfoOxH+N3GDlSMh626tT3T0SUaB6dD0U yIfKRoPlwVJQQVlZ7nQSBSKOe10xPFZwSCb7XdE/W19Ij5s4LwWSKx1fG1yfhriLGOn0 O33Jr77vwH/CqFYEy2E/ig3R8H0geEOvEGkeE9breolV2vTSFVk9qxaPxYzQUys3j5gO r0Tb4W+GIGI4O3yOal1nTAXwTGg3B/OJ3kRcjGorrRClEBiUvOfWqu0PT56FiLgfJl7i SEvA== X-Gm-Message-State: AOAM532vtUG1oFxPdkQkpRRcRjv11Wwt+D2EUMHYEt13WySBclkYJevX oq7H4zi976W5GNpH35TsPEo= X-Google-Smtp-Source: ABdhPJye2AcvGypEIet/hQ5rU4qqo0zrUBf5qXPgC4FyfdCmtWmZdiqbLpjpSTAJuEd8/rnjgEM+gQ== X-Received: by 2002:a17:902:cec7:b0:151:bb1b:5c9d with SMTP id d7-20020a170902cec700b00151bb1b5c9dmr2079383plg.41.1647470758862; Wed, 16 Mar 2022 15:45:58 -0700 (PDT) Received: from balhae.hsd1.ca.comcast.net ([2601:647:4800:3540:9b43:96ac:9f9:5093]) by smtp.gmail.com with ESMTPSA id v13-20020a17090a088d00b001c64d30fa8bsm6397832pjc.1.2022.03.16.15.45.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Mar 2022 15:45:58 -0700 (PDT) Sender: Namhyung Kim From: Namhyung Kim To: Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long , Boqun Feng Cc: LKML , Thomas Gleixner , Steven Rostedt , Byungchul Park , "Paul E. McKenney" , Mathieu Desnoyers , Arnd Bergmann , Radoslaw Burny , linux-arch@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH 1/2] locking: Add lock contention tracepoints Date: Wed, 16 Mar 2022 15:45:47 -0700 Message-Id: <20220316224548.500123-2-namhyung@kernel.org> X-Mailer: git-send-email 2.35.1.894.gb6a874cedc-goog In-Reply-To: <20220316224548.500123-1-namhyung@kernel.org> References: <20220316224548.500123-1-namhyung@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org This adds two new lock contention tracepoints like below: * lock:contention_begin * lock:contention_end The lock:contention_begin takes a flags argument to classify locks. I found it useful to identify what kind of locks it's tracing like if it's spinning or sleeping, reader-writer lock, real-time, and per-cpu. Move tracepoint definitions into mutex.c so that we can use them without lockdep. Signed-off-by: Namhyung Kim --- include/trace/events/lock.h | 54 ++++++++++++++++++++++++++++++++++--- kernel/locking/lockdep.c | 1 - kernel/locking/mutex.c | 3 +++ 3 files changed, 54 insertions(+), 4 deletions(-) diff --git a/include/trace/events/lock.h b/include/trace/events/lock.h index d7512129a324..2a3df36d4fdb 100644 --- a/include/trace/events/lock.h +++ b/include/trace/events/lock.h @@ -5,11 +5,21 @@ #if !defined(_TRACE_LOCK_H) || defined(TRACE_HEADER_MULTI_READ) #define _TRACE_LOCK_H -#include +#include #include +/* flags for lock:contention_begin */ +#define LCB_F_SPIN (1U << 0) +#define LCB_F_READ (1U << 1) +#define LCB_F_WRITE (1U << 2) +#define LCB_F_RT (1U << 3) +#define LCB_F_PERCPU (1U << 4) + + #ifdef CONFIG_LOCKDEP +#include + TRACE_EVENT(lock_acquire, TP_PROTO(struct lockdep_map *lock, unsigned int subclass, @@ -78,8 +88,46 @@ DEFINE_EVENT(lock, lock_acquired, TP_ARGS(lock, ip) ); -#endif -#endif +#endif /* CONFIG_LOCK_STAT */ +#endif /* CONFIG_LOCKDEP */ + +TRACE_EVENT(contention_begin, + + TP_PROTO(void *lock, unsigned int flags), + + TP_ARGS(lock, flags), + + TP_STRUCT__entry( + __field(void *, lock_addr) + __field(unsigned int, flags) + ), + + TP_fast_assign( + __entry->lock_addr = lock; + __entry->flags = flags; + ), + + TP_printk("%p (flags=%x)", __entry->lock_addr, __entry->flags) +); + +TRACE_EVENT(contention_end, + + TP_PROTO(void *lock, int ret), + + TP_ARGS(lock, ret), + + TP_STRUCT__entry( + __field(void *, lock_addr) + __field(int, ret) + ), + + TP_fast_assign( + __entry->lock_addr = lock; + __entry->ret = ret; + ), + + TP_printk("%p (ret=%d)", __entry->lock_addr, __entry->ret) +); #endif /* _TRACE_LOCK_H */ diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 50036c10b518..08f8fb6a2d1e 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -60,7 +60,6 @@ #include "lockdep_internals.h" -#define CREATE_TRACE_POINTS #include #ifdef CONFIG_PROVE_LOCKING diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 5e3585950ec8..ee2fd7614a93 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -30,6 +30,9 @@ #include #include +#define CREATE_TRACE_POINTS +#include + #ifndef CONFIG_PREEMPT_RT #include "mutex.h" From patchwork Wed Mar 16 22:45:48 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 12783242 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0CF23C433F5 for ; Wed, 16 Mar 2022 22:46:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232720AbiCPWrU (ORCPT ); Wed, 16 Mar 2022 18:47:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33120 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229525AbiCPWrQ (ORCPT ); Wed, 16 Mar 2022 18:47:16 -0400 Received: from mail-pg1-x536.google.com (mail-pg1-x536.google.com [IPv6:2607:f8b0:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D32317AB6; Wed, 16 Mar 2022 15:46:01 -0700 (PDT) Received: by mail-pg1-x536.google.com with SMTP id c2so1251067pga.10; Wed, 16 Mar 2022 15:46:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=VwEDDEJobGkNmiRYjqXq64WHLYJ5/paFbvAI6vzbTEw=; b=WSOjnn6pcFlNHew8Yfxxulx5PI5I5+KOVNLmo2Yb7G6G9gTiyihSejJPJmlAV9Hii4 pi+1nAg+l4FbPfRGUD3ug/wVzbAWemC6jLm4g5/Pzn6aV5u9ltWwJ6dHwWHBbPejXbom ZYtYDcT/s896dlXqzI3lZ57JEqmPenKL5+3h0uIvIhDiBu/78DnEUgmk5UCvK/CcBsnX dqmgIwwVXrvXRio6FgfGAuUKH/kTlSscHRAwZyMiZC+EnsOTN6SPp8+8caJA7R1cLFA4 tL9lo8E5nMStkVugfsQdfh+hn5XsBNBNeVHBGCGNvrA5n2YnISlBXcaLt4w0mOH2p3tw hY5w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; bh=VwEDDEJobGkNmiRYjqXq64WHLYJ5/paFbvAI6vzbTEw=; b=VvnLgcN4XIMj2DZIqOyy55LFdWxRQ48hBV/h6u6RvaKMpF73xtC1p1RGZK7IFzCB9Z fyLKwDysb1GSib1ASpwfUCGSD2RlL7Ml31p8M0uXsI6w68x6/yVSpQyJhFCgXylYkU1w TyDMovh5Cpk6He/lIYmXxuz5tDh3K24atOE6oofBWbu1MW+f82kzSDa7P3QpDyTOK5ZT 1eLO6FLtUM3CXHenZNc7AgEkEJB7+k9sR/xAr+w2r4pf81+tFTFOGslHyRFZD/OfdWqP f8y65MBzGB/c7mYpq7NHchJMq1RGTdPhZ24p3D9GT5qjde7LzJnIGmhioWken6Lw4dm1 jrgg== X-Gm-Message-State: AOAM530OV3pTHYbfCtmZ2iREntv/wx6CnMQs2W0bKjLc0KAlRL59Rlsj aYsuOarZ5tzljBXCLLZsvZs= X-Google-Smtp-Source: ABdhPJzTUccwATYE4P2rM1zaFpKWXdxokL4flpnseXPVJgWAtS/nhPMSO4rJPO9gjY6KEEvbfm8gHA== X-Received: by 2002:a63:82c7:0:b0:37c:8729:a70c with SMTP id w190-20020a6382c7000000b0037c8729a70cmr1419597pgd.108.1647470760884; Wed, 16 Mar 2022 15:46:00 -0700 (PDT) Received: from balhae.hsd1.ca.comcast.net ([2601:647:4800:3540:9b43:96ac:9f9:5093]) by smtp.gmail.com with ESMTPSA id v13-20020a17090a088d00b001c64d30fa8bsm6397832pjc.1.2022.03.16.15.45.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Mar 2022 15:46:00 -0700 (PDT) Sender: Namhyung Kim From: Namhyung Kim To: Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long , Boqun Feng Cc: LKML , Thomas Gleixner , Steven Rostedt , Byungchul Park , "Paul E. McKenney" , Mathieu Desnoyers , Arnd Bergmann , Radoslaw Burny , linux-arch@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH 2/2] locking: Apply contention tracepoints in the slow path Date: Wed, 16 Mar 2022 15:45:48 -0700 Message-Id: <20220316224548.500123-3-namhyung@kernel.org> X-Mailer: git-send-email 2.35.1.894.gb6a874cedc-goog In-Reply-To: <20220316224548.500123-1-namhyung@kernel.org> References: <20220316224548.500123-1-namhyung@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Adding the lock contention tracepoints in various lock function slow paths. Note that each arch can define spinlock differently, I only added it only to the generic qspinlock for now. Signed-off-by: Namhyung Kim --- kernel/locking/mutex.c | 3 +++ kernel/locking/percpu-rwsem.c | 3 +++ kernel/locking/qrwlock.c | 9 +++++++++ kernel/locking/qspinlock.c | 5 +++++ kernel/locking/rtmutex.c | 11 +++++++++++ kernel/locking/rwbase_rt.c | 3 +++ kernel/locking/rwsem.c | 9 +++++++++ kernel/locking/semaphore.c | 14 +++++++++++++- 8 files changed, 56 insertions(+), 1 deletion(-) diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index ee2fd7614a93..c88deda77cf2 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -644,6 +644,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas } set_current_state(state); + trace_contention_begin(lock, 0); for (;;) { bool first; @@ -710,6 +711,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas skip_wait: /* got the lock - cleanup and rejoice! */ lock_acquired(&lock->dep_map, ip); + trace_contention_end(lock, 0); if (ww_ctx) ww_mutex_lock_acquired(ww, ww_ctx); @@ -721,6 +723,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas err: __set_current_state(TASK_RUNNING); __mutex_remove_waiter(lock, &waiter); + trace_contention_end(lock, ret); err_early_kill: raw_spin_unlock(&lock->wait_lock); debug_mutex_free_waiter(&waiter); diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c index c9fdae94e098..833043613af6 100644 --- a/kernel/locking/percpu-rwsem.c +++ b/kernel/locking/percpu-rwsem.c @@ -9,6 +9,7 @@ #include #include #include +#include int __percpu_init_rwsem(struct percpu_rw_semaphore *sem, const char *name, struct lock_class_key *key) @@ -154,6 +155,7 @@ static void percpu_rwsem_wait(struct percpu_rw_semaphore *sem, bool reader) } spin_unlock_irq(&sem->waiters.lock); + trace_contention_begin(sem, LCB_F_PERCPU | (reader ? LCB_F_READ : LCB_F_WRITE)); while (wait) { set_current_state(TASK_UNINTERRUPTIBLE); if (!smp_load_acquire(&wq_entry.private)) @@ -161,6 +163,7 @@ static void percpu_rwsem_wait(struct percpu_rw_semaphore *sem, bool reader) schedule(); } __set_current_state(TASK_RUNNING); + trace_contention_end(sem, 0); } bool __sched __percpu_down_read(struct percpu_rw_semaphore *sem, bool try) diff --git a/kernel/locking/qrwlock.c b/kernel/locking/qrwlock.c index ec36b73f4733..b9f6f963d77f 100644 --- a/kernel/locking/qrwlock.c +++ b/kernel/locking/qrwlock.c @@ -12,6 +12,7 @@ #include #include #include +#include /** * queued_read_lock_slowpath - acquire read lock of a queue rwlock @@ -34,6 +35,8 @@ void queued_read_lock_slowpath(struct qrwlock *lock) } atomic_sub(_QR_BIAS, &lock->cnts); + trace_contention_begin(lock, LCB_F_READ | LCB_F_SPIN); + /* * Put the reader into the wait queue */ @@ -51,6 +54,8 @@ void queued_read_lock_slowpath(struct qrwlock *lock) * Signal the next one in queue to become queue head */ arch_spin_unlock(&lock->wait_lock); + + trace_contention_end(lock, 0); } EXPORT_SYMBOL(queued_read_lock_slowpath); @@ -62,6 +67,8 @@ void queued_write_lock_slowpath(struct qrwlock *lock) { int cnts; + trace_contention_begin(lock, LCB_F_WRITE | LCB_F_SPIN); + /* Put the writer into the wait queue */ arch_spin_lock(&lock->wait_lock); @@ -79,5 +86,7 @@ void queued_write_lock_slowpath(struct qrwlock *lock) } while (!atomic_try_cmpxchg_acquire(&lock->cnts, &cnts, _QW_LOCKED)); unlock: arch_spin_unlock(&lock->wait_lock); + + trace_contention_end(lock, 0); } EXPORT_SYMBOL(queued_write_lock_slowpath); diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index cbff6ba53d56..65a9a10caa6f 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -22,6 +22,7 @@ #include #include #include +#include /* * Include queued spinlock statistics code @@ -401,6 +402,8 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) idx = node->count++; tail = encode_tail(smp_processor_id(), idx); + trace_contention_begin(lock, LCB_F_SPIN); + /* * 4 nodes are allocated based on the assumption that there will * not be nested NMIs taking spinlocks. That may not be true in @@ -554,6 +557,8 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) pv_kick_node(lock, next); release: + trace_contention_end(lock, 0); + /* * release the node */ diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 8555c4efe97c..7779ee8abc2a 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -24,6 +24,8 @@ #include #include +#include + #include "rtmutex_common.h" #ifndef WW_RT @@ -1579,6 +1581,8 @@ static int __sched __rt_mutex_slowlock(struct rt_mutex_base *lock, set_current_state(state); + trace_contention_begin(lock, LCB_F_RT); + ret = task_blocks_on_rt_mutex(lock, waiter, current, ww_ctx, chwalk); if (likely(!ret)) ret = rt_mutex_slowlock_block(lock, ww_ctx, state, NULL, waiter); @@ -1601,6 +1605,9 @@ static int __sched __rt_mutex_slowlock(struct rt_mutex_base *lock, * unconditionally. We might have to fix that up. */ fixup_rt_mutex_waiters(lock); + + trace_contention_end(lock, ret); + return ret; } @@ -1683,6 +1690,8 @@ static void __sched rtlock_slowlock_locked(struct rt_mutex_base *lock) /* Save current state and set state to TASK_RTLOCK_WAIT */ current_save_and_set_rtlock_wait_state(); + trace_contention_begin(lock, LCB_F_RT); + task_blocks_on_rt_mutex(lock, &waiter, current, NULL, RT_MUTEX_MIN_CHAINWALK); for (;;) { @@ -1712,6 +1721,8 @@ static void __sched rtlock_slowlock_locked(struct rt_mutex_base *lock) */ fixup_rt_mutex_waiters(lock); debug_rt_mutex_free_waiter(&waiter); + + trace_contention_end(lock, 0); } static __always_inline void __sched rtlock_slowlock(struct rt_mutex_base *lock) diff --git a/kernel/locking/rwbase_rt.c b/kernel/locking/rwbase_rt.c index 6fd3162e4098..ec7b1fda7982 100644 --- a/kernel/locking/rwbase_rt.c +++ b/kernel/locking/rwbase_rt.c @@ -247,11 +247,13 @@ static int __sched rwbase_write_lock(struct rwbase_rt *rwb, goto out_unlock; rwbase_set_and_save_current_state(state); + trace_contention_begin(rwb, LCB_F_WRITE | LCB_F_RT); for (;;) { /* Optimized out for rwlocks */ if (rwbase_signal_pending_state(state, current)) { rwbase_restore_current_state(); __rwbase_write_unlock(rwb, 0, flags); + trace_contention_end(rwb, -EINTR); return -EINTR; } @@ -265,6 +267,7 @@ static int __sched rwbase_write_lock(struct rwbase_rt *rwb, set_current_state(state); } rwbase_restore_current_state(); + trace_contention_end(rwb, 0); out_unlock: raw_spin_unlock_irqrestore(&rtm->wait_lock, flags); diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index acde5d6f1254..465db7bd84f8 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -27,6 +27,7 @@ #include #include #include +#include #ifndef CONFIG_PREEMPT_RT #include "lock_events.h" @@ -1014,6 +1015,8 @@ rwsem_down_read_slowpath(struct rw_semaphore *sem, long count, unsigned int stat raw_spin_unlock_irq(&sem->wait_lock); wake_up_q(&wake_q); + trace_contention_begin(sem, LCB_F_READ); + /* wait to be given the lock */ for (;;) { set_current_state(state); @@ -1035,6 +1038,7 @@ rwsem_down_read_slowpath(struct rw_semaphore *sem, long count, unsigned int stat __set_current_state(TASK_RUNNING); lockevent_inc(rwsem_rlock); + trace_contention_end(sem, 0); return sem; out_nolock: @@ -1042,6 +1046,7 @@ rwsem_down_read_slowpath(struct rw_semaphore *sem, long count, unsigned int stat raw_spin_unlock_irq(&sem->wait_lock); __set_current_state(TASK_RUNNING); lockevent_inc(rwsem_rlock_fail); + trace_contention_end(sem, -EINTR); return ERR_PTR(-EINTR); } @@ -1109,6 +1114,8 @@ rwsem_down_write_slowpath(struct rw_semaphore *sem, int state) wait: /* wait until we successfully acquire the lock */ set_current_state(state); + trace_contention_begin(sem, LCB_F_WRITE); + for (;;) { if (rwsem_try_write_lock(sem, &waiter)) { /* rwsem_try_write_lock() implies ACQUIRE on success */ @@ -1148,6 +1155,7 @@ rwsem_down_write_slowpath(struct rw_semaphore *sem, int state) __set_current_state(TASK_RUNNING); raw_spin_unlock_irq(&sem->wait_lock); lockevent_inc(rwsem_wlock); + trace_contention_end(sem, 0); return sem; out_nolock: @@ -1159,6 +1167,7 @@ rwsem_down_write_slowpath(struct rw_semaphore *sem, int state) raw_spin_unlock_irq(&sem->wait_lock); wake_up_q(&wake_q); lockevent_inc(rwsem_wlock_fail); + trace_contention_end(sem, -EINTR); return ERR_PTR(-EINTR); } diff --git a/kernel/locking/semaphore.c b/kernel/locking/semaphore.c index 9ee381e4d2a4..e3c19668dfee 100644 --- a/kernel/locking/semaphore.c +++ b/kernel/locking/semaphore.c @@ -32,6 +32,7 @@ #include #include #include +#include static noinline void __down(struct semaphore *sem); static noinline int __down_interruptible(struct semaphore *sem); @@ -209,6 +210,7 @@ static inline int __sched __down_common(struct semaphore *sem, long state, long timeout) { struct semaphore_waiter waiter; + bool tracing = false; list_add_tail(&waiter.list, &sem->wait_list); waiter.task = current; @@ -220,18 +222,28 @@ static inline int __sched __down_common(struct semaphore *sem, long state, if (unlikely(timeout <= 0)) goto timed_out; __set_current_state(state); + if (!tracing) { + trace_contention_begin(sem, 0); + tracing = true; + } raw_spin_unlock_irq(&sem->lock); timeout = schedule_timeout(timeout); raw_spin_lock_irq(&sem->lock); - if (waiter.up) + if (waiter.up) { + trace_contention_end(sem, 0); return 0; + } } timed_out: + if (tracing) + trace_contention_end(sem, -ETIME); list_del(&waiter.list); return -ETIME; interrupted: + if (tracing) + trace_contention_end(sem, -EINTR); list_del(&waiter.list); return -EINTR; }