From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D4F87202998 for ; Tue, 29 Jul 2025 02:26:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753756010; cv=none; b=u2WHm0jrAraeNG7JWhBMiiM66NXeCO6OTUcN/yvM8fvWAKe6uWUIcmVIr8RI0qpSBmOu3/2V//hpamlUVE0Rk6q7u1ROOIhsHEEC9EeTSk/cP0UUPCSRmWnAyPRU6VQZXkElipaM0rGbFhRpe/zv8VKyNeR4ZMaQBktF0OX0G/Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753756010; c=relaxed/simple; bh=4ISGW0qCLPw0BM53+WZj1UO7Eu/DiHDQi040hwtDTro=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Content-Type; b=d2o2a1QtuktGsGSCwbquI5OcpDtmh92Ho6hKVXVq6ASYYkc9GyQoz3iGyQtPsUNwEY++hRFLsLy8nLmK+qShc1T5PuVkKKRcyEJBT2chk6piShKspJtS0VfVz2SMi4FY7/DSuaxrwbNok6+b9bRZXaHcFFsQpukzKdy2NenJnDM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--yuzhuo.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=yvy3uJGj; arc=none smtp.client-ip=209.85.214.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--yuzhuo.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="yvy3uJGj" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-23ffd934201so19792385ad.3 for ; Mon, 28 Jul 2025 19:26:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1753756008; x=1754360808; darn=vger.kernel.org; h=to:from:subject:message-id:references:mime-version:in-reply-to:date :from:to:cc:subject:date:message-id:reply-to; bh=MZDFdixHdB12wePHGCdlmdShiJsvmZbe+2EaeGSxRAI=; b=yvy3uJGjVeSFxfka0z1c0zQiLzmtMvwka3ld+dW61JGQdNKt+rPtw2RRh0s5zkj7vB TBiB2Wkdp7NlJv0AwYrY8jby+27RbFo6+QsLLaBQu2BL4Sr3axPH6F8WuG2vyEZr2Ze6 leFFoYnXCNCcMUe4j1dSPmZYx+qtDvYMn0UQepywD+Dt0zI2BJROOGC1dUUGuT36GnKN 9xyTVl0q3pTGTjg+W8ODZbLVUJVYPDBYqipjkCJisMLnl66wlT9L7GLcjXgS5uVavXQV JggyLiBGICQHWGtSPSmyAA3wKYcCc0ri9yaSW3McrCdgmZK8JFd6PDFGkEMky/MkxKSY oB5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1753756008; x=1754360808; h=to:from:subject:message-id:references:mime-version:in-reply-to:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=MZDFdixHdB12wePHGCdlmdShiJsvmZbe+2EaeGSxRAI=; b=VrcXSHKEpslVhloDyuD4XnNDLx9yY911Klm1v0orcMxUC1GjEzQbMcu5GT072f/Ro3 FGNPar2vJa10AU6KsnYm8bQ9qm2XHFfIIMQ5rkbd+c17RbdCvl/ady6tIZJF3A082ykb 4Iya0Gfa4zg9hkk0h3yGqsCiw/nEV26CY+7tbmAWOv1FJ0ZB+ylaKlUP7Jjv9CZ9XjuW I8BBQYVUVx/LA7Hfj8VoCfcinHusZBbxZFUswg+Sxb8pP0kRB05oIgAnf2AkQvsuliEO 8TI9UD32kPAyXSllefhfO+AzdoIbbLxoYNIDdS/oO6yPSJ5EXQnPkL0Sz3yBqw4mxyaY qCHQ== X-Forwarded-Encrypted: i=1; AJvYcCU3IBGZkA8sWYBSqDloTRLVtPJtbR/9uStTCFawhYygPWjMen8IiKroLF3MbvvxaJbaqrN9XsEHaAYW8ZoZKAvX@vger.kernel.org X-Gm-Message-State: AOJu0Yw2TfGDm2tuL8Q/0qeXq2EnMS7B1eleblWCj9W44MX2MXgKEig4 AryvrlPXk5Q3hmmMMkOugu3l3gWNQ+gKmLf8dfr1K+mEBj2F0zlJNkuQn4MHoS81YHTfbGJWAh4 uNeyscg== X-Google-Smtp-Source: AGHT+IGT/z+KJFAljNSW6NANlfZq/RIKeylnOweKpxXQz/9KYWN22xeESvB+lMHSNFQTjy3lnaZ3WI8wSiY= X-Received: from plbme16.prod.google.com ([2002:a17:902:fc50:b0:23f:8c3f:e0fc]) (user=yuzhuo job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:f54c:b0:240:71a5:f30 with SMTP id d9443c01a7336-24071a51d35mr8329275ad.22.1753756008099; Mon, 28 Jul 2025 19:26:48 -0700 (PDT) Date: Mon, 28 Jul 2025 19:26:35 -0700 In-Reply-To: <20250729022640.3134066-1-yuzhuo@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250729022640.3134066-1-yuzhuo@google.com> X-Mailer: git-send-email 2.50.1.487.gc89ff58d15-goog Message-ID: <20250729022640.3134066-3-yuzhuo@google.com> Subject: [PATCH v1 2/7] tools: Import smp_cond_load and atomic_cond_read From: Yuzhuo Jing To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Liang Kan , Yuzhuo Jing , Yuzhuo Jing , Andrea Parri , Palmer Dabbelt , Charlie Jenkins , Sebastian Andrzej Siewior , Kumar Kartikeya Dwivedi , Alexei Starovoitov , Barret Rhoden , Alexandre Ghiti , Guo Ren , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Import generic barrier implementation of smp_cond_load_{acquire,relaxed} and import macro definitions of atomic_cond_read_{acquire,relaxed}. Signed-off-by: Yuzhuo Jing --- tools/include/asm/barrier.h | 58 ++++++++++++++++++++++++++++++++++++ tools/include/linux/atomic.h | 3 ++ 2 files changed, 61 insertions(+) diff --git a/tools/include/asm/barrier.h b/tools/include/asm/barrier.h index 0c21678ac5e6..5150c955c1c9 100644 --- a/tools/include/asm/barrier.h +++ b/tools/include/asm/barrier.h @@ -63,3 +63,61 @@ do { \ ___p1; \ }) #endif + +#ifndef cpu_relax +#define cpu_relax() ({}) +#endif + +/** + * smp_acquire__after_ctrl_dep() - Provide ACQUIRE ordering after a control dependency + * + * A control dependency provides a LOAD->STORE order, the additional RMB + * provides LOAD->LOAD order, together they provide LOAD->{LOAD,STORE} order, + * aka. (load)-ACQUIRE. + * + * Architectures that do not do load speculation can have this be barrier(). + */ +#ifndef smp_acquire__after_ctrl_dep +#define smp_acquire__after_ctrl_dep() smp_rmb() +#endif + +/** + * smp_cond_load_relaxed() - (Spin) wait for cond with no ordering guarantees + * @ptr: pointer to the variable to wait on + * @cond: boolean expression to wait for + * + * Equivalent to using READ_ONCE() on the condition variable. + * + * Due to C lacking lambda expressions we load the value of *ptr into a + * pre-named variable @VAL to be used in @cond. + */ +#ifndef smp_cond_load_relaxed +#define smp_cond_load_relaxed(ptr, cond_expr) ({ \ + typeof(ptr) __PTR = (ptr); \ + __unqual_scalar_typeof(*ptr) VAL; \ + for (;;) { \ + VAL = READ_ONCE(*__PTR); \ + if (cond_expr) \ + break; \ + cpu_relax(); \ + } \ + (typeof(*ptr))VAL; \ +}) +#endif + +/** + * smp_cond_load_acquire() - (Spin) wait for cond with ACQUIRE ordering + * @ptr: pointer to the variable to wait on + * @cond: boolean expression to wait for + * + * Equivalent to using smp_load_acquire() on the condition variable but employs + * the control dependency of the wait to reduce the barrier on many platforms. + */ +#ifndef smp_cond_load_acquire +#define smp_cond_load_acquire(ptr, cond_expr) ({ \ + __unqual_scalar_typeof(*ptr) _val; \ + _val = smp_cond_load_relaxed(ptr, cond_expr); \ + smp_acquire__after_ctrl_dep(); \ + (typeof(*ptr))_val; \ +}) +#endif diff --git a/tools/include/linux/atomic.h b/tools/include/linux/atomic.h index 332a34177995..6baee2c41b55 100644 --- a/tools/include/linux/atomic.h +++ b/tools/include/linux/atomic.h @@ -36,4 +36,7 @@ void atomic_long_set(atomic_long_t *v, long i); #define cmpxchg_release cmpxchg #endif +#define atomic_cond_read_acquire(v, c) smp_cond_load_acquire(&(v)->counter, (c)) +#define atomic_cond_read_relaxed(v, c) smp_cond_load_relaxed(&(v)->counter, (c)) + #endif /* __TOOLS_LINUX_ATOMIC_H */ -- 2.50.1.487.gc89ff58d15-goog