From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="YvSNrajp" Received: from mail-lf1-x149.google.com (mail-lf1-x149.google.com [IPv6:2a00:1450:4864:20::149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A8171BD for ; Wed, 6 Dec 2023 02:09:48 -0800 (PST) Received: by mail-lf1-x149.google.com with SMTP id 2adb3069b0e04-50bf1bbf67aso3230752e87.0 for ; Wed, 06 Dec 2023 02:09:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1701857386; x=1702462186; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=U1L9PtqvjoQFgO5q+VnM788vYaeOUUwutSgupIUHrpw=; b=YvSNrajpI6D3Jtgrhf87UOkAQtV42jT6EuKVxcORvVfGmOBjxQwf/468Bfmb1Tad4w 1OG5QbY850Nsq5K/1qg3meLgwRzJoi7geNkugR5aiXqrKdt2Z3N9Zw2hD+W3/KHAr8rA ++uwupYC8+5W/+613FbIvS3CeRMPtD9J23yyyfbSTVx1EL8uKgzx+2j1mcARMWGDTxrD 33B6iu+1Vc6/z1g50EMcZk0hVY9K/ZvfYhj9+3vwOgG3jiI8veHsyfCdC2qwa/oDFrdk z2vZbDaybdLwA5BiXODRoKLYm8OBWq3mUfoy6BYogLIqhPt2qBxLK044cU2kyvWqDHxG pjJA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701857386; x=1702462186; h=cc: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=U1L9PtqvjoQFgO5q+VnM788vYaeOUUwutSgupIUHrpw=; b=EFYaCmT9URfCpwziQoRjE0NoO5SpupOoj8LmDsa5WGrLQUt5ZxLIvZ2y605HVT8j4k EPsAp60kONZ6/Yi6F5pO+4cqGgHaLMGmSs1IYj4viuKKxytNQUFXYOQL8dTvIIGjc5a2 wvTxaPBePQQrIlAgVRPWI4M2VPZv3MKwUjUmwejXL+S41yyd4KhCdDVKvPW/Z0IpNZnP jhDORG9Wzy1guAVFqnKHd27plLdguKGKwJ7D8u+JaO8+D9aoNS0at/Im4suNupQgfNtl IYHstvfQHDRtw2gl6qYg6X5q3Kgn2yGyhHebjQB05OB0L2MQIGZUx7Ru2vDAPWxB7X/O J3ZA== X-Gm-Message-State: AOJu0YwUTGtLaQGF/mLnAWHZoJD3bj6RoN5ndR8YlQ4Zd1qKWlCyPaw3 efo5+3G/9u2hMkc/F0e9Fex1qzkC3DhE2kw= X-Google-Smtp-Source: AGHT+IGcZaa0HIqhd1WvwmU9/aezaZATfqG4dYdD1uU8/+cxuckpLe6BI/oIuVMP4tyS6jJfsHxO67Crxq6ZihE= X-Received: from aliceryhl2.c.googlers.com ([fda3:e722:ac3:cc00:68:949d:c0a8:572]) (user=aliceryhl job=sendgmr) by 2002:ac2:5f6f:0:b0:50b:f822:eacf with SMTP id c15-20020ac25f6f000000b0050bf822eacfmr7060lfc.9.1701857386498; Wed, 06 Dec 2023 02:09:46 -0800 (PST) Date: Wed, 06 Dec 2023 10:09:23 +0000 In-Reply-To: <20231206-rb-new-condvar-methods-v1-0-33a4cab7fdaa@google.com> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20231206-rb-new-condvar-methods-v1-0-33a4cab7fdaa@google.com> X-Developer-Key: i=aliceryhl@google.com; a=openpgp; fpr=49F6C1FAA74960F43A5B86A1EE7A392FDE96209F X-Developer-Signature: v=1; a=openpgp-sha256; l=1342; i=aliceryhl@google.com; h=from:subject:message-id; bh=gjsFTUAv4pM5ZDJTd0sbTeFQ61hWz6BaOzuWVUqxq5w=; b=owEBbQKS/ZANAwAKAQRYvu5YxjlGAcsmYgBlcEhjgsTlj7q910nqwwTDSnkQsaj8PWPzf/p24 xNoUDnQ9huJAjMEAAEKAB0WIQSDkqKUTWQHCvFIvbIEWL7uWMY5RgUCZXBIYwAKCRAEWL7uWMY5 Rhx4D/9VIZRDqteITL/cUGikpx6VfrHfTxuyPcTCIR+GBin1ORtXgW+Bt6OwxBi3hwmsdrhgAbD 3108bBJ5qfRCoI6Lt5pmvQwWE6X1rBF1CWvwWhJHseTDg5ddzP9IiMRforJXCt7kitqp1ORX2TK i+1/aJomLqn7Wgka2NGua5btH6ixeZetd7KZMe+0QeeYMM7326rbf16LSoOSOcHcZSzL5vAxD19 F/H+hEfilOKYsoVGpFPbDYpXcO7zIuWfKVssGmFXhpROxJM4iFdDytnmXsv3d/Ak76N+hJBzcn9 ZJi5twiTHlgWjEclmhEVG7vJA9mmnGfKPWv0ddRn1+d+gXksYgqDInQ/vS3XrkuC7VP5aegFabQ tPjSCyS4iJh75zIgbdPgDISDIwict5SjjC0MNli6WI5pNOugCjP5fekPne54LC7aSsAUGLsa6PI vWFX1AsnQViiHdsFFnPVbTRYc0V8o07TbPdlx4tMsdJduWvF8+wW5IGZ1IffvFess7dcrksF6np AikW4+oesXvSf/CMoXl+kJy9EcxcXRP91Oec08ayBv4KSdRit3ScvYmjsE6PdxARtylFOhIR87I 7OM/5aalMAmvl3lHw52Kn7b7nxBalpM73+jnBjzKnqz/FO2j2Cm4jTNm685HgT6o/+FkGG5PPRB /L7P5iNaWdSc9+g== X-Mailer: b4 0.13-dev-26615 Message-ID: <20231206-rb-new-condvar-methods-v1-1-33a4cab7fdaa@google.com> Subject: [PATCH 1/2] rust: sync: add `CondVar::notify_sync` From: Alice Ryhl To: Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , Gary Guo , "=?utf-8?q?Bj=C3=B6rn_Roy_Baron?=" , Benno Lossin , Andreas Hindborg , Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Alice Ryhl Content-Type: text/plain; charset="utf-8" Wake up another thread synchronously. This method behaves like `notify_one`, except that it hints to the scheduler that the current thread is about to go to sleep, so it should schedule the target thread on the same CPU. This is used by Rust Binder as a performance optimization. When sending a transaction to a different process, we usually know which thread will handle it, so we can schedule that thread for execution next on this CPU for better cache locality. Signed-off-by: Alice Ryhl --- rust/kernel/sync/condvar.rs | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/rust/kernel/sync/condvar.rs b/rust/kernel/sync/condvar.rs index b679b6f6dbeb..9861c6749ad0 100644 --- a/rust/kernel/sync/condvar.rs +++ b/rust/kernel/sync/condvar.rs @@ -155,6 +155,12 @@ fn notify(&self, count: i32, flags: u32) { }; } + /// Calls the kernel function to notify one thread synchronously. + pub fn notify_sync(&self) { + // SAFETY: `wait_list` points to valid memory. + unsafe { bindings::__wake_up_sync(self.wait_list.get(), bindings::TASK_NORMAL) }; + } + /// Wakes a single waiter up, if any. /// /// This is not 'sticky' in the sense that if no thread is waiting, the notification is lost -- 2.43.0.rc2.451.g8631bc7472-goog