From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f179.google.com (mail-pl1-f179.google.com [209.85.214.179]) (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 D09E228726A for ; Mon, 10 Nov 2025 16:37:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762792652; cv=none; b=GGj02VwqZ8cL5RPx9ZmJxCA/JH6tssrZty+d0KKhgWN23+rIjmxYCfVy2+cxZhzDueA2Vsaj4z5jzaqXJwAYRPZHQz0OGJw6zkDo31XOgzANCmcjIowt6S9o2Ki0oy+xklm8yVguL8YU/QZQWxdqaI8FSOBrbdoMpu6GqUIaENU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762792652; c=relaxed/simple; bh=HNu7Dcd5vvNfh2oB/9//HT00PJ8dhROTfKt08npi0Xo=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Xb2tpc13KPztmOfK747RTtdStbXOEePslwmAraCSiyBBMa6X7JHm5JfIxJaYqyQPFmLevbQGRmMVmzmjMbCReSDGQ1k3nliDewezEWsOuDhBr/Z1fmQwFn9BQrlfao+Z4A6ZYmf+rU6B/NfdKrKApQktcoWKkcYtEOBNX+fEAPs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=BkxQVfEk; arc=none smtp.client-ip=209.85.214.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BkxQVfEk" Received: by mail-pl1-f179.google.com with SMTP id d9443c01a7336-297f8c26dc7so15259085ad.2 for ; Mon, 10 Nov 2025 08:37:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1762792646; x=1763397446; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:from:to:cc:subject:date:message-id :reply-to; bh=NvOciuVeFDrZI28wwbDFkVg+RFkidCZi4q1TH1/mApw=; b=BkxQVfEkEBOYEpCeUBV842In3TXrZSeDm6WTzj4dnhlJnM/V9G58u2nYPa/Knffz1U 6Sy/ftr0I4ErZmavti+TsQOhwPBv2DFSW37bpJoP53In1JSYftTGImWiVtiBsQ2ORN47 MCtLtxT1bidHRtJveRiETAElwfMJt+wiOLmV8za6EJ4sxmeGzyPTx42LXlH/oVmWpdpu 8Q8ZKqD2Cf5esbgYH3GHQRNwJviYlHsamyt0H/EcrG1ewtc0sTUyHpgeo53KexFSmBxC D2AnvxOe9DAEcB0yGOEe4o7YPl0fkn5C0HAJC9CRr+lr/zjPEjRd7v23NsEMoKX3nHrH wP0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762792646; x=1763397446; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:x-gm-gg:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=NvOciuVeFDrZI28wwbDFkVg+RFkidCZi4q1TH1/mApw=; b=Cx+ZrRTTHlHXPb5ROUdo8knMstwU844v+qWixbTnxOq9HqcPBkKZFZ4oXuRq1WtvJ/ GP6o6khqvRKV1ExBLW4Ry86GpxJ9m08by3suwmnuYmy2wb4nGWVJARuW/erFKKmKPa1D FyQHrBhZKKqesrh8SswFRSxAZ0W+7ulhmcMck7PVX+Txkc+GSj/DeSxMB+lMgdFsC1OJ GoZi1FT7a7MEqWn2sKJmKc28bMmvxqGsNmDK377CAommQOWmcNTs1qdEDpvX2wW/oTRb cWC+72XOuOjJpBi2fwAz49q7aHkA+GZIBGbK48VASNB1uQ0OMusTw2UxiGi+zNcjFMPw 1mjQ== X-Forwarded-Encrypted: i=1; AJvYcCW7wEhjwY1TZav6sH9wht+410WAl1yVk+Qq0CqwgUxiSKTMuC5wYWE9zSQ/D909Ek+WsFsxA2t44XIGx+rnXlUb@vger.kernel.org X-Gm-Message-State: AOJu0YzYZ876pJ7RKVIIGhRwNd/oMhHKnLxP/Ov4zjVUiFR3rwuYJEel DUTXZRQ2RUV1FqtPGhcWweSZUZlnPl4vL4PwqXw+jJk4F83cUufBZq5g X-Gm-Gg: ASbGncvYBtbS8o4dFgohJYkLTbiq7CiGev7qBYTjsK3HYXc4MJJ4u6+aaIptviUP7Sy sXPn9DRE0VfuRKAWyx0oaPbEWuJAyZsp63X+rFdf2cBDnwq2pBI7waGCVOPjs+KSBVqCq57NFii ddoh8nvSGrEmuejVtcxYxrxqqt7w2dvfhdUVXICuc93jGBU9Oamgn0ZBoqNNRGDEeuK2YKkotPv M4jTYZl2/cYpJdkid43h17ypS0+PUbUYRok6I0oPezZ7H/cwT9mSAB44CGyZN3GOP4GT+43ypq/ AjfDy3PjpZSLzNg7NZVW2QyDWSEXHDKk/AWtCOf+L72wJmno1+PrBt8vLtQqNVtvviA7/gkamoC XU8MMGmnfMW6Dhl6Xd/R7n0YaIetsM2HiKU4Usv3Gd8+eFQLkDQ/fMq4PfqXBngl73qY6RuUunr pvcIFejdsq4b8= X-Google-Smtp-Source: AGHT+IHgMULgC+DBrIvta4Gt30Ay5gyo7asjfOY4+q2Dbpcc5OVehm1NQ3FiY7ELdv1UD5aLJGKDyg== X-Received: by 2002:a17:902:da4b:b0:27e:f018:d2fb with SMTP id d9443c01a7336-297e540dbf8mr108586355ad.6.1762792645676; Mon, 10 Nov 2025 08:37:25 -0800 (PST) Received: from localhost ([103.88.46.62]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-29650c5ce87sm150078775ad.29.2025.11.10.08.37.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Nov 2025 08:37:25 -0800 (PST) From: Jinchao Wang To: Andrew Morton , "Masami Hiramatsu (Google)" , Peter Zijlstra , Randy Dunlap , Marco Elver , Mike Rapoport , Alexander Potapenko , Adrian Hunter , Alexander Shishkin , Alice Ryhl , Andrey Konovalov , Andrey Ryabinin , Andrii Nakryiko , Ard Biesheuvel , Arnaldo Carvalho de Melo , Ben Segall , Bill Wendling , Borislav Petkov , Catalin Marinas , Dave Hansen , David Hildenbrand , David Kaplan , "David S. Miller" , Dietmar Eggemann , Dmitry Vyukov , "H. Peter Anvin" , Ian Rogers , Ingo Molnar , James Clark , Jinchao Wang , Jinjie Ruan , Jiri Olsa , Jonathan Corbet , Juri Lelli , Justin Stitt , kasan-dev@googlegroups.com, Kees Cook , "Liam R. Howlett" , "Liang Kan" , Linus Walleij , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-perf-users@vger.kernel.org, linux-trace-kernel@vger.kernel.org, llvm@lists.linux.dev, Lorenzo Stoakes , Mark Rutland , Masahiro Yamada , Mathieu Desnoyers , Mel Gorman , Michal Hocko , Miguel Ojeda , Nam Cao , Namhyung Kim , Nathan Chancellor , Naveen N Rao , Nick Desaulniers , Rong Xu , Sami Tolvanen , Steven Rostedt , Suren Baghdasaryan , Thomas Gleixner , =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= , Valentin Schneider , Vincent Guittot , Vincenzo Frascino , Vlastimil Babka , Will Deacon , workflows@vger.kernel.org, x86@kernel.org Subject: [PATCH v8 10/27] mm/ksw: support CPU hotplug Date: Tue, 11 Nov 2025 00:36:05 +0800 Message-ID: <20251110163634.3686676-11-wangjinchao600@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251110163634.3686676-1-wangjinchao600@gmail.com> References: <20251110163634.3686676-1-wangjinchao600@gmail.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Register CPU online/offline callbacks via cpuhp_setup_state_nocalls() so stack watches are installed/removed dynamically as CPUs come online or go offline. When a new CPU comes online, register a hardware breakpoint for the holder, avoiding races with watch_on()/watch_off() that may run on another CPU. The watch address will be updated the next time watch_on() is called. Signed-off-by: Jinchao Wang --- mm/kstackwatch/watch.c | 52 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) diff --git a/mm/kstackwatch/watch.c b/mm/kstackwatch/watch.c index f922b4164be5..99184f63d7e3 100644 --- a/mm/kstackwatch/watch.c +++ b/mm/kstackwatch/watch.c @@ -85,6 +85,48 @@ static void ksw_watch_on_local_cpu(void *info) WARN(ret, "fail to reinstall HWBP on CPU%d ret %d", cpu, ret); } +static int ksw_watch_cpu_online(unsigned int cpu) +{ + struct perf_event_attr attr; + struct ksw_watchpoint *wp; + call_single_data_t *csd; + struct perf_event *bp; + + mutex_lock(&all_wp_mutex); + list_for_each_entry(wp, &all_wp_list, list) { + attr = wp->attr; + attr.bp_addr = (u64)&holder; + bp = perf_event_create_kernel_counter(&attr, cpu, NULL, + ksw_watch_handler, wp); + if (IS_ERR(bp)) { + pr_warn("%s failed to create watch on CPU %d: %ld\n", + __func__, cpu, PTR_ERR(bp)); + continue; + } + + per_cpu(*wp->event, cpu) = bp; + csd = per_cpu_ptr(wp->csd, cpu); + INIT_CSD(csd, ksw_watch_on_local_cpu, wp); + } + mutex_unlock(&all_wp_mutex); + return 0; +} + +static int ksw_watch_cpu_offline(unsigned int cpu) +{ + struct ksw_watchpoint *wp; + struct perf_event *bp; + + mutex_lock(&all_wp_mutex); + list_for_each_entry(wp, &all_wp_list, list) { + bp = per_cpu(*wp->event, cpu); + if (bp) + unregister_hw_breakpoint(bp); + } + mutex_unlock(&all_wp_mutex); + return 0; +} + static void ksw_watch_update(struct ksw_watchpoint *wp, ulong addr, u16 len) { call_single_data_t *csd; @@ -206,6 +248,16 @@ int ksw_watch_init(void) if (ret <= 0) return -EBUSY; + ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, + "kstackwatch:online", + ksw_watch_cpu_online, + ksw_watch_cpu_offline); + if (ret < 0) { + ksw_watch_free(); + pr_err("Failed to register CPU hotplug notifier\n"); + return ret; + } + return 0; } -- 2.43.0