From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C5A2A38D3F1 for ; Mon, 20 Jul 2026 06:03:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784527386; cv=none; b=baZuzf3flgf7Xw+m1uVT7BUcP42rtZl4tlUQQn1lZJ+Br2POyQ+7g4lLBEY9bKUEi0UCEsUotuUAtPuHjH6sQQow0pwroxIJkjrecsh3ZigwUPaT08zqT27nx1ZsUq3nen/tfatP0PfpiLZm73Cw1Un8/uGLiDoOQeKdNsvPbsI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784527386; c=relaxed/simple; bh=uEPH+swYiAXA6LDRAYo+Gy/APmP66Me3DtfoWEJ7vYE=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=oV1QjeydIHBj4PuOlN4YO6YLnqoA32UOjlU9baNCYrvVLa/lp9Mh6EHmt+NjU5pPKwlI9WpJFa+2R7mL0BBuH0Jmj0PoF0wR9M2WmtiaOoYdwQh8BOAGmtkFl5+o6DXRkxKzLpJDb3A6fl5aDDe5+bHDkhqHHRmsNVUpfXfwxE8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=v8mlqtfO; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="v8mlqtfO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 655571F00A3D; Mon, 20 Jul 2026 06:02:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1784527378; bh=yOxGiF6vFELEM5tyS8O0wmvx6Cz4IfDWGfxUdKoICV8=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=v8mlqtfO38KatQC2tvbpK70NY3xoP8haVBbNyItix144OWXfBeZQRrutz+gsCyYGn YZsqa/Pl790t+nuXf5QXuDsvR6yeDP13KGFbnO/++9ZwYUWp2+a5Rtc794ZVR1wBQD /4UZuVX/C/matU8F9VG8qV4ZuYD1DCQbdzPZoFWA= Date: Sun, 19 Jul 2026 23:02:57 -0700 From: Andrew Morton To: Aaron Tomlin Cc: lance.yang@linux.dev, mhiramat@kernel.org, pmladek@suse.com, linux-kernel@vger.kernel.org, david.laight.linux@gmail.com, neelx@suse.com, sean@ashe.io, chjohnst@gmail.com, steve@abita.co, mproche@gmail.com, nick.lange@gmail.com Subject: Re: [PATCH v6] hung_task: Deduplicate identical hang reports using explicit blocker tracking Message-Id: <20260719230257.6e6e87644081e94c9f9d4ac7@linux-foundation.org> In-Reply-To: <20260719161305.428947-1-atomlin@atomlin.com> References: <20260719161305.428947-1-atomlin@atomlin.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sun, 19 Jul 2026 12:13:05 -0400 Aaron Tomlin wrote: > Currently, during severe lock contention, multiple tasks can hang while > waiting on the exact same resource. The khungtaskd kthread > indiscriminately reports every single instance with a stack trace. > This can roll the kernel ring buffer and prematurely exhaust the > kernel.hung_task_warnings budget. Consequently, the kernel is left > entirely blind to subsequent, unrelated deadlocks. This does seem something we'd like to address. > To preserve the warning budget and ring buffer without sacrificing > observability, this patch introduces a two-tier deduplication mechanism: > Thanks. Hopefully Petr and Lance will be able to review this version. AI review might have found an issue: https://sashiko.dev/#/patchset/20260719161305.428947-1-atomlin@atomlin.com