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 52C231E4AF for ; Thu, 18 Jun 2026 00:59:58 +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=1781744399; cv=none; b=pluEccQ03XZJ0GVyueyG4G727QXx4e5ZoLshQAJjXUZ4Dm03GNFQAtlzgfuWxhWoT6hrzR0hVftwuV1QLax8IBpAaBarDcpHqOc+G7iNzQZoQX6iZh85zPrPyXOjAUWi6R4yneAjTmA8mVe6HbszGw1ABx5V65BqvM4d+od7TW8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781744399; c=relaxed/simple; bh=qumqjKrLp67vEF9UQdLMtDnm+sBfudBzKJ4zgSKp4Z0=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=EPWSe0qIlGN3ibcmzj/SumYyn/K5tbr76cucNW+LO/K0FPIEHAPaFd28rWWtmX0pexnYkLvJhSxVo2vOLz7sFHIjM2dMSRsCJ7JtTDo6hd18srMhhDyYJB2M/zs0EWeJ9inXP6ngu3MTMCF34pzQRLv+DlKmGCkiaRmMB4u1glY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ex2EQhzv; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ex2EQhzv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A7C01F000E9; Thu, 18 Jun 2026 00:59:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781744398; bh=8cYoBpTHRFftU/yW90PN1peCw+4DvBIJK9W4EC0LA+Q=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=Ex2EQhzvLnFXngw8pgnTlStBoc8T77XNijRVG31iogC+OZtZy43rDkXEFAb0cy0oQ cWPuaRWrvqbXb3fRt2a2I0Tjge4R5aMsP+NIfE/uOc80hvuKODt0YKezYqu5MfK7gW oRUFbI/L5cm5hm+N1K8yqYmoq45SVX4+LbJV+5KPMzH1Z1NusU+TldZM0JW8wsUvO3 bgzDoCeAXkAY3e/ayOMy0dyzqGlZp498r49SBIgWN4mOvBWYPbMlMY5hALBk0+trD3 0U+oKZYjufUeZ6IVxIt8+Qmt/MdRIW3rBUaeOjj3oXkbp/eRq9kNMb+oUe+thQ+fH4 u+kvNN0o6gFHg== Date: Thu, 18 Jun 2026 09:59:53 +0900 From: Masami Hiramatsu (Google) To: Aaron Tomlin Cc: akpm@linux-foundation.org, lance.yang@linux.dev, pmladek@suse.com, linux-kernel@vger.kernel.org, neelx@suse.com, sean@ashe.io, chjohnst@gmail.com, steve@abita.co, mproche@gmail.com, nick.lange@gmail.com Subject: Re: [PATCH] hung_task: Add per-round stack trace deduplication Message-Id: <20260618095953.dd2a27cab390203f7907d4ff@kernel.org> In-Reply-To: <20260617184841.1447955-1-atomlin@atomlin.com> References: <20260617184841.1447955-1-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 Wed, 17 Jun 2026 14:48:41 -0400 Aaron Tomlin wrote: > Currently, when multiple tasks hang in the exact same location (e.g., > such as severe contention for a mutex), khungtaskd indiscriminately > reports every single instance. This wastes ring buffer space with > identical stack traces up to the defined warning limit (i.e., > kernel.hung_task_warnings), obscuring the root cause without providing > any additional diagnostic value. Good work! And I would like to see how many tasks are stacked on the same place too. Can we just skip sched_show_task() instead? Thank you, -- Masami Hiramatsu (Google)