From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792624508; b=NujoK/MSVzmFkpy+qbHnfr4I9leR2/3mlEkFiNXutUCnSdNduOob1yiCyBWte79PWtWr 37q+xBaJUPNJKwS/oPOrvlMfZ83lbi2c1caZ8ylYy7EW4fQoNbiF0s8hm+6mWF8TGgNTM uANAMV/APt7B8dsz118qT9DM0NNLte6TsmFnw0dr6+gYMi2aS8Z59Wc8CnPF+xUKwKmrR hd7wY2k5vZqCpsxMFi4gjxKH25BZMsupKil+9b+nrK4b9wdVKBf3GKvaI9Ba6nQLWv5mB YHBg6N/fSEwKjobZUThLcHzgbeqb7+PWkjrhDr0TiE++z2k9z1FBy1x5fLRcvazY/sw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792624508; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-Id: In-Reply-To:References:X-Mailer:Mime-Version:Content-Type: Content-Transfer-Encoding; bh=/7KJVKeGeRGSyQHPy7x4oaw0DqaNO6jqSgeT0PXKjfk=; b=4S2buqNgYYonHBVJGr9LTEIgmbYldSF+hjkXg6k1awzGWDk+hON4fo/BhLOsDzTkkFAO enW0s2rGww43Vpv0tspMv3FpyW3n5+vYrp8KrC/rQ1LrMao4Ppl4wjD59gnKPl6rwtqWh 521EyjX7BWkr0eycc6vTLWJstrZZfvSz3nifF0+03iJLI+/dRQOcxqVlzU81jYUo0KrsV FU0YjpieFsrn1JaXbqV2ACfe/0J/OyOdB0RLL+1yp0zUweHb8w/GeAvVRwkYCG8cHcLG3 C5xWlr2LBDOu2tCdHzdil7DtxnYIxSO2BVrVEfPG8ePhg4kie0QLJBDvbRfMiGB+exg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=M92pQkTT; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A72CA606A319; Wed, 21 Oct 2026 23:15:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=M92pQkTT Received: by smtp.kernel.org (Postfix) with ESMTPSA id E4A8B1F000C1; Wed, 21 Oct 2026 23:15:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1792624507; bh=/7KJVKeGeRGSyQHPy7x4oaw0DqaNO6jqSgeT0PXKjfk=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=M92pQkTTf1ekioYEsd8uN2bo0UfKQ+GoiB6y+rYNS37ljVTFgL4xChk8ZvIYaYfgB OUnpllaBNXx5Vg+KVU+JZHTbM6+J8qpJJ31Hq279oLqdWZwiMvbmLuh6A4QT3g0psK lMRNDGErpLvAZqd5qu7hw7urhI0u6ldy2Y5EaEQA= Date: Wed, 21 Oct 2026 16:15:06 -0700 From: Andrew Morton To: Hungyu Lin Cc: bsingharora@gmail.com, yang.yang29@zte.com.cn, wang.yaxin@zte.com.cn, wang.yong12@zte.com.cn, xu.xin@linux.dev, jiang.kun2@zte.com.cn, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] delayacct: Preserve delay extrema when aggregating taskstats Message-Id: <20261021161506.7baa42839def1312e177243c@linux-foundation.org> In-Reply-To: <20261021010022.85881-1-dennylin0707@gmail.com> References: <20261021010022.85881-1-dennylin0707@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 21 Oct 2026 01:00:22 +0000 Hungyu Lin wrote: > delayacct_add_tsk() adds each task's statistics to the accumulated TGID > statistics, but overwrites the delay maxima, minima and peak timestamps. > Consequently, the last task determines these fields, and a task with no > recorded delay can erase an earlier task's peak despite a nonzero total. > > Keep the largest maximum and its associated timestamp, and combine the > minima with min_not_zero() since zero denotes an unrecorded delay. Apply > this to CPU delay and the seven delay types handled by UPDATE_DELAY(). > Single-task queries still start with zeroed statistics and retain the > task's values. Looks good, thanks. To improve understandability it would be useful to include a getdelays -d -t before/after example in the changelog.