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[73.219.103.14]) by smtp.gmail.com with ESMTPSA id n24-20020ac86758000000b0031ed8ef7982sm9715714qtp.22.2022.07.19.16.43.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 19 Jul 2022 16:43:47 -0700 (PDT) Message-ID: <7462e934-f746-eef7-ff92-0eeb8cc08b82@gmail.com> Date: Tue, 19 Jul 2022 19:43:46 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH v4 00/34] Printbufs - new data structure for building strings Content-Language: en-US To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, pmladek@suse.com, enozhatsky@chromium.org, linux@rasmusvillemoes.dk, willy@infradead.org References: <20220620004233.3805-1-kent.overstreet@gmail.com> <20220719191522.4002a5fb@gandalf.local.home> From: Kent Overstreet In-Reply-To: <20220719191522.4002a5fb@gandalf.local.home> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=NPnJjmSv; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf28.hostedemail.com: domain of kent.overstreet@gmail.com designates 209.85.222.171 as permitted sender) smtp.mailfrom=kent.overstreet@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1658274229; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=ptG1sWGcXWUClftC0HzZgw9GrQMqzL3RYHOJxThs0Bs=; b=zlPHutKOzXtk4WrvjYSBwuZsnnZ7eo43AFGOFO4d2RyzTa+bXJxXp6KAo7Hg0G6u45O66C wUIIA5gPX/E6GnDVbR43TTu0DccCagZ5/pldiidmy1YS4a1u5JDjGrJF/fymIjG0K9sCaX jp+N40zmnOKsJ2d7jtMz8WY0LCdE2B4= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1658274229; a=rsa-sha256; cv=none; b=CLl9yQEh6AFfVUKvxfZ0oni5pvHSqmOkUd4GQS/z6TTDYrA6S1CuvCY/9yCaUXjjxAmM1O 5yTiFEQErqDXidb5m8IXvIgCfDn+RMxCyN3iD7A3bSY5F7cyDx2bDQ7RmMtZMabhtQxk3p qzrdfjguy4RoAseoc5o8yr2O0TB5mXw= X-Rspamd-Queue-Id: 1F389C0014 Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=NPnJjmSv; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf28.hostedemail.com: domain of kent.overstreet@gmail.com designates 209.85.222.171 as permitted sender) smtp.mailfrom=kent.overstreet@gmail.com X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: 3ki5abce9s4mdsweuczgs3r4hwx9ofnt X-HE-Tag: 1658274228-774456 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 7/19/22 19:15, Steven Rostedt wrote: > On Sun, 19 Jun 2022 20:41:59 -0400 > Kent Overstreet wrote: > >> Core idea: Wouldn't it be nice if we had a common data structure and calling >> convention for outputting strings? > > Because seq_buf gives us this already, the cover letter really just needs > to state exactly what the benefit is to replace seq_buf with printbuf (and > why seq_buf can not be simply extended to do some extra features). - seq_buf has the wrong semantics on overflow for what vsnprintf needs. - seq_buf is somewhat unnecessarily coupled to tracing needs - the readpos member has nothing to do with outputting formatting strings, and some of the pretty-printers are tracing specific and don't really belong in a generic pretty-printing library. And, when I tried to talk to you about changing seq_buf to be more suitable you didn't respond - you just dropped off the IRC discussion we were having. > > I just applied your series and ran the tracing selftests and several of > them failed. > > # cd tools/testing/selftests/ftrace/ > # ./ftracetest Thank you for telling me where to find the tests. It would've saved us some back and forth (and I could've gotten on this sooner) if you'd responded when I asked before. It may seem like the perfectly natural place to look to you - who works on the code - but to someone who works on a variety of subsystems, each of which puts their test code (if they have any!) in a different place, it wasn't. However, when I enabled all the tracing kernel config options, your tests are now failing to run at all with: db_root: cannot open: /etc/target So now I've got to debug your tests, too. Gah.