From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C0C1CCD98ED for ; Thu, 18 Jun 2026 07:21:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 96EE46B0088; Thu, 18 Jun 2026 03:21:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 920586B008A; Thu, 18 Jun 2026 03:21:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 837566B008C; Thu, 18 Jun 2026 03:21:17 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 5A4386B0088 for ; Thu, 18 Jun 2026 03:21:17 -0400 (EDT) Received: from smtpin30.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id D47F21C2DAD for ; Thu, 18 Jun 2026 07:21:16 +0000 (UTC) X-FDA: 84892187352.30.3C3111B Received: from out-177.mta0.migadu.com (out-177.mta0.migadu.com [91.218.175.177]) by imf13.hostedemail.com (Postfix) with ESMTP id 8E85520002 for ; Thu, 18 Jun 2026 07:21:13 +0000 (UTC) Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=HySLrnYz; spf=pass (imf13.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.177 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1781767275; 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=GtlEMfVTH63Oa0whvIFuEXdWiCj3k8WGdr0XfDgRc4E=; b=BGZiL+WiptC9gPRj8nP4CkXc/OOV6dbbvQ72Qc8EIYMqDAGIIlkkrl/xbMylo6rbF/EY5t 8e+6oQhCjyxhf2PjQb8rbao3x++twuqb/L4SnxJ16767eueDPoFIKAv02dThZHaggSaqOB 7UhXcml2Cq1s3+P10EOMboZA3OVpjkM= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=HySLrnYz; spf=pass (imf13.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.177 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1781767275; b=T+bgYFLfgHYkM/QIekXnwnPBOCMlwqovXKG/+WLvnYYuofeV1eA2xYie5RcvuLsZqHAQtn uoL6CIDl/2qzB0QtF3IVb0kiBSllqX6UFO7th7eZpowNzLMIEXe7k88P9C097fNtbKLkjL W1vsRWKfhwauv66tw7wR3iZ8QS3jEHM= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1781767271; h=from:from: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; bh=GtlEMfVTH63Oa0whvIFuEXdWiCj3k8WGdr0XfDgRc4E=; b=HySLrnYzumRMbNCiHXgZaMm3OwZfCXXP0goIvaNtrjiv774vw6wDkQWW4+fesHYnDoI4lj I23WYJcgTdhtL6qSuIc+TOeVWXkAFWSqfXmy7rU34K5BnOaH11fqhnHsSNee2+AHljjXev B+iBecDkfQDra1ji3AzrFspfDEiOl2A= From: Lance Yang To: zhen.ni@easystack.cn Cc: akpm@linux-foundation.org, vbabka@kernel.org, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Lance Yang Subject: Re: [PATCH v10 3/4] tools/mm: add page_owner_filter userspace tool Date: Thu, 18 Jun 2026 15:21:03 +0800 Message-Id: <20260618072103.92397-1-lance.yang@linux.dev> In-Reply-To: <20260618035750.3724613-4-zhen.ni@easystack.cn> References: <20260618035750.3724613-4-zhen.ni@easystack.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 8E85520002 X-Stat-Signature: q3qc9ugomh1n3efo5rdjih7hi9yjpteg X-Rspam-User: X-HE-Tag: 1781767273-240356 X-HE-Meta: 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 48mPI5Wv mHmw8zfeA6B3F/W6KBNwP8D1RuXj0Kuok8Dzz4WjeUICUgRC/orTKVS9Uh6FHHDX37rh/QJRpXrLzvZuGEiSJXasmcZ5pxLn2ZOXPTJqADvAjcz+EicRoLdlBx4FZsozVPY5YY2T7rNmTM/jXZp4t5YFs2Xpf6PDTtV9PYBwCLBwn87WTSm/qKFPiZnCIR4kH0dGP2uLH3mMws9uBo6JEsbWjXw/ace8nsG1EUvqqawZDXflojBqDNaOd7FW7WvGqC8ez Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Jun 18, 2026 at 11:57:49AM +0800, Zhen Ni wrote: [...] >+ /* Read and display filtered output */ >+ ret = 0; >+ while ((ret = read(fd, buf, sizeof(buf))) > 0) { >+ size_t written = fwrite(buf, 1, ret, output); >+ >+ if (written != (size_t)ret) { >+ if (errno == EPIPE) { Hmm ... does this work without handling SIGPIPE first? With something like: $ ./page_owner_filter -m handle | head The writer can be killed by SIGPIPE before fwrite() returns EPIPE no? so this branch would usually not be reached ... >+ /* Pipe closed, treat as success */ >+ ret = 0; >+ goto out; >+ } >+ perror("write output"); >+ ret = -1; >+ goto out; >+ } >+ } >+ >+ if (ret < 0) { >+ perror("read page_owner"); >+ goto out; >+ } >+ >+ if (fflush(output)) { fflush() can also be where the broken pipe is reported, but still treats EPIPE as an error ... Shouldn't we ignore/handle SIGPIPE and treat EPIPE from both fwrite() and fflush() as succes? Cheers, Lance >+ perror("flush output"); >+ ret = -1; >+ } >+ >+out: >+ close(fd); >+ if (output != stdout) >+ fclose(output); >+ return ret < 0 ? 1 : 0; >+} >-- >2.20.1 > >