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client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C Received: from SATLEXMB04.amd.com (165.204.84.17) by SJ5PEPF000001EB.mail.protection.outlook.com (10.167.242.199) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.8489.16 via Frontend Transport; Wed, 26 Feb 2025 17:56:43 +0000 Received: from [10.252.195.191] (10.180.168.240) by SATLEXMB04.amd.com (10.181.40.145) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Wed, 26 Feb 2025 11:56:38 -0600 Message-ID: Date: Wed, 26 Feb 2025 23:26:35 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] pipe_read: don't wake up the writer if the pipe is still full To: Oleg Nesterov CC: Manfred Spraul , Linus Torvalds , Christian Brauner , David Howells , WangYuli , , , "K Prateek Nayak" , "Shenoy, Gautham Ranjal" , , References: <20250102140715.GA7091@redhat.com> <20250224142329.GA19016@redhat.com> <20250225115736.GA18523@redhat.com> <2a0a8e1e-1c37-4655-8a82-54681b2a83ae@amd.com> <20250226113845.GB8995@redhat.com> Content-Language: en-US From: "Sapkal, Swapnil" In-Reply-To: <20250226113845.GB8995@redhat.com> Content-Type: text/plain; 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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Feb 2025 17:56:43.1432 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: b8993515-d929-48d7-7245-08dd568eede4 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: SJ5PEPF000001EB.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH3PR12MB8258 Hi Oleg, On 2/26/2025 5:08 PM, Oleg Nesterov wrote: > Thanks Sapkal! > > I'll try to think. Meanwhile, > > On 02/26, Sapkal, Swapnil wrote: >> >> Exact command with parameters is >> >> /usr/bin/hackbench -g 16 -f 20 --threads --pipe -l 100000 -s 100 > > Can you reproduce with "--process" rather than "--threads" ? > I was able to reproduce the issue with processes also. Total 33 processes were sleeping out of which 20 were readers and 13 were writers. The stack trace for main hackbench process is as follows: [<0>] do_wait+0xb5/0x110 [<0>] kernel_wait4+0xb2/0x150 [<0>] __do_sys_wait4+0x89/0xa0 [<0>] __x64_sys_wait4+0x20/0x30 [<0>] x64_sys_call+0x1bf7/0x2140 [<0>] do_syscall_64+0x6f/0x110 [<0>] entry_SYSCALL_64_after_hwframe+0x76/0x7e I am trying to reproduce the issue with suggestions by Mateusz. > Oleg. > -- Thanks and Regards, Swapnil