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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 358EAC02196 for ; Thu, 6 Feb 2025 08:29:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9DE5128000E; Thu, 6 Feb 2025 03:29:21 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 98DB7280005; Thu, 6 Feb 2025 03:29:21 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 87C1C28000E; Thu, 6 Feb 2025 03:29:21 -0500 (EST) 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 6A956280005 for ; Thu, 6 Feb 2025 03:29:21 -0500 (EST) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id E5198B1BA9 for ; Thu, 6 Feb 2025 08:29:20 +0000 (UTC) X-FDA: 83088845280.30.894D485 Received: from mail-pl1-f171.google.com (mail-pl1-f171.google.com [209.85.214.171]) by imf17.hostedemail.com (Postfix) with ESMTP id F2D2B40003 for ; Thu, 6 Feb 2025 08:29:18 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=AIw2byAh; dmarc=pass (policy=none) header.from=chromium.org; spf=pass (imf17.hostedemail.com: domain of senozhatsky@chromium.org designates 209.85.214.171 as permitted sender) smtp.mailfrom=senozhatsky@chromium.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1738830559; a=rsa-sha256; cv=none; b=Jn0CgkVfqjr01VWjZIy6cNKJbNaeIK0pPpoDXD4d8wJcraAiXntOkI15d90F5d8n0sdt5H 7FkGs4Fty4cfroM3m0DmLqrl6KiR0OW1FAK5VNFJYtu4edaRJiyFxR2KyuTlv+aB99S1Q0 h6B0qErtt3FEiQ/Jj0vNGcaIcqbf30c= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=AIw2byAh; dmarc=pass (policy=none) header.from=chromium.org; spf=pass (imf17.hostedemail.com: domain of senozhatsky@chromium.org designates 209.85.214.171 as permitted sender) smtp.mailfrom=senozhatsky@chromium.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1738830559; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=hTMiuwQxnZL8hN7cBfXpXr8CeaByDASFkZFzoKs1uVw=; b=IImduOdo+wJqsHiOdLVI9J8GODfH1uvW/FAue2cJj18f6+ESPJbt/r8zbzY9um8Ze5rRTS LXTu7wEsttx6l7dcP9h+gw6Q4QXnKA7b/TkJP4alXM8bGeVGOVdflZzdl9RrC0zFQVfFoI dCVIQlAgg0RX5SO/+x1BVuuPxMzs/Pg= Received: by mail-pl1-f171.google.com with SMTP id d9443c01a7336-21670dce0a7so15664905ad.1 for ; Thu, 06 Feb 2025 00:29:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1738830558; x=1739435358; darn=kvack.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=hTMiuwQxnZL8hN7cBfXpXr8CeaByDASFkZFzoKs1uVw=; b=AIw2byAhKV2IDBAB4sdW3dDveI9h6AqdyDFe3bWHjqw48IqsZiqV5b+S+gc8yKiINU 3RxEpNh2ppPilx7GwhpmU45KPPdnf8n4iKhh5vtPYysf1acBuAi2P5CFj+QJh0fH34yl 298rBFCgQwJMT2kPvgqMhELYAXWOGg50CKl8E= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1738830558; x=1739435358; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=hTMiuwQxnZL8hN7cBfXpXr8CeaByDASFkZFzoKs1uVw=; b=Ipons+Xc1HxEWAl1hIwQXqBpAYenQQ+/rORe2GBPL6sTibjA3Kn89R74k1K8YcVlww 1b6wnHZN60QCnl1vxHEOItyIl87ZaruwqdjkzBqB8Om5emDCJX8OEDjUtVJIyip1QJo2 pVG4Z/OGMcgUdEdfvyYEWkQPDYXAZSzCj8oOgJhBsp0V8JeZESALwrgjcxmvIakz8egD E9SOlnjksr1+GtG5qq99H1av17rpFWdkBpWNGZzsprRieTtzkCbE8Gs4hzTvQifwMJlh FU+610TfMHejSxhExJ1QjikQGXJ4bx7167d+gLUZvtsrlCEJJcupfovJAVLDE1C/c7cg UQYQ== X-Forwarded-Encrypted: i=1; AJvYcCW+fN/dluxsJFR36XFaN8ACM0Ts9i6qh0m077JAcT3bUmQz7VSXO0fUZWAfRfMK1yep6JuPGUk7MQ==@kvack.org X-Gm-Message-State: AOJu0YynvlA1/u1ynNBpcS/xHUDdyYWy1YF7R15PufGwYXKrooYVtdcW htt6A+ZLMLJo3tewyeMpjB+OUN7qOrLWTohzCADwYY+2K+4xEKCGZxW0SxRL3A== X-Gm-Gg: ASbGncuLijpgKhzUEg0pQNuqfdQ6RikBJBmcknfU1bos8wtr7avVyPsQSTFdOKzIvUO MjyJ6+eR/d2rAIN0q1x8EreQSW1qh8WiHscDhMKpRkrPdZD3WCzTowxFILyzNn+tkLltg3NupWi LHfob0DB8Ha6RBtGWnfWZL9SCPXgEdb9rGZ+ISH9t5N6f7JH7R3Ov0KHBZIRCZNgTWNIL3YXpO+ fDFqqHanUoinq382erjAi9WktAfe4I8Pvt6+r53VuRSKdDmbMDfMB3xzWGUcu1o66LAU3lKwnUo RYJcGKqa0/xBRkKfzoQ= X-Google-Smtp-Source: AGHT+IHKu+/kkxv3nh8DeKbuRIC1L0v/M07cqILr0sFaf+TajiM4acbw0AF9YRCI5qd+AEJ/u4FMDg== X-Received: by 2002:a17:902:ce8b:b0:21f:3e2d:7d41 with SMTP id d9443c01a7336-21f3e2d8011mr8566605ad.11.1738830557712; Thu, 06 Feb 2025 00:29:17 -0800 (PST) Received: from google.com ([2401:fa00:8f:203:28ab:cea4:aa8a:127a]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-21f3653baa8sm7133985ad.73.2025.02.06.00.29.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Feb 2025 00:29:17 -0800 (PST) Date: Thu, 6 Feb 2025 17:29:12 +0900 From: Sergey Senozhatsky To: Sebastian Andrzej Siewior Cc: Sergey Senozhatsky , Andrew Morton , Minchan Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hillf Danton , Mike Galbraith Subject: Re: [PATCHv4 01/17] zram: switch to non-atomic entry locking Message-ID: References: <20250131090658.3386285-1-senozhatsky@chromium.org> <20250131090658.3386285-2-senozhatsky@chromium.org> <20250131145536.d7a0483331b0ebfde80a5754@linux-foundation.org> <20250206073803.c2tiyIq6@linutronix.de> <46ttdyaiweca7qou2t3mx5jy7hefg3htrv4covt5htcex7zaq4@p6is3ukmtbhy> <20250206081326.xMa5Z5oJ@linutronix.de> <20250206082635.dZ1qhyhU@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250206082635.dZ1qhyhU@linutronix.de> X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: F2D2B40003 X-Stat-Signature: dr9btrnecr8mrd5mif7td7qebyus3egr X-HE-Tag: 1738830558-655625 X-HE-Meta: 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 7E0jTrDC drsG0bAPELo6QZpxSEiKwyRu8e8IYSBTuSoJaHDRLJlUZmo26U/ZaBYZHaoPR7T/DxNydE70MFXqkKBhwUpXFhJsioB8sgK2HjxO9rpQ08kGbUexCgH52QaX1Lzc0l6vczpbNaUIwwLsUo2poiNsV/vDsz8UJE2vdKtfXHvSNYqZ5G26CPwUDN4/aDxR2VMX4wkZGqsD2LZL+b8/J5abKonHgCpNN++tyhE8hSXW78a7vHMQGagHRkY9qNwu9ApijtZciqrrJNGGjIJ0HeBA8oSsaxrAg+8kiJUbuDDUeNDNRP/51JWIIC0UdqX7/3utdjNtblpgKVlFj/6yZ4ECdqupGXcKxXKNwr5552pQ5tJVnb10= X-Bogosity: Ham, tests=bogofilter, spamicity=0.009514, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On (25/02/06 09:26), Sebastian Andrzej Siewior wrote: > On 2025-02-06 17:17:41 [+0900], Sergey Senozhatsky wrote: > > > Okay. So there are requirements for the sleeping lock. A mutex isn't > > > fitting the requirement because it is too large I guess. > > > > Correct. > > I would nice to state this why a generic locking implementation can not > be used. From what I have seen it should play along with RT nicely. Will do. > > > > wait_on_bit_lock() has might_sleep(). > > > > > > My point exactly. This makes the WARN_ON_ONCE() obsolete. > > > > Right, might_sleep() can be disabled, as far as I understand, > > via CONFIG_DEBUG_ATOMIC_SLEEP, unlike WARN_ON_ONCE(). But I > > can drop it and then just rely on might_sleep(), should be > > enough. > > It should be enough. mutex_lock(), down() and so on relies solely on it. > As I said, preemptible() only works on preemptible kernels if it comes > to the preemption counter on and !preemptible kernels with enabled > debugging. Ack.