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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 089F1CD5BAF for ; Thu, 21 May 2026 17:22:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:References:In-Reply-To: Subject:Cc:To:From:Message-ID:Date:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=AlzKy8zLiXVW3OOWreCz0uBaIrjhWNSN2snhmHYvFec=; b=dCIe8kheW1krpITI7MsBxt3sLo 6ARGanOch+bHBNCIjgIZQx0m0uwLQ+be26UOaED2p+nda7cBuy7prowykUgreuEgAKJL1U74BelG8 zhigbvlB3+f7OweftgbywrETkjOutSqbki9u7JVK4ORk8Y/GsmR1DkjYmoLjU9CStgXmfz+yU1D7F a81T/MufeJWS3/c+mDmBYVHjRfxXgk/5C10JpsTevV0YWfx/CH16twvbwzemNZCHD3L6IszfeROGw EGRArvceNVdG00pK73zjBse0fi0MTN888Tyt+SKYBU0yMCiZN+11h64OpBlnou7+HuTOVxf4XaCCS gxNzSSlw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wQ76P-00000008cl2-2knj; Thu, 21 May 2026 17:22:33 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wQ76M-00000008ckM-3lME for linux-arm-kernel@lists.infradead.org; Thu, 21 May 2026 17:22:33 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 34314438D5; Thu, 21 May 2026 17:22:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E29FD1F000E9; Thu, 21 May 2026 17:22:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779384150; bh=AlzKy8zLiXVW3OOWreCz0uBaIrjhWNSN2snhmHYvFec=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=RKJIuj4G6CxC3qvs89BfWMbcUoDSq208cSVcu+n+piDs6pYGX3tDnKJJp+wyEpHQI zfUxFkRf6rqU3CJqN1pP6wxooh9U3NjM+1ynKMmwDjMJ2wuEhEaWjBQRv2GCiudUKk tJuHFTXznYMDXkaP/pjJvyWq1OAXTOoYM2k/2JCDJC1pTk8+4K8wfZ7e7rZAUC7nRn QnMWl0LV1raXD5Fb2tTHOkjsG8/RXyC7x1eS47hWpdOdJc3MnWfetSleiaOD6JugM7 BJE5HlqjmfJDsh8jjAnbWtXKeRzJcN3q9opWMQRnDTlT+jVbgUCD1I3eFZAWBMIFmy 6+n2MkU4nQvrA== Date: Thu, 21 May 2026 07:22:29 -1000 Message-ID: <0ea50f62b8255cc0ff1a96206096746a@kernel.org> From: Tejun Heo To: Andrea Righi Cc: David Vernet , Changwoo Min , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Kumar Kartikeya Dwivedi , Peter Zijlstra , Catalin Marinas , Will Deacon , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Andrew Morton , David Hildenbrand , Mike Rapoport , Emil Tsalapatis , sched-ext@lists.linux.dev, bpf@vger.kernel.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 7/8] sched_ext: Sub-allocator over kernel-claimed BPF arena pages In-Reply-To: References: <20260520235052.4180316-1-tj@kernel.org> <20260520235052.4180316-8-tj@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260521_102230_957087_469EFD2D X-CRM114-Status: UNSURE ( 9.75 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hello, On Thu, May 21, 2026 at 09:56:05AM +0200, Andrea Righi wrote: > IIUC, since @page_cnt is sized to cover @size and the new chunk is added empty > to the pool, gen_pool_alloc() here should always succeed. Should we do: > > if (WARN_ON_ONCE(!kern_va)) > return NULL; > > to catch potential logical bugs / future concurrency / exotic configurations? Good point. It works for a single caller, but a concurrent one could drain the new chunk between grow and retry. I'll switch it to a loop. Thanks. -- tejun