From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753887AbdJRN1s (ORCPT ); Wed, 18 Oct 2017 09:27:48 -0400 Received: from mail-qk0-f194.google.com ([209.85.220.194]:47264 "EHLO mail-qk0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753821AbdJRNZb (ORCPT ); Wed, 18 Oct 2017 09:25:31 -0400 X-Google-Smtp-Source: ABhQp+R1Nl8fl0XNZKi2qc4s3Q8JJ9ai08fxcgoOPxaj8aMXgfLedigOD+jW4LLLHZGtfXLkPR4JlA== Date: Wed, 18 Oct 2017 06:25:26 -0700 From: Tejun Heo To: Daniel Borkmann Cc: davem@davemloft.net, ast@kernel.org, john.fastabend@gmail.com, mark.rutland@arm.com, richard@nod.at, sp3485@columbia.edu, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Dennis Zhou Subject: Re: [PATCH net 0/3] Fix for BPF devmap percpu allocation splat Message-ID: <20171018132526.GC1302522@devbig577.frc2.facebook.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Daniel. (cc'ing Dennis) On Tue, Oct 17, 2017 at 04:55:51PM +0200, Daniel Borkmann wrote: > The set fixes a splat in devmap percpu allocation when we alloc > the flush bitmap. Patch 1 is a prerequisite for the fix in patch 2, > patch 1 is rather small, so if this could be routed via -net, for > example, with Tejun's Ack that would be good. Patch 3 gets rid of > remaining PCPU_MIN_UNIT_SIZE checks, which are percpu allocator > internals and should not be used. > > Thanks! > > Daniel Borkmann (3): > mm, percpu: add support for __GFP_NOWARN flag This looks fine. > bpf: fix splat for illegal devmap percpu allocation > bpf: do not test for PCPU_MIN_UNIT_SIZE before percpu allocations These look okay too but if it helps percpu allocator can expose the maximum size / alignment supported to take out the guessing game too. Also, the reason why PCPU_MIN_UNIT_SIZE is what it is is because nobody needed anything bigger. Increasing the size doesn't really cost much at least on 64bit archs. Is that something we want to be considering? Thanks. -- tejun