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[73.241.150.58]) by smtp.gmail.com with ESMTPSA id d22sm2789006pfd.42.2020.08.12.08.19.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 12 Aug 2020 08:19:59 -0700 (PDT) Subject: Re: [PATCH net] net: accept an empty mask in /sys/class/net/*/queues/rx-*/rps_cpus To: peterz@infradead.org, =?UTF-8?Q?Maciej_=c5=bbenczykowski?= Cc: Eric Dumazet , "David S . Miller" , netdev , Eric Dumazet , Alex Belits , Nitesh Narayan Lal References: <20200812013440.851707-1-edumazet@google.com> <20200812080049.GH2674@hirez.programming.kicks-ass.net> From: Eric Dumazet Message-ID: Date: Wed, 12 Aug 2020 08:19:57 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200812080049.GH2674@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 8/12/20 1:00 AM, peterz@infradead.org wrote: > On Tue, Aug 11, 2020 at 06:45:23PM -0700, Maciej Żenczykowski wrote: >> On Tue, Aug 11, 2020 at 6:34 PM Eric Dumazet wrote: >> >>> We must accept an empty mask in store_rps_map(), or we are not able >>> to disable RPS on a queue. >>> >>> Fixes: 07bbecb34106 ("net: Restrict receive packets queuing to >>> housekeeping CPUs") >>> Signed-off-by: Eric Dumazet >>> Reported-by: Maciej Żenczykowski >>> Cc: Alex Belits >>> Cc: Nitesh Narayan Lal >>> Cc: Peter Zijlstra (Intel) >>> --- >>> net/core/net-sysfs.c | 12 +++++++----- >>> 1 file changed, 7 insertions(+), 5 deletions(-) >>> >>> diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c >>> index >>> 9de33b594ff2693c054022a42703c90084122444..efec66fa78b70b2fe5b0a5920317eb1d0415d9e3 >>> 100644 >>> --- a/net/core/net-sysfs.c >>> +++ b/net/core/net-sysfs.c >>> @@ -757,11 +757,13 @@ static ssize_t store_rps_map(struct netdev_rx_queue >>> *queue, >>> return err; >>> } >>> >>> - hk_flags = HK_FLAG_DOMAIN | HK_FLAG_WQ; >>> - cpumask_and(mask, mask, housekeeping_cpumask(hk_flags)); >>> - if (cpumask_empty(mask)) { >>> - free_cpumask_var(mask); >>> - return -EINVAL; >>> + if (!cpumask_empty(mask)) { >>> + hk_flags = HK_FLAG_DOMAIN | HK_FLAG_WQ; >>> + cpumask_and(mask, mask, housekeeping_cpumask(hk_flags)); >>> + if (cpumask_empty(mask)) { >>> + free_cpumask_var(mask); >>> + return -EINVAL; >>> + } >>> } > > Ah indeed! Sorry about that. > > Acked-by: Peter Zijlstra (Intel) > No worries, thanks for the review guys. We probably should add a test doing something like echo ffffffff >/sys/class/net/lo/queues/rx-0/rps_cpus echo 0 >/sys/class/net/lo/queues/rx-0/rps_cpus