From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH for-5.15 v2] io_uring: consider cgroup setting when binding sqpoll cpu Date: Fri, 27 Aug 2021 08:18:48 -0600 Message-ID: <0988b0dc-232f-80cd-c984-2364c0dee69f@kernel.dk> References: <20210827141315.235974-1-haoxu@linux.alibaba.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=uZsEs/8kjOigJb/9CIkKujcCvyTVtquxdPpsZWziM2Y=; b=nDreCI/xOmeEf6Q9hlgH9sBVSs7+vcBblHdWls/D5MIdQYK11J66jrdchuffKwpj8C 1o3lk6jlwlTOK56KNKiiiyOjFoKruwTSoajZTB3fuo9zVy3pPU6vWUOALr3jpwMlUK8f 260rhgUH086HtMkMBvnlnRTPFhhs4JZlqGZDSXjmdqcoBgh0IsA6Yjrpxcxsm+716fuz 5R+Maws6hyrjzYhIQomTkgmne+0ovh8TRXZhp8+XBN0W+abiP6wKq20Gy0NKuCFAOdce BIJC94PeCehqW8tMPlzD7Xxe2lRDWlZoc7cKR2d/cICtbQ/FYlr4DEfmMhn+2CkRaO1s 7eqA== In-Reply-To: <20210827141315.235974-1-haoxu@linux.alibaba.com> Content-Language: en-US List-ID: Content-Type: text/plain; charset="us-ascii" To: Hao Xu , Zefan Li , Tejun Heo , Johannes Weiner , Pavel Begunkov Cc: io-uring@vger.kernel.org, cgroups@vger.kernel.org, Joseph Qi On 8/27/21 8:13 AM, Hao Xu wrote: > Since sqthread is userspace like thread now, it should respect cgroup > setting, thus we should consider current allowed cpuset when doing > cpu binding for sqthread. In general, this looks way better than v1. Just a few minor comments below. > @@ -7000,6 +7001,16 @@ static bool io_sqd_handle_event(struct io_sq_data *sqd) > return did_sig || test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state); > } > > +static int io_sq_bind_cpu(int cpu) > +{ > + if (!test_cpu_in_current_cpuset(cpu)) > + pr_warn("sqthread %d: bound cpu not allowed\n", current->pid); > + else > + set_cpus_allowed_ptr(current, cpumask_of(cpu)); > + > + return 0; > +} This should not be triggerable, unless the set changes between creation and the thread being created. Hence maybe the warn is fine. I'd probably prefer terminating the thread at that point, which would result in an -EOWNERDEAD return when someone attempts to wake the thread. Which is probably OK, as we really should not hit this path. > diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h > index 04c20de66afc..fad77c91bc1f 100644 > --- a/include/linux/cpuset.h > +++ b/include/linux/cpuset.h > @@ -116,6 +116,8 @@ static inline int cpuset_do_slab_mem_spread(void) > > extern bool current_cpuset_is_being_rebound(void); > > +extern bool test_cpu_in_current_cpuset(int cpu); > + > extern void rebuild_sched_domains(void); > > extern void cpuset_print_current_mems_allowed(void); > @@ -257,6 +259,11 @@ static inline bool current_cpuset_is_being_rebound(void) > return false; > } > > +static inline bool test_cpu_in_current_cpuset(int cpu) > +{ > + return false; > +} > + > static inline void rebuild_sched_domains(void) > { > partition_sched_domains(1, NULL, NULL); > diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c > index adb5190c4429..a63c27e9430e 100644 > --- a/kernel/cgroup/cpuset.c > +++ b/kernel/cgroup/cpuset.c > @@ -1849,6 +1849,17 @@ bool current_cpuset_is_being_rebound(void) > return ret; > } > > +bool test_cpu_in_current_cpuset(int cpu) > +{ > + bool ret; > + > + rcu_read_lock(); > + ret = cpumask_test_cpu(cpu, task_cs(current)->effective_cpus); > + rcu_read_unlock(); > + > + return ret; > +} > + > static int update_relax_domain_level(struct cpuset *cs, s64 val) > { > #ifdef CONFIG_SMP In terms of review and so forth, I'd split this into a prep patch. Then patch 2 just becomes the io_uring consumer of it. -- Jens Axboe