From: Nitesh Narayan Lal <nitesh@redhat.com>
To: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
peterz@infradead.org
Cc: frederic@kernel.org, mtosatti@redhat.com, juri.lelli@redhat.com,
abelits@marvell.com, bhelgaas@google.com,
linux-pci@vger.kernel.org, rostedt@goodmis.org, mingo@kernel.org,
tglx@linutronix.de, davem@davemloft.net,
akpm@linux-foundation.org, sfr@canb.auug.org.au,
stephen@networkplumber.org, rppt@linux.vnet.ibm.com,
jinyuqi@huawei.com, zhangshaokun@hisilicon.com
Subject: Re: [Patch v4 1/3] lib: Restrict cpumask_local_spread to houskeeping CPUs
Date: Mon, 29 Jun 2020 12:11:25 -0400 [thread overview]
Message-ID: <8054aff1-544d-80de-456f-c3e244233419@redhat.com> (raw)
In-Reply-To: <20200625223443.2684-2-nitesh@redhat.com>
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On 6/25/20 6:34 PM, Nitesh Narayan Lal wrote:
> From: Alex Belits <abelits@marvell.com>
>
> The current implementation of cpumask_local_spread() does not respect the
> isolated CPUs, i.e., even if a CPU has been isolated for Real-Time task,
> it will return it to the caller for pinning of its IRQ threads. Having
> these unwanted IRQ threads on an isolated CPU adds up to a latency
> overhead.
>
> Restrict the CPUs that are returned for spreading IRQs only to the
> available housekeeping CPUs.
>
> Signed-off-by: Alex Belits <abelits@marvell.com>
> Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>
Hi Peter,
I just realized that Yuqi jin's patch [1] that modifies cpumask_local_spread is
lying in linux-next.
Should I do a re-post by re-basing the patches on the top of linux-next?
[1]
https://lore.kernel.org/lkml/1582768688-2314-1-git-send-email-zhangshaokun@hisilicon.com/
> ---
> lib/cpumask.c | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/lib/cpumask.c b/lib/cpumask.c
> index fb22fb266f93..85da6ab4fbb5 100644
> --- a/lib/cpumask.c
> +++ b/lib/cpumask.c
> @@ -6,6 +6,7 @@
> #include <linux/export.h>
> #include <linux/memblock.h>
> #include <linux/numa.h>
> +#include <linux/sched/isolation.h>
>
> /**
> * cpumask_next - get the next cpu in a cpumask
> @@ -205,22 +206,27 @@ void __init free_bootmem_cpumask_var(cpumask_var_t mask)
> */
> unsigned int cpumask_local_spread(unsigned int i, int node)
> {
> - int cpu;
> + int cpu, hk_flags;
> + const struct cpumask *mask;
>
> + hk_flags = HK_FLAG_DOMAIN | HK_FLAG_MANAGED_IRQ;
> + mask = housekeeping_cpumask(hk_flags);
> /* Wrap: we always want a cpu. */
> - i %= num_online_cpus();
> + i %= cpumask_weight(mask);
>
> if (node == NUMA_NO_NODE) {
> - for_each_cpu(cpu, cpu_online_mask)
> + for_each_cpu(cpu, mask) {
> if (i-- == 0)
> return cpu;
> + }
> } else {
> /* NUMA first. */
> - for_each_cpu_and(cpu, cpumask_of_node(node), cpu_online_mask)
> + for_each_cpu_and(cpu, cpumask_of_node(node), mask) {
> if (i-- == 0)
> return cpu;
> + }
>
> - for_each_cpu(cpu, cpu_online_mask) {
> + for_each_cpu(cpu, mask) {
> /* Skip NUMA nodes, done above. */
> if (cpumask_test_cpu(cpu, cpumask_of_node(node)))
> continue;
--
Nitesh
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next prev parent reply other threads:[~2020-06-29 19:12 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-25 22:34 [PATCH v4 0/3] Preventing job distribution to isolated CPUs Nitesh Narayan Lal
2020-06-25 22:34 ` [Patch v4 1/3] lib: Restrict cpumask_local_spread to houskeeping CPUs Nitesh Narayan Lal
2020-06-29 16:11 ` Nitesh Narayan Lal [this message]
2020-07-01 0:32 ` Andrew Morton
2020-07-01 0:47 ` Nitesh Narayan Lal
2021-01-27 11:57 ` Robin Murphy
2021-01-27 12:19 ` Marcelo Tosatti
2021-01-27 12:36 ` Robin Murphy
2021-01-27 13:09 ` Marcelo Tosatti
2021-01-27 13:49 ` Robin Murphy
2021-01-27 14:16 ` Nitesh Narayan Lal
2021-01-28 15:56 ` Thomas Gleixner
2021-01-28 16:33 ` Marcelo Tosatti
[not found] ` <02ac9d85-7ddd-96da-1252-4663feea7c9f@marvell.com>
2021-02-01 17:50 ` [EXT] " Marcelo Tosatti
2021-01-28 16:02 ` Thomas Gleixner
2021-01-28 16:59 ` Marcelo Tosatti
2021-01-28 17:35 ` Nitesh Narayan Lal
2021-01-28 20:01 ` Thomas Gleixner
[not found] ` <d2a4dc97-a9ed-e0e7-3b9c-c56ae46f6608@redhat.com>
[not found] ` <20210129142356.GB40876@fuller.cnet>
2021-01-29 17:34 ` [EXT] " Alex Belits
[not found] ` <18584612-868c-0f88-5de2-dc93c8638816@redhat.com>
2021-02-05 19:56 ` Thomas Gleixner
2021-02-04 18:15 ` Marcelo Tosatti
2021-02-04 18:47 ` Nitesh Narayan Lal
2021-02-04 19:06 ` Marcelo Tosatti
2021-02-04 19:17 ` Nitesh Narayan Lal
2021-02-05 22:23 ` Thomas Gleixner
2021-02-05 22:26 ` Thomas Gleixner
2021-02-07 0:43 ` Nitesh Narayan Lal
2021-02-11 15:55 ` Nitesh Narayan Lal
2021-03-04 18:15 ` Nitesh Narayan Lal
[not found] ` <faa8d84e-db67-7fbe-891e-f4987f106b20@marvell.com>
2021-03-04 23:23 ` [EXT] " Nitesh Narayan Lal
2021-04-06 17:22 ` Jesse Brandeburg
2021-04-07 15:18 ` Nitesh Narayan Lal
2021-04-08 18:49 ` Nitesh Narayan Lal
2021-04-14 16:11 ` Jesse Brandeburg
2021-04-15 22:11 ` Nitesh Narayan Lal
2021-04-29 21:44 ` Nitesh Lal
2021-04-30 1:48 ` Jesse Brandeburg
2021-04-30 13:10 ` Nitesh Lal
2021-04-30 7:10 ` Thomas Gleixner
2021-04-30 16:14 ` Nitesh Lal
2021-04-30 18:21 ` Thomas Gleixner
2021-04-30 21:07 ` Nitesh Lal
2021-05-01 2:21 ` Jesse Brandeburg
2021-05-03 13:15 ` Nitesh Lal
2020-06-25 22:34 ` [Patch v4 2/3] PCI: Restrict probe functions to housekeeping CPUs Nitesh Narayan Lal
2020-06-25 22:34 ` [Patch v4 3/3] net: Restrict receive packets queuing " Nitesh Narayan Lal
2020-06-26 11:14 ` Peter Zijlstra
2020-06-26 17:20 ` David Miller
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