From: Usama Arif <usama.arif@bytedance.com>
To: Thomas Gleixner <tglx@linutronix.de>,
dwmw2@infradead.org, kim.phillips@amd.com
Cc: arjan@linux.intel.com, mingo@redhat.com, bp@alien8.de,
dave.hansen@linux.intel.com, hpa@zytor.com, x86@kernel.org,
pbonzini@redhat.com, paulmck@kernel.org,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
rcu@vger.kernel.org, mimoja@mimoja.de, hewenliang4@huawei.com,
thomas.lendacky@amd.com, seanjc@google.com,
pmenzel@molgen.mpg.de, fam.zheng@bytedance.com,
punit.agrawal@bytedance.com, simon.evans@bytedance.com,
liangma@liangbit.com, David Woodhouse <dwmw@amazon.co.uk>
Subject: Re: [External] Re: [PATCH v8 6/9] x86/smpboot: Support parallel startup of secondary CPUs
Date: Thu, 9 Feb 2023 20:37:58 +0000 [thread overview]
Message-ID: <b7643e5b-520d-0c4c-75ea-0cb65a2dbd42@bytedance.com> (raw)
In-Reply-To: <87r0uy1ysm.ffs@tglx>
On 09/02/2023 18:25, Thomas Gleixner wrote:
> On Thu, Feb 09 2023 at 15:41, Usama Arif wrote:
>>
>> +static bool do_parallel_bringup = true;
>
> Wants to be __ro_after_init
>
>> +static int __init no_parallel_bringup(char *str)
>> +{
>> + do_parallel_bringup = false;
>> +
>> + return 0;
>> +}
>> +early_param("no_parallel_bringup", no_parallel_bringup);
>
> Lacks an entry in Documentation/admin/kernel-parameters.txt
>
> Thanks,
>
> tglx
Thanks, I will add the below to next revision. Its quite minor so will
wait for more comments and MTRR question to be resolved, unless told to
send next revision with this diff only.
diff --git a/Documentation/admin-guide/kernel-parameters.txt
b/Documentation/admin-guide/kernel-parameters.txt
index 6cfa6e3996cf..d3696c9316f1 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3830,6 +3830,9 @@
noreplace-smp [X86-32,SMP] Don't replace SMP instructions
with UP alternatives
+ no_parallel_bringup
+ [X86,SMP] Disables parallel brinugp of secondary
cores.
+
noresume [SWSUSP] Disables resume and restores original swap
space.
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 3ec5182d9698..fecd934e72fb 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -813,7 +813,7 @@ static int __init cpu_init_udelay(char *str)
}
early_param("cpu_init_udelay", cpu_init_udelay);
-static bool do_parallel_bringup = true;
+static bool do_parallel_bringup __ro_after_init = true;
static int __init no_parallel_bringup(char *str)
{
next prev parent reply other threads:[~2023-02-09 20:38 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-09 15:41 [PATCH v8 0/9] Parallel CPU bringup for x86_64 Usama Arif
2023-02-09 15:41 ` [PATCH v8 1/9] x86/apic/x2apic: Allow CPU cluster_mask to be populated in parallel Usama Arif
2023-02-09 15:41 ` [PATCH v8 2/9] cpu/hotplug: Move idle_thread_get() to <linux/smpboot.h> Usama Arif
2023-02-09 15:41 ` [PATCH v8 3/9] cpu/hotplug: Add dynamic parallel bringup states before CPUHP_BRINGUP_CPU Usama Arif
2023-02-09 15:41 ` [PATCH v8 4/9] x86/smpboot: Reference count on smpboot_setup_warm_reset_vector() Usama Arif
2023-02-09 15:41 ` [PATCH v8 5/9] x86/smpboot: Split up native_cpu_up into separate phases and document them Usama Arif
2023-02-09 15:41 ` [PATCH v8 6/9] x86/smpboot: Support parallel startup of secondary CPUs Usama Arif
2023-02-09 18:25 ` Thomas Gleixner
2023-02-09 20:37 ` Usama Arif [this message]
2023-02-09 15:41 ` [PATCH v8 7/9] x86/smpboot: Send INIT/SIPI/SIPI to secondary CPUs in parallel Usama Arif
2023-02-09 15:41 ` [PATCH v8 8/9] x86/mtrr: Avoid repeated save of MTRRs on boot-time CPU bringup Usama Arif
2023-02-09 18:31 ` Thomas Gleixner
2023-02-09 20:32 ` [External] " Usama Arif
2023-02-09 20:37 ` David Woodhouse
2023-02-09 23:50 ` Thomas Gleixner
2023-02-10 8:55 ` David Woodhouse
2023-02-13 15:19 ` Usama Arif
2023-02-13 20:42 ` Thomas Gleixner
2023-02-09 15:41 ` [PATCH v8 9/9] x86/smpboot: Serialize topology updates for secondary bringup Usama Arif
2023-02-13 20:43 ` Thomas Gleixner
2023-02-13 20:53 ` David Woodhouse
2023-02-13 22:30 ` [External] " Usama Arif
2023-02-14 6:57 ` David Woodhouse
2023-02-10 4:11 ` [PATCH v8 0/9] Parallel CPU bringup for x86_64 Paul E. McKenney
2023-02-10 9:02 ` David Woodhouse
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