From: tip-bot for Thomas Gleixner <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: mingo@kernel.org, joro@8bytes.org, hpa@zytor.com,
tglx@linutronix.de, linux-kernel@vger.kernel.org,
jiang.liu@linux.intel.com, bp@alien8.de
Subject: [tip:x86/apic] x86, smpboot: Remove pointless preempt_disable() in native_smp_prepare_cpus()
Date: Fri, 5 Dec 2014 15:25:33 -0800 [thread overview]
Message-ID: <tip-dd60143c04f257bace7c8d805eb1f4aec461b138@git.kernel.org> (raw)
In-Reply-To: <20141205084147.153643952@linutronix.de>
Commit-ID: dd60143c04f257bace7c8d805eb1f4aec461b138
Gitweb: http://git.kernel.org/tip/dd60143c04f257bace7c8d805eb1f4aec461b138
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Fri, 5 Dec 2014 08:48:29 +0000
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sat, 6 Dec 2014 00:19:25 +0100
x86, smpboot: Remove pointless preempt_disable() in native_smp_prepare_cpus()
There is no reason to keep preemption disabled in this function.
We only have two other threads live: kthreadd and idle. Neither of
them is going to preempt. But that preempt_disable forces all the code
inside to do GFP_ATOMIC allocations which is just insane.
Remove it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20141205084147.153643952@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/kernel/smpboot.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 4d2128a..2dc789d 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1084,7 +1084,6 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
{
unsigned int i;
- preempt_disable();
smp_cpu_index_default();
/*
@@ -1102,22 +1101,19 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
}
set_cpu_sibling_map(0);
-
if (smp_sanity_check(max_cpus) < 0) {
pr_info("SMP disabled\n");
disable_smp();
- goto out;
+ return;
}
default_setup_apic_routing();
- preempt_disable();
if (read_apic_id() != boot_cpu_physical_apicid) {
panic("Boot APIC ID in local APIC unexpected (%d vs %d)",
read_apic_id(), boot_cpu_physical_apicid);
/* Or can we switch back to PIC here? */
}
- preempt_enable();
connect_bsp_APIC();
@@ -1151,8 +1147,6 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
uv_system_init();
set_mtrr_aps_delayed_init();
-out:
- preempt_enable();
}
void arch_enable_nonboot_cpus_begin(void)
next prev parent reply other threads:[~2014-12-05 23:26 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-05 8:48 [patch 0/5] x86/iommu: Bootup stage cleanups Thomas Gleixner
2014-12-05 8:48 ` [patch 1/5] x86, smpboot: Remove pointless preempt_disable() in native_smp_prepare_cpus() Thomas Gleixner
2014-12-05 23:25 ` tip-bot for Thomas Gleixner [this message]
2014-12-19 14:02 ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2014-12-05 8:48 ` [patch 2/5] iommu, x86: Restructure setup of the irq remapping feature Thomas Gleixner
2014-12-05 23:25 ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2014-12-05 8:48 ` [patch 3/5] iommu/vt-d: Move iommu preparatory allocations to irq_remap_ops.prepare Thomas Gleixner
2014-12-05 23:26 ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2014-12-11 7:35 ` Yinghai Lu
2014-12-11 14:33 ` Jiang Liu
2014-12-11 17:57 ` Yinghai Lu
2014-12-11 20:30 ` Thomas Gleixner
2014-12-12 2:04 ` Yinghai Lu
2015-04-27 22:46 ` Yinghai Lu
2015-04-29 8:15 ` Jiang Liu
2014-12-05 8:48 ` [patch 4/5] irqdomain: Revert gfp hackery Thomas Gleixner
2014-12-05 23:26 ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2014-12-05 8:48 ` [patch 5/5] iommu/vt-d: Convert allocations to GFP_KERNEL Thomas Gleixner
2014-12-05 23:26 ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2014-12-05 12:22 ` [patch 0/5] x86/iommu: Bootup stage cleanups Joerg Roedel
2015-01-07 7:31 [Patch v2 00/16] Refine IR initialization flow and fixes bugs related to X2APIC Jiang Liu
2015-01-07 7:31 ` [Patch v2 01/16] iommu, x86: Restructure setup of the irq remapping feature Jiang Liu
2015-01-15 12:58 ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2015-01-07 7:31 ` [Patch v2 02/16] iommu/vt-d: Move iommu preparatory allocations to irq_remap_ops.prepare Jiang Liu
2015-01-15 12:58 ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2015-01-07 7:31 ` [Patch v2 03/16] iommu/vt-d: Convert allocations to GFP_KERNEL Jiang Liu
2015-01-15 12:59 ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2015-01-07 7:31 ` [Patch v2 04/16] x86/apic: Panic if kernel doesn't support x2apic but BIOS has enabled x2apic Jiang Liu
2015-01-15 12:59 ` [tip:x86/apic] x86/apic: Panic if kernel doesn' t " tip-bot for Jiang Liu
2015-01-07 7:31 ` [Patch v2 05/16] x86/apic: Kill useless variable x2apic_enabled in function enable_IR_x2apic() Jiang Liu
2015-01-15 12:59 ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07 7:31 ` [Patch v2 06/16] x86/apic: Correctly detect X2APIC status in function enable_IR() Jiang Liu
2015-01-15 13:00 ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07 7:31 ` [Patch v2 07/16] x86/apic: Refine enable_IR_x2apic() and related functions Jiang Liu
2015-01-15 9:24 ` Thomas Gleixner
2015-01-15 13:00 ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-15 13:00 ` [tip:x86/apic] x86/apic: Handle XAPIC remap mode proper tip-bot for Jiang Liu
2015-01-07 7:31 ` [Patch v2 08/16] iommu/vt-d: Prepare for killing function irq_remapping_supported() Jiang Liu
2015-01-15 13:01 ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07 7:31 ` [Patch v2 09/16] iommu/vt-d: Allocate IRQ remapping data structures only for all IOMMUs Jiang Liu
2015-01-15 13:01 ` [tip:x86/apic] " tip-bot for Joerg Roedel
2015-01-07 7:31 ` [Patch v2 10/16] iommu/vt-d: Allow IR works in XAPIC mode though CPU works in X2APIC mode Jiang Liu
2015-01-15 13:01 ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07 7:31 ` [Patch v2 11/16] x86/apic: Only disable CPU x2apic mode when necessary Jiang Liu
2015-01-15 13:02 ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07 7:31 ` [Patch v2 12/16] iommu/amd: Check for irq-remap support amd_iommu_prepare() Jiang Liu
2015-01-15 13:02 ` [tip:x86/apic] " tip-bot for Joerg Roedel
2015-01-07 7:31 ` [Patch v2 13/16] iommu/irq_remapping: Kill function irq_remapping_supported() and related code Jiang Liu
2015-01-15 13:02 ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07 7:31 ` [Patch v2 14/16] iommu/irq_remapping: Refine function irq_remapping_prepare() for maintenance Jiang Liu
2015-01-15 13:03 ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07 7:31 ` [Patch v2 15/16] iommu/irq_remapping: Change variable disable_irq_remap to be static Jiang Liu
2015-01-15 13:03 ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-07 7:31 ` [Patch v2 16/16] iommu/irq_remapping: Normailize the way to detect whether IR is enabled Jiang Liu
2015-01-15 13:03 ` [tip:x86/apic] " tip-bot for Jiang Liu
2015-01-09 12:03 ` [Patch v2 00/16] Refine IR initialization flow and fixes bugs related to X2APIC Joerg Roedel
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