From: Daniel J Blueman <daniel@numascale.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Bjorn Helgaas <bhelgaas@google.com>
Cc: Daniel J Blueman <daniel@numascale.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, Steffen Persvold <sp@numascale.com>
Subject: [PATCH v3 2/5] Numachip: Elide self-IPI ICR polling
Date: Sun, 2 Nov 2014 16:10:10 +0800 [thread overview]
Message-ID: <1414915813-2462-2-git-send-email-daniel@numascale.com> (raw)
In-Reply-To: <1414915813-2462-1-git-send-email-daniel@numascale.com>
The default self-IPI path polls the ICR to delay sending the IPI until
there is no IPI in progress. This is redundant on x86-86 APICs, since
IPIs are queued. See the AMD64 Architecture Programmer's Manual, vol 2,
p525.
Signed-off-by: Daniel J Blueman <daniel@numascale.com>
---
arch/x86/kernel/apic/apic_numachip.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/apic/apic_numachip.c b/arch/x86/kernel/apic/apic_numachip.c
index 81d70ba..bd083c0 100644
--- a/arch/x86/kernel/apic/apic_numachip.c
+++ b/arch/x86/kernel/apic/apic_numachip.c
@@ -145,7 +145,7 @@ static void numachip_send_IPI_all(int vector)
static void numachip_send_IPI_self(int vector)
{
- __default_send_IPI_shortcut(APIC_DEST_SELF, vector, APIC_DEST_PHYSICAL);
+ apic_write(APIC_SELF_IPI, vector);
}
static int __init numachip_probe(void)
--
1.9.1
next prev parent reply other threads:[~2014-11-02 8:10 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-02 8:10 [PATCH v3 1/5] Numachip: Fix 16-bit APIC ID truncation Daniel J Blueman
2014-11-02 8:10 ` Daniel J Blueman [this message]
2014-11-02 8:10 ` [PATCH v3 3/5] Numachip: Add safe is-present function Daniel J Blueman
2014-11-03 19:45 ` Thomas Gleixner
2014-11-03 22:55 ` Daniel J Blueman
2014-11-03 22:58 ` Thomas Gleixner
2014-11-02 8:10 ` [PATCH v3 4/5] Numachip: APIC driver cleanups Daniel J Blueman
2014-11-02 8:10 ` [PATCH v3 5/5] Use 2GB memory block size on large x86-64 systems Daniel J Blueman
2014-11-03 19:38 ` Thomas Gleixner
2014-11-03 23:15 ` Daniel J Blueman
2014-11-03 23:36 ` Thomas Gleixner
2014-11-04 7:30 ` Daniel J Blueman
2014-11-04 7:50 ` Thomas Gleixner
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