From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Waiman Long <longman@redhat.com>,
Will Deacon <will.deacon@arm.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
boqun.feng@gmail.com, linux-arm-kernel@lists.infradead.org,
paulmck@linux.vnet.ibm.com, Ingo Molnar <mingo@kernel.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 28/61] locking/qspinlock/x86: Increase _Q_PENDING_LOOPS upper bound
Date: Thu, 20 Dec 2018 10:18:28 +0100 [thread overview]
Message-ID: <20181220085844.858853635@linuxfoundation.org> (raw)
In-Reply-To: <20181220085843.743900603@linuxfoundation.org>
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
commit b247be3fe89b6aba928bf80f4453d1c4ba8d2063 upstream.
On x86, atomic_cond_read_relaxed will busy-wait with a cpu_relax() loop,
so it is desirable to increase the number of times we spin on the qspinlock
lockword when it is found to be transitioning from pending to locked.
According to Waiman Long:
| Ideally, the spinning times should be at least a few times the typical
| cacheline load time from memory which I think can be down to 100ns or
| so for each cacheline load with the newest systems or up to several
| hundreds ns for older systems.
which in his benchmarking corresponded to 512 iterations.
Suggested-by: Waiman Long <longman@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boqun.feng@gmail.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1524738868-31318-5-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/include/asm/qspinlock.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/include/asm/qspinlock.h b/arch/x86/include/asm/qspinlock.h
index e07cc206919d..8b1ba1607091 100644
--- a/arch/x86/include/asm/qspinlock.h
+++ b/arch/x86/include/asm/qspinlock.h
@@ -5,6 +5,8 @@
#include <asm-generic/qspinlock_types.h>
#include <asm/paravirt.h>
+#define _Q_PENDING_LOOPS (1 << 9)
+
#define queued_spin_unlock queued_spin_unlock
/**
* queued_spin_unlock - release a queued spinlock
--
2.19.1
next prev parent reply other threads:[~2018-12-20 9:18 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-20 9:18 [PATCH 4.9 00/61] 4.9.147-stable review Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 01/61] signal: Introduce COMPAT_SIGMINSTKSZ for use in compat_sys_sigaltstack Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 02/61] lib/interval_tree_test.c: make test options module parameters Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 03/61] lib/interval_tree_test.c: allow full tree search Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 04/61] lib/rbtree_test.c: make input module parameters Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 05/61] lib/rbtree-test: lower default params Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 06/61] lib/interval_tree_test.c: allow users to limit scope of endpoint Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 07/61] timer/debug: Change /proc/timer_list from 0444 to 0400 Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 08/61] pinctrl: sunxi: a83t: Fix IRQ offset typo for PH11 Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 09/61] aio: fix spectre gadget in lookup_ioctx Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 10/61] MMC: OMAP: fix broken MMC on OMAP15XX/OMAP5910/OMAP310 Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 11/61] ARM: mmp/mmp2: fix cpu_is_mmp2() on mmp2-dt Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 12/61] tracing: Fix memory leak in set_trigger_filter() Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 13/61] tracing: Fix memory leak of instance function hash filters Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 14/61] powerpc/msi: Fix NULL pointer access in teardown code Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 15/61] Revert "drm/rockchip: Allow driver to be shutdown on reboot/kexec" Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 16/61] drm/i915/execlists: Apply a full mb before execution for Braswell Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 17/61] mac80211: dont WARN on bad WMM parameters from buggy APs Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 18/61] mac80211: Fix condition validating WMM IE Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 19/61] IB/hfi1: Remove race conditions in user_sdma send path Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 20/61] locking: Remove smp_read_barrier_depends() from queued_spin_lock_slowpath() Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 21/61] locking/qspinlock: Ensure node is initialised before updating prev->next Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 22/61] locking/qspinlock: Bound spinning on pending->locked transition in slowpath Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 23/61] locking/qspinlock: Merge struct __qspinlock into struct qspinlock Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 24/61] locking/qspinlock: Remove unbounded cmpxchg() loop from locking slowpath Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 25/61] locking/qspinlock: Remove duplicate clear_pending() function from PV code Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 26/61] locking/qspinlock: Kill cmpxchg() loop when claiming lock from head of queue Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 27/61] locking/qspinlock: Re-order code Greg Kroah-Hartman
2018-12-20 9:18 ` Greg Kroah-Hartman [this message]
2018-12-20 9:18 ` [PATCH 4.9 29/61] locking/qspinlock, x86: Provide liveness guarantee Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 30/61] locking/qspinlock: Fix build for anonymous union in older GCC compilers Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 31/61] mac80211_hwsim: fix module init error paths for netlink Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 32/61] scsi: libiscsi: Fix NULL pointer dereference in iscsi_eh_session_reset Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 33/61] scsi: vmw_pscsi: Rearrange code to avoid multiple calls to free_irq during unload Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 34/61] x86/earlyprintk/efi: Fix infinite loop on some screen widths Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 35/61] drm/msm: Grab a vblank reference when waiting for commit_done Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 36/61] ARC: io.h: Implement reads{x}()/writes{x}() Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 37/61] bonding: fix 802.3ad state sent to partner when unbinding slave Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 38/61] nfs: dont dirty kernel pages read by direct-io Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 39/61] SUNRPC: Fix a potential race in xprt_connect() Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 40/61] sbus: char: add of_node_put() Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 41/61] drivers/sbus/char: " Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 42/61] drivers/tty: add missing of_node_put() Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 43/61] ide: pmac: add of_node_put() Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 44/61] clk: mvebu: Off by one bugs in cp110_of_clk_get() Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 45/61] clk: mmp: Off by one in mmp_clk_add() Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 46/61] Input: omap-keypad - fix keyboard debounce configuration Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 47/61] libata: whitelist all SAMSUNG MZ7KM* solid-state disks Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 48/61] mv88e6060: disable hardware level MAC learning Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 49/61] net/mlx4_en: Fix build break when CONFIG_INET is off Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 50/61] bpf: check pending signals while verifying programs Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 51/61] ARM: 8814/1: mm: improve/fix ARM v7_dma_inv_range() unaligned address handling Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 52/61] ARM: 8815/1: V7M: align v7m_dma_inv_range() with v7 counterpart Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 53/61] ethernet: fman: fix wrong of_node_put() in probe function Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 54/61] drm/ast: Fix connector leak during driver unload Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 55/61] cifs: In Kconfig CONFIG_CIFS_POSIX needs depends on legacy (insecure cifs) Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 56/61] vhost/vsock: fix reset orphans race with close timeout Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 57/61] i2c: axxia: properly handle master timeout Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 58/61] i2c: scmi: Fix probe error on devices with an empty SMB0001 ACPI device node Greg Kroah-Hartman
2018-12-20 9:18 ` [PATCH 4.9 59/61] nvmet-rdma: fix response use after free Greg Kroah-Hartman
2018-12-20 9:19 ` [PATCH 4.9 60/61] rtc: snvs: add a missing write sync Greg Kroah-Hartman
2018-12-20 9:19 ` [PATCH 4.9 61/61] rtc: snvs: Add timeouts to avoid kernel lockups Greg Kroah-Hartman
2018-12-20 15:00 ` [PATCH 4.9 00/61] 4.9.147-stable review Naresh Kamboju
2018-12-20 18:28 ` Guenter Roeck
2018-12-20 22:55 ` shuah
2018-12-21 9:25 ` Jon Hunter
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