From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Helge Deller <deller@gmx.de>
Subject: [PATCH 4.8 24/37] parisc: Switch to generic sched_clock implementation
Date: Wed, 30 Nov 2016 10:30:01 +0100 [thread overview]
Message-ID: <20161130092730.872712236@linuxfoundation.org> (raw)
In-Reply-To: <20161130092729.623248210@linuxfoundation.org>
4.8-stable review patch. If anyone has any objections, please let me know.
------------------
From: Helge Deller <deller@gmx.de>
commit 43b1f6abd59063a088416a0df042b36450f91f75 upstream.
Drop the open-coded sched_clock() function and replace it by the provided
GENERIC_SCHED_CLOCK implementation. We have seen quite some hung tasks in the
past, which seem to be fixed by this patch.
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/parisc/Kconfig | 4 ++-
arch/parisc/kernel/time.c | 57 ++++++++--------------------------------------
2 files changed, 14 insertions(+), 47 deletions(-)
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -33,7 +33,9 @@ config PARISC
select HAVE_ARCH_HASH
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
- select HAVE_UNSTABLE_SCHED_CLOCK if (SMP || !64BIT)
+ select GENERIC_SCHED_CLOCK
+ select HAVE_UNSTABLE_SCHED_CLOCK if SMP
+ select GENERIC_CLOCKEVENTS
select ARCH_NO_COHERENT_DMA_MMAP
select CPU_NO_EFFICIENT_FFS
--- a/arch/parisc/kernel/time.c
+++ b/arch/parisc/kernel/time.c
@@ -14,6 +14,7 @@
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/sched.h>
+#include <linux/sched_clock.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
@@ -39,18 +40,6 @@
static unsigned long clocktick __read_mostly; /* timer cycles per tick */
-#ifndef CONFIG_64BIT
-/*
- * The processor-internal cycle counter (Control Register 16) is used as time
- * source for the sched_clock() function. This register is 64bit wide on a
- * 64-bit kernel and 32bit on a 32-bit kernel. Since sched_clock() always
- * requires a 64bit counter we emulate on the 32-bit kernel the higher 32bits
- * with a per-cpu variable which we increase every time the counter
- * wraps-around (which happens every ~4 secounds).
- */
-static DEFINE_PER_CPU(unsigned long, cr16_high_32_bits);
-#endif
-
/*
* We keep time on PA-RISC Linux by using the Interval Timer which is
* a pair of registers; one is read-only and one is write-only; both
@@ -121,12 +110,6 @@ irqreturn_t __irq_entry timer_interrupt(
*/
mtctl(next_tick, 16);
-#if !defined(CONFIG_64BIT)
- /* check for overflow on a 32bit kernel (every ~4 seconds). */
- if (unlikely(next_tick < now))
- this_cpu_inc(cr16_high_32_bits);
-#endif
-
/* Skip one clocktick on purpose if we missed next_tick.
* The new CR16 must be "later" than current CR16 otherwise
* itimer would not fire until CR16 wrapped - e.g 4 seconds
@@ -208,7 +191,7 @@ EXPORT_SYMBOL(profile_pc);
/* clock source code */
-static cycle_t read_cr16(struct clocksource *cs)
+static cycle_t notrace read_cr16(struct clocksource *cs)
{
return get_cycles();
}
@@ -287,26 +270,9 @@ void read_persistent_clock(struct timesp
}
-/*
- * sched_clock() framework
- */
-
-static u32 cyc2ns_mul __read_mostly;
-static u32 cyc2ns_shift __read_mostly;
-
-u64 sched_clock(void)
+static u64 notrace read_cr16_sched_clock(void)
{
- u64 now;
-
- /* Get current cycle counter (Control Register 16). */
-#ifdef CONFIG_64BIT
- now = mfctl(16);
-#else
- now = mfctl(16) + (((u64) this_cpu_read(cr16_high_32_bits)) << 32);
-#endif
-
- /* return the value in ns (cycles_2_ns) */
- return mul_u64_u32_shr(now, cyc2ns_mul, cyc2ns_shift);
+ return get_cycles();
}
@@ -316,17 +282,16 @@ u64 sched_clock(void)
void __init time_init(void)
{
- unsigned long current_cr16_khz;
+ unsigned long cr16_hz;
- current_cr16_khz = PAGE0->mem_10msec/10; /* kHz */
clocktick = (100 * PAGE0->mem_10msec) / HZ;
-
- /* calculate mult/shift values for cr16 */
- clocks_calc_mult_shift(&cyc2ns_mul, &cyc2ns_shift, current_cr16_khz,
- NSEC_PER_MSEC, 0);
-
start_cpu_itimer(); /* get CPU 0 started */
+ cr16_hz = 100 * PAGE0->mem_10msec; /* Hz */
+
/* register at clocksource framework */
- clocksource_register_khz(&clocksource_cr16, current_cr16_khz);
+ clocksource_register_hz(&clocksource_cr16, cr16_hz);
+
+ /* register as sched_clock source */
+ sched_clock_register(read_cr16_sched_clock, BITS_PER_LONG, cr16_hz);
}
next prev parent reply other threads:[~2016-11-30 9:31 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20161130093010epcas2p3047cf63814e74dfcc79f43d37b446ae0@epcas2p3.samsung.com>
2016-11-30 9:29 ` [PATCH 4.8 00/37] 4.8.12-stable review Greg Kroah-Hartman
2016-11-30 9:29 ` [PATCH 4.8 07/37] usb: chipidea: move the lock initialization to core file Greg Kroah-Hartman
2016-11-30 9:29 ` [PATCH 4.8 08/37] USB: serial: cp210x: add ID for the Zone DPMX Greg Kroah-Hartman
2016-11-30 9:29 ` [PATCH 4.8 09/37] USB: serial: ftdi_sio: add support for TI CC3200 LaunchPad Greg Kroah-Hartman
2016-11-30 9:29 ` [PATCH 4.8 10/37] Fix USB CB/CBI storage devices with CONFIG_VMAP_STACK=y Greg Kroah-Hartman
2016-11-30 9:29 ` [PATCH 4.8 11/37] scsi: mpt3sas: Fix secure erase premature termination Greg Kroah-Hartman
2016-11-30 16:49 ` Martin K. Petersen
2016-12-01 7:10 ` Greg Kroah-Hartman
2016-11-30 9:29 ` [PATCH 4.8 12/37] tile: avoid using clocksource_cyc2ns with absolute cycle count Greg Kroah-Hartman
2016-11-30 9:29 ` [PATCH 4.8 13/37] cfg80211: limit scan results cache size Greg Kroah-Hartman
2016-11-30 9:29 ` [PATCH 4.8 15/37] drm/radeon: fix power state when port pm is unavailable (v2) Greg Kroah-Hartman
2016-11-30 9:29 ` [PATCH 4.8 16/37] apparmor: fix change_hat not finding hat after policy replacement Greg Kroah-Hartman
2016-11-30 9:29 ` [PATCH 4.8 17/37] NFSv4.x: hide array-bounds warning Greg Kroah-Hartman
2016-11-30 9:29 ` [PATCH 4.8 18/37] x86/fpu: Fix invalid FPU ptrace state after execve() Greg Kroah-Hartman
2016-11-30 9:29 ` [PATCH 4.8 19/37] x86/traps: Ignore high word of regs->cs in early_fixup_exception() Greg Kroah-Hartman
2016-11-30 9:29 ` [PATCH 4.8 20/37] perf/core: Fix address filter parser Greg Kroah-Hartman
2016-11-30 9:29 ` [PATCH 4.8 21/37] perf/x86/intel: Cure bogus unwind from PEBS entries Greg Kroah-Hartman
2016-11-30 9:29 ` [PATCH 4.8 22/37] thermal/powerclamp: add back module device table Greg Kroah-Hartman
2016-11-30 9:30 ` [PATCH 4.8 23/37] parisc: Fix races in parisc_setup_cache_timing() Greg Kroah-Hartman
2016-11-30 9:30 ` Greg Kroah-Hartman [this message]
2016-11-30 9:30 ` [PATCH 4.8 25/37] parisc: Fix race in pci-dma.c Greg Kroah-Hartman
2016-11-30 9:30 ` [PATCH 4.8 26/37] parisc: Also flush data TLB in flush_icache_page_asm Greg Kroah-Hartman
2016-11-30 9:30 ` [PATCH 4.8 27/37] mmc: sdhci-of-esdhc: fixup PRESENT_STATE read Greg Kroah-Hartman
2016-11-30 9:30 ` [PATCH 4.8 28/37] mpi: Fix NULL ptr dereference in mpi_powm() [ver #3] Greg Kroah-Hartman
2016-11-30 9:30 ` [PATCH 4.8 29/37] X.509: Fix double free in x509_cert_parse() " Greg Kroah-Hartman
2016-11-30 9:30 ` [PATCH 4.8 30/37] xc2028: Fix use-after-free bug properly Greg Kroah-Hartman
2016-11-30 9:30 ` [PATCH 4.8 31/37] device-dax: check devm_nsio_enable() return value Greg Kroah-Hartman
2016-11-30 9:30 ` [PATCH 4.8 32/37] device-dax: fail all private mapping attempts Greg Kroah-Hartman
2016-11-30 9:30 ` [PATCH 4.8 33/37] powerpc: Set missing wakeup bit in LPCR on POWER9 Greg Kroah-Hartman
2016-11-30 9:30 ` [PATCH 4.8 34/37] powerpc/mm: Fixup kernel read only mapping Greg Kroah-Hartman
2016-11-30 9:30 ` [PATCH 4.8 35/37] powerpc/boot: Fix the early OPAL console wrappers Greg Kroah-Hartman
2016-11-30 9:30 ` [PATCH 4.8 36/37] can: bcm: fix support for CAN FD frames Greg Kroah-Hartman
2016-11-30 9:30 ` [PATCH 4.8 37/37] mm, oom: stop pre-mature high-order OOM killer invocations Greg Kroah-Hartman
[not found] ` <20161130092730.460938123@linuxfoundation.org>
2016-11-30 10:51 ` [PATCH 4.8 14/37] drm/amdgpu: fix power state when port pm is unavailable Peter Wu
2016-11-30 11:53 ` Greg Kroah-Hartman
2016-12-05 0:11 ` Peter Wu
2016-12-05 14:46 ` Greg Kroah-Hartman
2016-11-30 16:04 ` [PATCH 4.8 00/37] 4.8.12-stable review Shuah Khan
2016-12-01 7:14 ` Greg Kroah-Hartman
2016-11-30 23:34 ` Guenter Roeck
2016-12-01 7:15 ` Greg Kroah-Hartman
[not found] ` <583ed167.6602c20a.c3129.a6b8@mx.google.com>
[not found] ` <m2oa0wkjlk.fsf@baylibre.com>
2016-12-01 7:11 ` Greg Kroah-Hartman
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