From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "Ahmed S. Darwish" <a.darwish@linutronix.de>,
Thomas Gleixner <tglx@linutronix.de>,
Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 5.4 17/46] time/sched_clock: Expire timer in hardirq context
Date: Thu, 9 Apr 2020 23:48:40 -0400 [thread overview]
Message-ID: <20200410034909.8922-17-sashal@kernel.org> (raw)
In-Reply-To: <20200410034909.8922-1-sashal@kernel.org>
From: "Ahmed S. Darwish" <a.darwish@linutronix.de>
[ Upstream commit 2c8bd58812ee3dbf0d78b566822f7eacd34bdd7b ]
To minimize latency, PREEMPT_RT kernels expires hrtimers in preemptible
softirq context by default. This can be overriden by marking the timer's
expiry with HRTIMER_MODE_HARD.
sched_clock_timer is missing this annotation: if its callback is preempted
and the duration of the preemption exceeds the wrap around time of the
underlying clocksource, sched clock will get out of sync.
Mark the sched_clock_timer for expiry in hard interrupt context.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200309181529.26558-1-a.darwish@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/time/sched_clock.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
index dbd69052eaa66..a5538dd76a819 100644
--- a/kernel/time/sched_clock.c
+++ b/kernel/time/sched_clock.c
@@ -207,7 +207,8 @@ sched_clock_register(u64 (*read)(void), int bits, unsigned long rate)
if (sched_clock_timer.function != NULL) {
/* update timeout for clock wrap */
- hrtimer_start(&sched_clock_timer, cd.wrap_kt, HRTIMER_MODE_REL);
+ hrtimer_start(&sched_clock_timer, cd.wrap_kt,
+ HRTIMER_MODE_REL_HARD);
}
r = rate;
@@ -251,9 +252,9 @@ void __init generic_sched_clock_init(void)
* Start the timer to keep sched_clock() properly updated and
* sets the initial epoch.
*/
- hrtimer_init(&sched_clock_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ hrtimer_init(&sched_clock_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
sched_clock_timer.function = sched_clock_poll;
- hrtimer_start(&sched_clock_timer, cd.wrap_kt, HRTIMER_MODE_REL);
+ hrtimer_start(&sched_clock_timer, cd.wrap_kt, HRTIMER_MODE_REL_HARD);
}
/*
@@ -290,7 +291,7 @@ void sched_clock_resume(void)
struct clock_read_data *rd = &cd.read_data[0];
rd->epoch_cyc = cd.actual_read_sched_clock();
- hrtimer_start(&sched_clock_timer, cd.wrap_kt, HRTIMER_MODE_REL);
+ hrtimer_start(&sched_clock_timer, cd.wrap_kt, HRTIMER_MODE_REL_HARD);
rd->read_sched_clock = cd.actual_read_sched_clock;
}
--
2.20.1
next prev parent reply other threads:[~2020-04-10 3:56 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-10 3:48 [PATCH AUTOSEL 5.4 01/46] cpufreq: imx6q: Fixes unwanted cpu overclocking on i.MX6ULL Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 02/46] staging: wilc1000: avoid double unlocking of 'wilc->hif_cs' mutex Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 03/46] media: venus: hfi_parser: Ignore HEVC encoding for V1 Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 04/46] firmware: arm_sdei: fix double-lock on hibernate with shared events Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 05/46] null_blk: Fix the null_add_dev() error path Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 06/46] null_blk: Handle null_add_dev() failures properly Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 07/46] null_blk: fix spurious IO errors after failed past-wp access Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 08/46] media: imx: imx7_mipi_csis: Power off the source when stopping streaming Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 09/46] media: imx: imx7-media-csi: Fix video field handling Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 10/46] xhci: bail out early if driver can't accress host in resume Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 11/46] ACPI: EC: Do not clear boot_ec_is_ecdt in acpi_ec_add() Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 12/46] x86: Don't let pgprot_modify() change the page encryption bit Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 13/46] dma-mapping: Fix dma_pgprot() for unencrypted coherent pages Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 14/46] block: keep bdi->io_pages in sync with max_sectors_kb for stacked devices Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 15/46] debugfs: Check module state before warning in {full/open}_proxy_open() Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 16/46] irqchip/versatile-fpga: Handle chained IRQs properly Sasha Levin
2020-04-10 3:48 ` Sasha Levin [this message]
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 18/46] media: allegro: fix type of gop_length in channel_create message Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 19/46] sched: Avoid scale real weight down to zero Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 20/46] selftests/x86/ptrace_syscall_32: Fix no-vDSO segfault Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 21/46] PCI/switchtec: Fix init_completion race condition with poll_wait() Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 22/46] block, bfq: move forward the getting of an extra ref in bfq_bfqq_move Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 23/46] media: i2c: video-i2c: fix build errors due to 'imply hwmon' Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 24/46] libata: Remove extra scsi_host_put() in ata_scsi_add_hosts() Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 25/46] pstore/platform: fix potential mem leak if pstore_init_fs failed Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 26/46] gfs2: Do log_flush in gfs2_ail_empty_gl even if ail list is empty Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 27/46] gfs2: Don't demote a glock until its revokes are written Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 28/46] cpufreq: imx6q: fix error handling Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 29/46] x86/boot: Use unsigned comparison for addresses Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 30/46] efi/x86: Ignore the memory attributes table on i386 Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 31/46] genirq/irqdomain: Check pointer in irq_domain_alloc_irqs_hierarchy() Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 32/46] blk-mq: Keep set->nr_hw_queues and set->map[].nr_queues in sync Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 33/46] block: Fix use-after-free issue accessing struct io_cq Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 34/46] media: i2c: ov5695: Fix power on and off sequences Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 35/46] usb: dwc3: core: add support for disabling SS instances in park mode Sasha Levin
2020-04-10 3:48 ` [PATCH AUTOSEL 5.4 36/46] irqchip/gic-v4: Provide irq_retrigger to avoid circular locking dependency Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 37/46] md: check arrays is suspended in mddev_detach before call quiesce operations Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 38/46] firmware: fix a double abort case with fw_load_sysfs_fallback Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 39/46] spi: spi-fsl-dspi: Replace interruptible wait queue with a simple completion Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 40/46] locking/lockdep: Avoid recursion in lockdep_count_{for,back}ward_deps() Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 41/46] block, bfq: fix use-after-free in bfq_idle_slice_timer_body Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 42/46] btrfs: hold a ref on the root in btrfs_recover_relocation Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 43/46] btrfs: qgroup: ensure qgroup_rescan_running is only set when the worker is at least queued Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 44/46] btrfs: remove a BUG_ON() from merge_reloc_roots() Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 45/46] btrfs: restart relocate_tree_blocks properly Sasha Levin
2020-04-10 3:49 ` [PATCH AUTOSEL 5.4 46/46] btrfs: track reloc roots based on their commit root bytenr Sasha Levin
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