From: Ben Hutchings <ben@decadent.org.uk>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: akpm@linux-foundation.org, Denis Kirjanov <kda@linux-powerpc.org>
Subject: [PATCH 3.16 58/63] Revert "sched/fair: Fix bandwidth timer clock drift condition"
Date: Wed, 08 Jan 2020 19:43:56 +0000 [thread overview]
Message-ID: <lsq.1578512578.981696343@decadent.org.uk> (raw)
In-Reply-To: <lsq.1578512578.117275639@decadent.org.uk>
3.16.81-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Ben Hutchings <ben@decadent.org.uk>
This reverts commit eb29ee5a3873134917a760bf9c416da0a089a0be, which
was commit 512ac999d2755d2b7109e996a76b6fb8b888631d upstream. This
introduced a regression and doesn't seem to have been suitable for
older stable branches. (It has been fixed differently upstream.)
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3163,7 +3163,6 @@ void __refill_cfs_bandwidth_runtime(stru
now = sched_clock_cpu(smp_processor_id());
cfs_b->runtime = cfs_b->quota;
cfs_b->runtime_expires = now + ktime_to_ns(cfs_b->period);
- cfs_b->expires_seq++;
}
static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
@@ -3186,7 +3185,6 @@ static int assign_cfs_rq_runtime(struct
struct task_group *tg = cfs_rq->tg;
struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(tg);
u64 amount = 0, min_amount, expires;
- int expires_seq;
/* note: this is a positive sum as runtime_remaining <= 0 */
min_amount = sched_cfs_bandwidth_slice() - cfs_rq->runtime_remaining;
@@ -3212,7 +3210,6 @@ static int assign_cfs_rq_runtime(struct
cfs_b->idle = 0;
}
}
- expires_seq = cfs_b->expires_seq;
expires = cfs_b->runtime_expires;
raw_spin_unlock(&cfs_b->lock);
@@ -3222,10 +3219,8 @@ static int assign_cfs_rq_runtime(struct
* spread between our sched_clock and the one on which runtime was
* issued.
*/
- if (cfs_rq->expires_seq != expires_seq) {
- cfs_rq->expires_seq = expires_seq;
+ if ((s64)(expires - cfs_rq->runtime_expires) > 0)
cfs_rq->runtime_expires = expires;
- }
return cfs_rq->runtime_remaining > 0;
}
@@ -3251,9 +3246,12 @@ static void expire_cfs_rq_runtime(struct
* has not truly expired.
*
* Fortunately we can check determine whether this the case by checking
- * whether the global deadline(cfs_b->expires_seq) has advanced.
+ * whether the global deadline has advanced. It is valid to compare
+ * cfs_b->runtime_expires without any locks since we only care about
+ * exact equality, so a partial write will still work.
*/
- if (cfs_rq->expires_seq == cfs_b->expires_seq) {
+
+ if (cfs_rq->runtime_expires != cfs_b->runtime_expires) {
/* extend local deadline, drift is bounded above by 2 ticks */
cfs_rq->runtime_expires += TICK_NSEC;
} else {
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -187,7 +187,6 @@ struct cfs_bandwidth {
u64 quota, runtime;
s64 hierarchal_quota;
u64 runtime_expires;
- int expires_seq;
int idle, timer_active;
struct hrtimer period_timer, slack_timer;
@@ -377,7 +376,6 @@ struct cfs_rq {
#ifdef CONFIG_CFS_BANDWIDTH
int runtime_enabled;
- int expires_seq;
u64 runtime_expires;
s64 runtime_remaining;
next prev parent reply other threads:[~2020-01-08 19:48 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-08 19:42 [PATCH 3.16 00/63] 3.16.81-rc1 review Ben Hutchings
2020-01-08 19:42 ` [PATCH 3.16 01/63] net: qlogic: Fix memory leak in ql_alloc_large_buffers Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 02/63] net: qlogic: Fix error paths in ql_alloc_large_buffers() Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 03/63] HID: sony: Update device ids Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 04/63] HID: sony: Support DS4 dongle Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 05/63] crypto: cts - fix crash on short inputs Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 06/63] tracing/uprobes: Fix output for multiple string arguments Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 07/63] libceph: handle an empty authorize reply Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 08/63] ALSA: compress: add support for 32bit calls in a 64bit kernel Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 09/63] mmc: debugfs: Add a restriction to mmc debugfs clock setting Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 10/63] mmc: sanitize 'bus width' in debug output Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 11/63] mmc: core: shut up "voltage-ranges unspecified" pr_info() Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 12/63] usb: dwc3: gadget: Fix suspend/resume during device mode Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 13/63] arm64: mm: Add trace_irqflags annotations to do_debug_exception() Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 14/63] mmc: core: fix using wrong io voltage if mmc_select_hs200 fails Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 15/63] mm/rmap: replace BUG_ON(anon_vma->degree) with VM_WARN_ON Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 16/63] kbuild: setlocalversion: print error to STDERR Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 17/63] usb: gadget: composite: fix dereference after null check coverify warning Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 18/63] usb: gadget: serial: fix re-ordering of tx data Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 19/63] usb: gadget: Add the gserial port checking in gs_start_tx() Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 20/63] tcp/dccp: drop SYN packets if accept queue is full Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 21/63] arm64: traps: disable irq in die() Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 22/63] usb: renesas_usbhs: gadget: fix unused-but-set-variable warning Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 23/63] xhci: Fix port resume done detection for SS ports with LPM enabled Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 24/63] mmc: block: Allow more than 8 partitions per card Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 25/63] arm64: fix COMPAT_SHMLBA definition for large pages Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 26/63] ARM: 8458/1: bL_switcher: add GIC dependency Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 27/63] net: diag: support v4mapped sockets in inet_diag_find_one_icsk() Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 28/63] asm-generic: Fix local variable shadow in __set_fixmap_offset Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 29/63] staging: ashmem: Avoid deadlock with mmap/shrink Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 30/63] staging: ashmem: Add missing include Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 31/63] staging: ion: Set minimum carveout heap allocation order to PAGE_SHIFT Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 32/63] staging: goldfish: audio: fix compiliation on arm Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 33/63] ARM: 8510/1: rework ARM_CPU_SUSPEND dependencies Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 34/63] arm64/kernel: fix incorrect EL0 check in inv_entry macro Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 35/63] arm64: kernel: Include _AC definition in page.h Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 36/63] suspend: simplify block I/O handling Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 37/63] PM / Hibernate: Call flush_icache_range() on pages restored in-place Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 38/63] usb: gadget: configfs: add mutex lock before unregister gadget Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 39/63] usb: gadget: rndis: free response queue during REMOTE_NDIS_RESET_MSG Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 40/63] video: fbdev: Set pixclock = 0 in goldfishfb Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 41/63] arm64: kconfig: drop CONFIG_RTC_LIB dependency Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 42/63] mmc: mmc: fix switch timeout issue caused by jiffies precision Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 43/63] cfg80211: size various nl80211 messages correctly Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 44/63] arm64: support keyctl() system call in 32-bit mode Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 45/63] stmmac: copy unicast mac address to MAC registers Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 46/63] arm64: debug: Don't propagate UNKNOWN FAR into si_code for debug signals Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 47/63] arm64: debug: Ensure debug handlers check triggering exception level Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 48/63] x86/atomic: Fix smp_mb__{before,after}_atomic() Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 49/63] locking,x86: Kill atomic_or_long() Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 50/63] locking/x86: Remove the unused atomic_inc_short() methd Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 51/63] dmaengine: qcom: bam_dma: Fix resource leak Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 52/63] mwifiex: Fix NL80211_TX_POWER_LIMITED Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 53/63] xhci: fix USB3 device initiated resume race with roothub autosuspend Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 54/63] Make filldir[64]() verify the directory entry filename is valid Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 55/63] filldir[64]: remove WARN_ON_ONCE() for bad directory entries Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 56/63] ext4: Introduce ext4_clamp_want_extra_isize() Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 57/63] ext4: add more paranoia checking in ext4_expand_extra_isize handling Ben Hutchings
2020-01-08 19:43 ` Ben Hutchings [this message]
2020-01-08 19:43 ` [PATCH 3.16 59/63] can: kvaser_usb: kvaser_usb_leaf: Fix some info-leaks to USB devices Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 60/63] media: cpia2: Fix use-after-free in cpia2_exit Ben Hutchings
2020-01-08 19:43 ` [PATCH 3.16 61/63] mwifiex: don't follow AP if country code received from EEPROM Ben Hutchings
2020-01-08 19:44 ` [PATCH 3.16 62/63] mwifiex: fix possible heap overflow in mwifiex_process_country_ie() Ben Hutchings
2020-01-09 12:12 ` Salvatore Bonaccorso
2020-01-10 16:01 ` Ben Hutchings
2020-01-08 19:44 ` [PATCH 3.16 63/63] scsi: libsas: stop discovering if oob mode is disconnected Ben Hutchings
2020-01-08 22:52 ` [PATCH 3.16 00/63] 3.16.81-rc1 review Guenter Roeck
2020-01-09 1:14 ` Ben Hutchings
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