diff options
| author | Tim Chen <tim.c.chen@linux.intel.com> | 2026-09-21 17:37:22 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2026-09-22 10:49:53 +0200 |
| commit | 0d6526f82c3cdefcca47f73f5fc08dc6f335eac6 (patch) | |
| tree | 176dc2d685debcfb082c151ee94f2425ac96b364 /arch/mips/Kbuild.platforms | |
| download | linux-stable-0d6526f82c3cdefcca47f73f5fc08dc6f335eac6.tar.gz linux-stable-0d6526f82c3cdefcca47f73f5fc08dc6f335eac6.zip | |
sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling buggrafted
alb_break_llc() decides whether to break LLC preference during active
load balance. It does so by testing that every runnable fair task on the
source rq prefers its LLC:
env->src_rq->nr_pref_llc_running == env->src_rq->cfs.h_nr_runnable
But the two counters cover different sets. nr_pref_llc_running is updated
in account_llc_enqueue()/account_llc_dequeue(), next to cfs_rq->nr_queued,
so it follows queued tasks. h_nr_runnable is updated in set_delayed()/
clear_delayed() and drops delay-dequeued tasks.
So under DELAY_DEQUEUE, a preferring task that goes to sleep stays counted
in nr_pref_llc_running while h_nr_runnable falls. The equality then breaks,
alb_break_llc() returns false, and active balance is free to pull a task
off its preferred LLC. Active balance only moves runnable tasks, and this
is the only LLC check it consults: once the stopper runs, LBF_ACTIVE_LB
skips the per-task test in can_migrate_task(). The runnable set is the one
we want.
Fix it on the counter side. A task should be counted in
nr_pref_llc_running exactly while it is both queued on its preferred LLC
(pref_llc_queued) and runnable (!sched_delayed). Define that membership
once in task_pref_llc_runnable(), and adjust the counter only through
pref_llc_running_inc()/pref_llc_running_dec() from the four sites that
change either input: account_llc_enqueue(), account_llc_dequeue(),
set_delayed() and clear_delayed(). Gating every update on the same
predicate keeps the delay, wake and dequeue paths from double-counting
or underflowing; see the comments at those sites for the ordering.
nr_llc_running and sd->llc_counts are not touched and stay on queued
semantics.
Fixes: 714059f79ff0 ("sched/cache: Handle moving single tasks to/from their preferred LLC")
Closes: https://lore.kernel.org/lkml/20260827135000.735138-1-zhanxusheng@xiaomi.com/
Reported-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Suggested-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kayra Cizmeci <kayracizmeci@gmail.com>
Cc: <stable@kernel.org> # v7.2.x
Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com
Diffstat (limited to 'arch/mips/Kbuild.platforms')
| -rw-r--r-- | arch/mips/Kbuild.platforms | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/arch/mips/Kbuild.platforms b/arch/mips/Kbuild.platforms new file mode 100644 index 000000000..41a00fa86 --- /dev/null +++ b/arch/mips/Kbuild.platforms @@ -0,0 +1,38 @@ +# SPDX-License-Identifier: GPL-2.0 +# All platforms listed in alphabetic order + +platform-$(CONFIG_MIPS_ALCHEMY) += alchemy/ +platform-$(CONFIG_ATH25) += ath25/ +platform-$(CONFIG_ATH79) += ath79/ +platform-$(CONFIG_BCM47XX) += bcm47xx/ +platform-$(CONFIG_BCM63XX) += bcm63xx/ +platform-$(CONFIG_BMIPS_GENERIC) += bmips/ +platform-$(CONFIG_CAVIUM_OCTEON_SOC) += cavium-octeon/ +platform-$(CONFIG_EYEQ) += mobileye/ +platform-$(CONFIG_MIPS_COBALT) += cobalt/ +platform-$(CONFIG_MACH_DECSTATION) += dec/ +platform-$(CONFIG_ECONET) += econet/ +platform-$(CONFIG_MIPS_GENERIC) += generic/ +platform-$(CONFIG_MACH_JAZZ) += jazz/ +platform-$(CONFIG_LANTIQ) += lantiq/ +platform-$(CONFIG_MACH_LOONGSON2EF) += loongson2ef/ +platform-$(CONFIG_MACH_LOONGSON32) += loongson32/ +platform-$(CONFIG_MACH_LOONGSON64) += loongson64/ +platform-$(CONFIG_MIPS_MALTA) += mti-malta/ +platform-$(CONFIG_MACH_NINTENDO64) += n64/ +platform-$(CONFIG_PIC32MZDA) += pic32/ +platform-$(CONFIG_RALINK) += ralink/ +platform-$(CONFIG_MIKROTIK_RB532) += rb532/ +platform-$(CONFIG_SGI_IP22) += sgi-ip22/ +platform-$(CONFIG_SGI_IP27) += sgi-ip27/ +platform-$(CONFIG_SGI_IP28) += sgi-ip22/ +platform-$(CONFIG_SGI_IP30) += sgi-ip30/ +platform-$(CONFIG_SGI_IP32) += sgi-ip32/ +platform-$(CONFIG_SIBYTE_BCM112X) += sibyte/ +platform-$(CONFIG_SIBYTE_SB1250) += sibyte/ +platform-$(CONFIG_SIBYTE_BCM1x80) += sibyte/ +platform-$(CONFIG_SNI_RM) += sni/ +platform-$(CONFIG_MACH_TX49XX) += txx9/ + +# include the platform specific files +include $(patsubst %/, $(srctree)/arch/mips/%/Platform, $(platform-y)) |