From 0d6526f82c3cdefcca47f73f5fc08dc6f335eac6 Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Mon, 21 Sep 2026 17:37:22 -0700 Subject: sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling bug 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 Suggested-by: Chen Yu Signed-off-by: Tim Chen Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Kayra Cizmeci Cc: # v7.2.x Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com --- rust/zerocopy/rustdoc/style.css | 56 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 rust/zerocopy/rustdoc/style.css (limited to 'rust/zerocopy/rustdoc/style.css') diff --git a/rust/zerocopy/rustdoc/style.css b/rust/zerocopy/rustdoc/style.css new file mode 100644 index 000000000..d2d55ad2e --- /dev/null +++ b/rust/zerocopy/rustdoc/style.css @@ -0,0 +1,56 @@ +/* SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT */ +/* +Copyright 2026 The Fuchsia Authors + +Licensed under a BSD-style license , Apache License, Version 2.0 +, or the MIT +license , at your option. +This file may not be copied, modified, or distributed except according to +those terms. +*/ + +.codegen-tabs { + display: grid; + grid-template-columns: repeat(var(--arity), minmax(200px, 1fr)); + grid-template-rows: auto 1fr; + column-gap: 1rem; +} + +.codegen-tabs:not(:has(> details[open]))::after { + grid-column: 1/-1; + content: 'Click one of the above headers to expand its contents.'; + font-style: italic; + font-size: small; + text-align: center; +} + +.codegen-tabs details { + display: grid; + grid-column: 1 / -1; + grid-row: 1 / span 2; + grid-template-columns: subgrid; + grid-template-rows: subgrid; +} + +.codegen-tabs summary { + display: grid; + grid-column: var(--n) / span 1; + grid-row: 1; + z-index: 1; + border-bottom: 2px solid var(--headings-border-bottom-color); + cursor: pointer; +} + +.codegen-tabs details[open] > summary { + background-color: var(--code-block-background-color); + border-bottom-color: var(--target-border-color); +} + +.codegen-tabs details::details-content { + grid-column: 1 / -1; + grid-row: 2; +} + +.codegen-tabs details:not([open])::details-content { + display: none; +} -- cgit v1.3.1