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 --- mm/Makefile | 150 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 150 insertions(+) create mode 100644 mm/Makefile (limited to 'mm/Makefile') diff --git a/mm/Makefile b/mm/Makefile new file mode 100644 index 000000000..e7245cb88 --- /dev/null +++ b/mm/Makefile @@ -0,0 +1,150 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for the linux memory manager. +# + +KASAN_SANITIZE_slab_common.o := n +KASAN_SANITIZE_slub.o := n +KASAN_SANITIZE_kmemleak.o := n +KCSAN_SANITIZE_kmemleak.o := n + +# These produce frequent data race reports: most of them are due to races on +# the same word but accesses to different bits of that word. Re-enable KCSAN +# for these when we have more consensus on what to do about them. +KCSAN_SANITIZE_slab_common.o := n +KCSAN_SANITIZE_slub.o := n +KCSAN_SANITIZE_page_alloc.o := n +# But enable explicit instrumentation for memory barriers. +KCSAN_INSTRUMENT_BARRIERS := y + +# These files are disabled because they produce non-interesting and/or +# flaky coverage that is not a function of syscall inputs. E.g. slab is out of +# free pages, or a task is migrated between nodes. +KCOV_INSTRUMENT_slab_common.o := n +KCOV_INSTRUMENT_slub.o := n +KCOV_INSTRUMENT_page_alloc.o := n +KCOV_INSTRUMENT_debug-pagealloc.o := n +KCOV_INSTRUMENT_kmemleak.o := n +KCOV_INSTRUMENT_memcontrol.o := n +KCOV_INSTRUMENT_memcontrol-v1.o := n +KCOV_INSTRUMENT_mmzone.o := n +KCOV_INSTRUMENT_vmstat.o := n +KCOV_INSTRUMENT_failslab.o := n + +CFLAGS_init-mm.o += -Wno-override-init + +mmu-y := nommu.o +mmu-$(CONFIG_MMU) := highmem.o memory.o mincore.o \ + mlock.o mmap.o mmu_gather.o mprotect.o mremap.o \ + msync.o page_vma_mapped.o pagewalk.o \ + pgtable-generic.o rmap.o vmalloc.o vma.o vma_exec.o + + +ifdef CONFIG_CROSS_MEMORY_ATTACH +mmu-$(CONFIG_MMU) += process_vm_access.o +endif + +ifdef CONFIG_64BIT +mmu-$(CONFIG_MMU) += mseal.o +endif + +obj-y := filemap.o mempool.o oom_kill.o fadvise.o \ + maccess.o page-writeback.o folio-compat.o \ + readahead.o folio.o truncate.o vmscan.o shrinker.o \ + shmem.o util.o mmzone.o vmstat.o backing-dev.o \ + mm_init.o percpu.o slab_common.o \ + compaction.o show_mem.o \ + interval_tree.o list_lru.o workingset.o \ + debug.o gup.o mmap_lock.o vma_init.o $(mmu-y) + +# Give 'page_alloc' its own module-parameter namespace +page-alloc-y := page_alloc.o +page-alloc-$(CONFIG_SHUFFLE_PAGE_ALLOCATOR) += shuffle.o + +# Give 'memory_hotplug' its own module-parameter namespace +memory-hotplug-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o + +obj-y += page-alloc.o +obj-y += page_frag_cache.o +obj-y += init-mm.o +obj-y += memblock.o +obj-y += $(memory-hotplug-y) +obj-y += slub.o + +ifdef CONFIG_MMU + obj-$(CONFIG_ADVISE_SYSCALLS) += madvise.o +endif + +obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o +obj-$(CONFIG_ZSWAP) += zswap.o +obj-$(CONFIG_HAS_DMA) += dmapool.o +obj-$(CONFIG_HUGETLBFS) += hugetlb.o hugetlb_sysfs.o hugetlb_sysctl.o +ifdef CONFIG_CMA +obj-$(CONFIG_HUGETLBFS) += hugetlb_cma.o +endif +obj-$(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP) += hugetlb_vmemmap.o +obj-$(CONFIG_NUMA) += mempolicy.o +obj-$(CONFIG_SPARSEMEM) += sparse.o +obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o +obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o +obj-$(CONFIG_KSM) += ksm.o +obj-$(CONFIG_PAGE_POISONING) += page_poison.o +obj-$(CONFIG_KASAN) += kasan/ +obj-$(CONFIG_KFENCE) += kfence/ +obj-$(CONFIG_KMSAN) += kmsan/ +obj-$(CONFIG_FAILSLAB) += failslab.o +obj-$(CONFIG_FAIL_PAGE_ALLOC) += fail_page_alloc.o +obj-$(CONFIG_MEMTEST) += memtest.o +obj-$(CONFIG_MIGRATION) += migrate.o +obj-$(CONFIG_NUMA) += memory-tiers.o +obj-$(CONFIG_DEVICE_MIGRATION) += migrate_device.o +obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o +obj-$(CONFIG_PAGE_COUNTER) += page_counter.o +obj-$(CONFIG_LIVEUPDATE_MEMFD) += memfd_luo.o +obj-$(CONFIG_MEMCG_V1) += memcontrol-v1.o +obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o +ifdef CONFIG_BPF_SYSCALL +obj-$(CONFIG_MEMCG) += bpf_memcontrol.o +endif +obj-$(CONFIG_CGROUP_HUGETLB) += hugetlb_cgroup.o +obj-$(CONFIG_GUP_TEST) += gup_test.o +obj-$(CONFIG_DMAPOOL_TEST) += dmapool_test.o +obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o +obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o +obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o +obj-$(CONFIG_DEBUG_RODATA_TEST) += rodata_test.o +obj-$(CONFIG_DEBUG_VM_PGTABLE) += debug_vm_pgtable.o +obj-$(CONFIG_PAGE_OWNER) += page_owner.o +obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o +obj-$(CONFIG_ZSMALLOC) += zsmalloc.o +obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o +obj-$(CONFIG_CMA) += cma.o +obj-$(CONFIG_NUMA) += numa.o +obj-$(CONFIG_NUMA_MEMBLKS) += numa_memblks.o +obj-$(CONFIG_NUMA_EMU) += numa_emulation.o +obj-$(CONFIG_GENERIC_ARCH_NUMA) += arch_numa.o +obj-$(CONFIG_BALLOON) += balloon.o +obj-$(CONFIG_PAGE_EXTENSION) += page_ext.o +obj-$(CONFIG_PAGE_TABLE_CHECK) += page_table_check.o +obj-$(CONFIG_CMA_DEBUGFS) += cma_debug.o +obj-$(CONFIG_SECRETMEM) += secretmem.o +obj-$(CONFIG_CMA_SYSFS) += cma_sysfs.o +obj-$(CONFIG_USERFAULTFD) += userfaultfd.o +obj-$(CONFIG_IDLE_PAGE_TRACKING) += page_idle.o +obj-$(CONFIG_DEBUG_PAGEALLOC) += debug_page_alloc.o +obj-$(CONFIG_DEBUG_PAGE_REF) += debug_page_ref.o +obj-$(CONFIG_DAMON) += damon/ +obj-$(CONFIG_HARDENED_USERCOPY) += usercopy.o +obj-$(CONFIG_PERCPU_STATS) += percpu-stats.o +obj-$(CONFIG_ZONE_DEVICE) += memremap.o +obj-$(CONFIG_HMM_MIRROR) += hmm.o +obj-$(CONFIG_MEMFD_CREATE) += memfd.o +obj-$(CONFIG_MAPPING_DIRTY_HELPERS) += mapping_dirty_helpers.o +obj-$(CONFIG_PTDUMP) += ptdump.o +obj-$(CONFIG_PAGE_REPORTING) += page_reporting.o +obj-$(CONFIG_GENERIC_IOREMAP) += ioremap.o +obj-$(CONFIG_SHRINKER_DEBUG) += shrinker_debug.o +obj-$(CONFIG_EXECMEM) += execmem.o +obj-$(CONFIG_TMPFS_QUOTA) += shmem_quota.o +obj-$(CONFIG_LAZY_MMU_MODE_KUNIT_TEST) += tests/lazy_mmu_mode_kunit.o +obj-$(CONFIG_MEM_ALLOC_PROFILING) += alloc_tag.o -- cgit v1.3.1