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 --- arch/mips/boot/ecoff.h | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 arch/mips/boot/ecoff.h (limited to 'arch/mips/boot/ecoff.h') diff --git a/arch/mips/boot/ecoff.h b/arch/mips/boot/ecoff.h new file mode 100644 index 000000000..5be79ebfc --- /dev/null +++ b/arch/mips/boot/ecoff.h @@ -0,0 +1,65 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Some ECOFF definitions. + */ + +#include + +typedef struct filehdr { + uint16_t f_magic; /* magic number */ + uint16_t f_nscns; /* number of sections */ + int32_t f_timdat; /* time & date stamp */ + int32_t f_symptr; /* file pointer to symbolic header */ + int32_t f_nsyms; /* sizeof(symbolic hdr) */ + uint16_t f_opthdr; /* sizeof(optional hdr) */ + uint16_t f_flags; /* flags */ +} FILHDR; +#define FILHSZ sizeof(FILHDR) + +#define MIPSEBMAGIC 0x160 +#define MIPSELMAGIC 0x162 + +typedef struct scnhdr { + char s_name[8]; /* section name */ + int32_t s_paddr; /* physical address, aliased s_nlib */ + int32_t s_vaddr; /* virtual address */ + int32_t s_size; /* section size */ + int32_t s_scnptr; /* file ptr to raw data for section */ + int32_t s_relptr; /* file ptr to relocation */ + int32_t s_lnnoptr; /* file ptr to gp histogram */ + uint16_t s_nreloc; /* number of relocation entries */ + uint16_t s_nlnno; /* number of gp histogram entries */ + int32_t s_flags; /* flags */ +} SCNHDR; +#define SCNHSZ sizeof(SCNHDR) +#define SCNROUND ((int32_t)16) + +typedef struct aouthdr { + int16_t magic; /* see above */ + int16_t vstamp; /* version stamp */ + int32_t tsize; /* text size in bytes, padded to DW bdry*/ + int32_t dsize; /* initialized data " " */ + int32_t bsize; /* uninitialized data " " */ + int32_t entry; /* entry pt. */ + int32_t text_start; /* base of text used for this file */ + int32_t data_start; /* base of data used for this file */ + int32_t bss_start; /* base of bss used for this file */ + int32_t gprmask; /* general purpose register mask */ + int32_t cprmask[4]; /* co-processor register masks */ + int32_t gp_value; /* the gp value used for this object */ +} AOUTHDR; +#define AOUTHSZ sizeof(AOUTHDR) + +#define OMAGIC 0407 +#define NMAGIC 0410 +#define ZMAGIC 0413 +#define SMAGIC 0411 +#define LIBMAGIC 0443 + +#define N_TXTOFF(f, a) \ + ((a).magic == ZMAGIC || (a).magic == LIBMAGIC ? 0 : \ + ((a).vstamp < 23 ? \ + ((FILHSZ + AOUTHSZ + (f).f_nscns * SCNHSZ + 7) & 0xfffffff8) : \ + ((FILHSZ + AOUTHSZ + (f).f_nscns * SCNHSZ + SCNROUND-1) & ~(SCNROUND-1)) ) ) +#define N_DATOFF(f, a) \ + N_TXTOFF(f, a) + (a).tsize; -- cgit v1.3.1