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/alpha/boot/misc.c | 172 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 172 insertions(+) create mode 100644 arch/alpha/boot/misc.c (limited to 'arch/alpha/boot/misc.c') diff --git a/arch/alpha/boot/misc.c b/arch/alpha/boot/misc.c new file mode 100644 index 000000000..1ab91852d --- /dev/null +++ b/arch/alpha/boot/misc.c @@ -0,0 +1,172 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * misc.c + * + * This is a collection of several routines from gzip-1.0.3 + * adapted for Linux. + * + * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994 + * + * Modified for ARM Linux by Russell King + * + * Nicolas Pitre 1999/04/14 : + * For this code to run directly from Flash, all constant variables must + * be marked with 'const' and all other variables initialized at run-time + * only. This way all non constant variables will end up in the bss segment, + * which should point to addresses in RAM and cleared to 0 on start. + * This allows for a much quicker boot time. + * + * Modified for Alpha, from the ARM version, by Jay Estabrook 2003. + */ + +#include +#include + +#include + +#define memzero(s,n) memset ((s),0,(n)) +#define puts srm_printk +extern long srm_printk(const char *, ...) + __attribute__ ((format (printf, 1, 2))); + +/* + * gzip declarations + */ +#define OF(args) args +#define STATIC static + +typedef unsigned char uch; +typedef unsigned short ush; +typedef unsigned long ulg; + +#define WSIZE 0x8000 /* Window size must be at least 32k, */ + /* and a power of two */ + +static uch *inbuf; /* input buffer */ +static uch *window; /* Sliding window buffer */ + +static unsigned insize; /* valid bytes in inbuf */ +static unsigned inptr; /* index of next byte to be processed in inbuf */ +static unsigned outcnt; /* bytes in output buffer */ + +/* gzip flag byte */ +#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ +#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ +#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ +#define ORIG_NAME 0x08 /* bit 3 set: original file name present */ +#define COMMENT 0x10 /* bit 4 set: file comment present */ +#define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */ +#define RESERVED 0xC0 /* bit 6,7: reserved */ + +#define get_byte() (inptr < insize ? inbuf[inptr++] : fill_inbuf()) + +/* Diagnostic functions */ +#ifdef DEBUG +# define Assert(cond,msg) {if(!(cond)) error(msg);} +# define Trace(x) fprintf x +# define Tracev(x) {if (verbose) fprintf x ;} +# define Tracevv(x) {if (verbose>1) fprintf x ;} +# define Tracec(c,x) {if (verbose && (c)) fprintf x ;} +# define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;} +#else +# define Assert(cond,msg) +# define Trace(x) +# define Tracev(x) +# define Tracevv(x) +# define Tracec(c,x) +# define Tracecv(c,x) +#endif + +static int fill_inbuf(void); +static void flush_window(void); +static void error(char *m); + +static char *input_data; +static int input_data_size; + +static uch *output_data; +static ulg output_ptr; +static ulg bytes_out; + +static void error(char *m); + +extern int end; +static ulg free_mem_ptr; +static ulg free_mem_end_ptr; + +#define HEAP_SIZE 0x3000 + +#include "../../../lib/inflate.c" + +/* =========================================================================== + * Fill the input buffer. This is called only when the buffer is empty + * and at least one byte is really needed. + */ +int fill_inbuf(void) +{ + if (insize != 0) + error("ran out of input data"); + + inbuf = input_data; + insize = input_data_size; + + inptr = 1; + return inbuf[0]; +} + +/* =========================================================================== + * Write the output window window[0..outcnt-1] and update crc and bytes_out. + * (Used for the decompressed data only.) + */ +void flush_window(void) +{ + ulg c = crc; + unsigned n; + uch *in, *out, ch; + + in = window; + out = &output_data[output_ptr]; + for (n = 0; n < outcnt; n++) { + ch = *out++ = *in++; + c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8); + } + crc = c; + bytes_out += (ulg)outcnt; + output_ptr += (ulg)outcnt; + outcnt = 0; +/* puts("."); */ +} + +static void error(char *x) +{ + puts("\n\n"); + puts(x); + puts("\n\n -- System halted"); + + while(1); /* Halt */ +} + +unsigned int +decompress_kernel(void *output_start, + void *input_start, + size_t ksize, + size_t kzsize) +{ + output_data = (uch *)output_start; + input_data = (uch *)input_start; + input_data_size = kzsize; /* use compressed size */ + + /* FIXME FIXME FIXME */ + free_mem_ptr = (ulg)output_start + ksize; + free_mem_end_ptr = (ulg)output_start + ksize + 0x200000; + /* FIXME FIXME FIXME */ + + /* put in temp area to reduce initial footprint */ + window = malloc(WSIZE); + + makecrc(); +/* puts("Uncompressing Linux..."); */ + gunzip(); +/* puts(" done, booting the kernel.\n"); */ + return output_ptr; +} -- cgit v1.3.1