[Crash-utility] Re: [RFC PATCH 1/2] add cpu_to_nid function

Hi Huang, On Mon, Jul 20, 2026 at 8:52 PM Huang Shijie <huangsj(a)hygon.cn&gt; wrote: > > Add cpu_to_nid function which we can use to get the NUMA node id > by the cpu id. > > Signed-off-by: Huang Shijie <huangsj(a)hygon.cn&gt; > --- > defs.h | 2 ++ > kernel.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ > main.c | 1 + > 3 files changed, 49 insertions(+) > > diff --git a/defs.h b/defs.h > index a4f70b7..98a149b 100644 > --- a/defs.h > +++ b/defs.h > @@ -6040,6 +6040,8 @@ ulong do_maple_tree(ulong, int, struct list_pair *); > void help_init(void); > void cmd_usage(char *, int); > void display_version(void); > +int cpu_to_nid(int cpu); > +void numa_init(void); > void display_help_screen(char *); > #ifdef ARM > #define dump_machdep_table(X) arm_dump_machdep_table(X) > diff --git a/kernel.c b/kernel.c > index eb9754c..15254a4 100644 > --- a/kernel.c > +++ b/kernel.c > @@ -12207,3 +12207,49 @@ out: > pc->error_fp = error_fp_save; > } > #endif > + > +static int *cpu_to_nid_map; > + > +int > +cpu_to_nid(int cpu) > +{ > + if (!cpu_to_nid_map || cpu < 0 || cpu >= kt->cpus) > + return -1; > + if (vt->numnodes == 1) > + return 0; > + return cpu_to_nid_map[cpu]; > +} > + > +static void > +cpu_to_nid_init(void) > +{ > + int i, j; > + int fd; > + char buf[64]; > + > + cpu_to_nid_map = malloc(kt->cpus * sizeof(int)); > + if (vt->numnodes == 1) > + return; > + > + memset(cpu_to_nid_map, -1, kt->cpus * sizeof(int)); > + > + for (i = 0; i < kt->cpus; i++) { > + for (j = 0; j < vt->numnodes; j++) { > + memset(buf, 0, sizeof(buf)); > + sprintf(buf, "/sys/devices/system/cpu/cpu%d/node%d", i, j); This will only work for live debug, rather than vmcore debug, won't it? If so, I suggest supporting vmcore debug as well, so we can remove the "/sys" dir reading.