Re: [patch] tools, vm: new option to specify kpageflags file

From: Naoya Horiguchi
Date: Tue Jan 30 2018 - 21:02:05 EST


On 01/31/2018 08:01 AM, David Rientjes wrote:
> page-types currently hardcodes /proc/kpageflags as the file to parse.
> This works when using the tool to examine the state of pageflags on the
> same system, but does not allow storing a snapshot of pageflags at a given
> time to debug issues nor on a different system.
>
> This allows the user to specify a saved version of kpageflags with a new
> page-types -F option.
>
> Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>

Thanks for the work, looks good to me.

Reviewed-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>

one nitpicking below ...

> ---
> tools/vm/page-types.c | 26 ++++++++++++++++++++------
> 1 file changed, 20 insertions(+), 6 deletions(-)
>
> diff --git a/tools/vm/page-types.c b/tools/vm/page-types.c
> --- a/tools/vm/page-types.c
> +++ b/tools/vm/page-types.c
> @@ -172,6 +172,7 @@ static pid_t opt_pid; /* process to walk */
> const char * opt_file; /* file or directory path */
> static uint64_t opt_cgroup; /* cgroup inode */
> static int opt_list_cgroup;/* list page cgroup */
> +static const char * opt_kpageflags; /* kpageflags file to parse */

checkpatch.pl emits a warning.

ERROR: "foo * bar" should be "foo *bar"
#101: FILE: tools/vm/page-types.c:175:
+static const char * opt_kpageflags; /* kpageflags file to parse */


Thanks,
Naoya Horiguchi

>
> #define MAX_ADDR_RANGES 1024
> static int nr_addr_ranges;
> @@ -258,7 +259,7 @@ static int checked_open(const char *pathname, int flags)
> * pagemap/kpageflags routines
> */
>
> -static unsigned long do_u64_read(int fd, char *name,
> +static unsigned long do_u64_read(int fd, const char *name,
> uint64_t *buf,
> unsigned long index,
> unsigned long count)
> @@ -283,7 +284,7 @@ static unsigned long kpageflags_read(uint64_t *buf,
> unsigned long index,
> unsigned long pages)
> {
> - return do_u64_read(kpageflags_fd, PROC_KPAGEFLAGS, buf, index, pages);
> + return do_u64_read(kpageflags_fd, opt_kpageflags, buf, index, pages);
> }
>
> static unsigned long kpagecgroup_read(uint64_t *buf,
> @@ -293,7 +294,7 @@ static unsigned long kpagecgroup_read(uint64_t *buf,
> if (kpagecgroup_fd < 0)
> return pages;
>
> - return do_u64_read(kpagecgroup_fd, PROC_KPAGEFLAGS, buf, index, pages);
> + return do_u64_read(kpagecgroup_fd, opt_kpageflags, buf, index, pages);
> }
>
> static unsigned long pagemap_read(uint64_t *buf,
> @@ -743,7 +744,7 @@ static void walk_addr_ranges(void)
> {
> int i;
>
> - kpageflags_fd = checked_open(PROC_KPAGEFLAGS, O_RDONLY);
> + kpageflags_fd = checked_open(opt_kpageflags, O_RDONLY);
>
> if (!nr_addr_ranges)
> add_addr_range(0, ULONG_MAX);
> @@ -790,6 +791,7 @@ static void usage(void)
> " -N|--no-summary Don't show summary info\n"
> " -X|--hwpoison hwpoison pages\n"
> " -x|--unpoison unpoison pages\n"
> +" -F|--kpageflags kpageflags file to parse\n"
> " -h|--help Show this usage message\n"
> "flags:\n"
> " 0x10 bitfield format, e.g.\n"
> @@ -1013,7 +1015,7 @@ static void walk_page_cache(void)
> {
> struct stat st;
>
> - kpageflags_fd = checked_open(PROC_KPAGEFLAGS, O_RDONLY);
> + kpageflags_fd = checked_open(opt_kpageflags, O_RDONLY);
> pagemap_fd = checked_open("/proc/self/pagemap", O_RDONLY);
> sigaction(SIGBUS, &sigbus_action, NULL);
>
> @@ -1164,6 +1166,11 @@ static void parse_bits_mask(const char *optarg)
> add_bits_filter(mask, bits);
> }
>
> +static void parse_kpageflags(const char *name)
> +{
> + opt_kpageflags = name;
> +}
> +
> static void describe_flags(const char *optarg)
> {
> uint64_t flags = parse_flag_names(optarg, 0);
> @@ -1188,6 +1195,7 @@ static const struct option opts[] = {
> { "no-summary", 0, NULL, 'N' },
> { "hwpoison" , 0, NULL, 'X' },
> { "unpoison" , 0, NULL, 'x' },
> + { "kpageflags", 0, NULL, 'F' },
> { "help" , 0, NULL, 'h' },
> { NULL , 0, NULL, 0 }
> };
> @@ -1199,7 +1207,7 @@ int main(int argc, char *argv[])
> page_size = getpagesize();
>
> while ((c = getopt_long(argc, argv,
> - "rp:f:a:b:d:c:ClLNXxh", opts, NULL)) != -1) {
> + "rp:f:a:b:d:c:ClLNXxF:h", opts, NULL)) != -1) {
> switch (c) {
> case 'r':
> opt_raw = 1;
> @@ -1242,6 +1250,9 @@ int main(int argc, char *argv[])
> opt_unpoison = 1;
> prepare_hwpoison_fd();
> break;
> + case 'F':
> + parse_kpageflags(optarg);
> + break;
> case 'h':
> usage();
> exit(0);
> @@ -1251,6 +1262,9 @@ int main(int argc, char *argv[])
> }
> }
>
> + if (!opt_kpageflags)
> + opt_kpageflags = PROC_KPAGEFLAGS;
> +
> if (opt_cgroup || opt_list_cgroup)
> kpagecgroup_fd = checked_open(PROC_KPAGECGROUP, O_RDONLY);
>
>