On Thu, 2021-01-28 at 10:19 +0800, Yafang Shao wrote:
> Currently the pGp only shows the names of page flags, rather than
> the full information including section, node, zone, last cpupid and
> kasan tag. While it is not easy to parse these information manually
> because there're so many flavors. Let's interpret them in pGp as well.
[]
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
[]
> @@ -1916,6 +1916,46 @@ char *format_flags(char *buf, char *end, unsigned long
> flags,
> return buf;
> }
>
> +struct page_flags_layout {
> + int width;
> + int shift;
> + int mask;
> + char *name;
> +};
> +
> +struct page_flags_layout pfl[] = {
static const struct page_flags_layout pfl[] = {
> + {SECTIONS_WIDTH, SECTIONS_PGSHIFT, SECTIONS_MASK, "Section "},
> + {NODES_WIDTH, NODES_PGSHIFT, NODES_MASK, "Node "},
> + {ZONES_WIDTH, ZONES_PGSHIFT, ZONES_MASK, "Zone "},
> + {LAST_CPUPID_WIDTH, LAST_CPUPID_PGSHIFT, LAST_CPUPID_MASK, "Lastcpupid
> "},
> + {KASAN_TAG_WIDTH, KASAN_TAG_PGSHIFT, KASAN_TAG_MASK, "Kasantag "},
> +};
> +
> +static
> +char *format_layout(char *buf, char *end, unsigned long flags)
poor name. perhaps format_page_flags
> +{
> + int i;
> +
> + for (i = 0; i < sizeof(pfl) / sizeof(struct page_flags_layout) && buf <
> end; i++) {
for (i = 0; i < ARRAY_SIZE(pfl) && buf < end; i++) {
> @@ -1929,7 +1969,7 @@ char *flags_string(char *buf, char *end, void
> *flags_ptr,
> switch (fmt[1]) {
> case 'p':
> flags = *(unsigned long *)flags_ptr;
> - /* Remove zone id */
> + buf = format_layout(buf, end, flags & ~((1UL << NR_PAGEFLAGS) -
> 1));
> flags &= (1UL << NR_PAGEFLAGS) - 1;
Perhaps store the bitshift into a temp and use the temp twice
foo = BIT(NR_PAGEFLAGS) - 1;
buf = format_layout(buf, end, flags & ~foo);
flags &= foo;
