mm: add PG_pool in /proc/kpageflags

hulk inclusion
category: feature
bugzilla: 46904, https://gitee.com/openeuler/kernel/issues/I4RO84
CVE: NA

--------------------------------

Export PG_pool page flag in /proc/kpageflags.

	27. KPF_POOL		page is allocated from hpool.

By using this tool, we can easily count the number of pages allocated from
dynamic hugetlb pool by a process or a file.
Signed-off-by: NLiu Shixin <liushixin2@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

fs/proc/page.c

@@ -220,6 +220,7 @@ u64 stable_page_flags(struct page *page)
 #ifdef CONFIG_64BIT
 	u |= kpf_copy_bit(k, KPF_ARCH_2,	PG_arch_2);
 #endif
+	u |= kpf_copy_bit(k, KPF_POOL,		PG_pool);
 
 	return u;
 };

include/uapi/linux/kernel-page-flags.h

@@ -36,5 +36,6 @@
 #define KPF_ZERO_PAGE		24
 #define KPF_IDLE		25
 #define KPF_PGTABLE		26
+#define KPF_POOL		27
 
 #endif /* _UAPILINUX_KERNEL_PAGE_FLAGS_H */

tools/vm/page-types.c

@@ -126,6 +126,7 @@ static const char * const page_flag_names[] = {
 	[KPF_PGTABLE]		= "g:pgtable",
 	[KPF_ZERO_PAGE]		= "z:zero_page",
 	[KPF_IDLE]              = "i:idle_page",
+	[KPF_POOL]              = "h:hpool",
 
 	[KPF_RESERVED]		= "r:reserved",
 	[KPF_MLOCKED]		= "m:mlocked",