Commit a40b3fa8 authored by Liu Ye's avatar Liu Ye Committed by Andrew Morton
Browse files

fs/proc/page: refactor to reduce code duplication 

kpageflags_read() and kpagecgroup_read() are quite similar to
kpagecount_read().  Refactor common code into a helper function to reduce
code duplication.

Link: https://lkml.kernel.org/r/20250318063226.223284-1-liuyerd@163.com


Signed-off-by: default avatarLiu Ye <liuye@kylinos.cn>
Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Svetly Todorov <svetly.todorov@memverge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 4c97a17a

fs/proc/page.c

+54 −107
Original line number Diff line number Diff line
@@ -22,6 +22,12 @@ 
#define KPMMASK (KPMSIZE - 1)

#define KPMBITS (KPMSIZE * BITS_PER_BYTE)



enum kpage_operation {

	KPAGE_FLAGS,

	KPAGE_COUNT,

	KPAGE_CGROUP,

};



static inline unsigned long get_max_dump_pfn(void)

{

#ifdef CONFIG_SPARSEMEM
@@ -37,19 +43,17 @@ static inline unsigned long get_max_dump_pfn(void) 
#endif

}



/* /proc/kpagecount - an array exposing page mapcounts

 *

 * Each entry is a u64 representing the corresponding

 * physical page mapcount.

 */

static ssize_t kpagecount_read(struct file *file, char __user *buf,

			     size_t count, loff_t *ppos)

static ssize_t kpage_read(struct file *file, char __user *buf,

		size_t count, loff_t *ppos,

		enum kpage_operation op)

{

	const unsigned long max_dump_pfn = get_max_dump_pfn();

	u64 __user *out = (u64 __user *)buf;

	struct page *page;

	unsigned long src = *ppos;

	unsigned long pfn;

	ssize_t ret = 0;

	u64 info;



	pfn = src / KPMSIZE;

	if (src & KPMMASK || count & KPMMASK)
@@ -59,24 +63,34 @@ static ssize_t kpagecount_read(struct file *file, char __user *buf, 
	count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);



	while (count > 0) {

		struct page *page;

		u64 mapcount = 0;



		/*

		 * TODO: ZONE_DEVICE support requires to identify

		 * memmaps that were actually initialized.

		 */

		page = pfn_to_online_page(pfn);

		if (page) {

			struct folio *folio = page_folio(page);



		if (page) {

			switch (op) {

			case KPAGE_FLAGS:

				info = stable_page_flags(page);

				break;

			case KPAGE_COUNT:

				if (IS_ENABLED(CONFIG_PAGE_MAPCOUNT))

				mapcount = folio_precise_page_mapcount(folio, page);

					info = folio_precise_page_mapcount(page_folio(page), page);

				else

				mapcount = folio_average_page_mapcount(folio);

					info = folio_average_page_mapcount(page_folio(page));

				break;

			case KPAGE_CGROUP:

				info = page_cgroup_ino(page);

				break;

			default:

				info = 0;

				break;

			}

		} else

			info = 0;



		if (put_user(mapcount, out)) {

		if (put_user(info, out)) {

			ret = -EFAULT;

			break;

		}
@@ -94,17 +108,23 @@ static ssize_t kpagecount_read(struct file *file, char __user *buf, 
	return ret;

}



/* /proc/kpagecount - an array exposing page mapcounts

 *

 * Each entry is a u64 representing the corresponding

 * physical page mapcount.

 */

static ssize_t kpagecount_read(struct file *file, char __user *buf,

		size_t count, loff_t *ppos)

{

	return kpage_read(file, buf, count, ppos, KPAGE_COUNT);

}



static const struct proc_ops kpagecount_proc_ops = {

	.proc_flags	= PROC_ENTRY_PERMANENT,

	.proc_lseek	= mem_lseek,

	.proc_read	= kpagecount_read,

};



/* /proc/kpageflags - an array exposing page flags

 *

 * Each entry is a u64 representing the corresponding

 * physical page flags.

 */



static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit)

{
@@ -225,47 +245,17 @@ u64 stable_page_flags(const struct page *page) 
#endif



	return u;

};

}



/* /proc/kpageflags - an array exposing page flags

 *

 * Each entry is a u64 representing the corresponding

 * physical page flags.

 */

static ssize_t kpageflags_read(struct file *file, char __user *buf,

		size_t count, loff_t *ppos)

{

	const unsigned long max_dump_pfn = get_max_dump_pfn();

	u64 __user *out = (u64 __user *)buf;

	unsigned long src = *ppos;

	unsigned long pfn;

	ssize_t ret = 0;



	pfn = src / KPMSIZE;

	if (src & KPMMASK || count & KPMMASK)

		return -EINVAL;

	if (src >= max_dump_pfn * KPMSIZE)

		return 0;

	count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);



	while (count > 0) {

		/*

		 * TODO: ZONE_DEVICE support requires to identify

		 * memmaps that were actually initialized.

		 */

		struct page *page = pfn_to_online_page(pfn);



		if (put_user(stable_page_flags(page), out)) {

			ret = -EFAULT;

			break;

		}



		pfn++;

		out++;

		count -= KPMSIZE;



		cond_resched();

	}



	*ppos += (char __user *)out - buf;

	if (!ret)

		ret = (char __user *)out - buf;

	return ret;

	return kpage_read(file, buf, count, ppos, KPAGE_FLAGS);

}



static const struct proc_ops kpageflags_proc_ops = {
@@ -278,51 +268,8 @@ static const struct proc_ops kpageflags_proc_ops = { 
static ssize_t kpagecgroup_read(struct file *file, char __user *buf,

		size_t count, loff_t *ppos)

{

	const unsigned long max_dump_pfn = get_max_dump_pfn();

	u64 __user *out = (u64 __user *)buf;

	struct page *ppage;

	unsigned long src = *ppos;

	unsigned long pfn;

	ssize_t ret = 0;

	u64 ino;



	pfn = src / KPMSIZE;

	if (src & KPMMASK || count & KPMMASK)

		return -EINVAL;

	if (src >= max_dump_pfn * KPMSIZE)

		return 0;

	count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);



	while (count > 0) {

		/*

		 * TODO: ZONE_DEVICE support requires to identify

		 * memmaps that were actually initialized.

		 */

		ppage = pfn_to_online_page(pfn);



		if (ppage)

			ino = page_cgroup_ino(ppage);

		else

			ino = 0;



		if (put_user(ino, out)) {

			ret = -EFAULT;

			break;

	return kpage_read(file, buf, count, ppos, KPAGE_CGROUP);

}



		pfn++;

		out++;

		count -= KPMSIZE;



		cond_resched();

	}



	*ppos += (char __user *)out - buf;

	if (!ret)

		ret = (char __user *)out - buf;

	return ret;

}



static const struct proc_ops kpagecgroup_proc_ops = {

	.proc_flags	= PROC_ENTRY_PERMANENT,

	.proc_lseek	= mem_lseek,

include/linux/memcontrol.h

+4 −0
Original line number Diff line number Diff line
@@ -1793,6 +1793,10 @@ static inline void count_objcg_events(struct obj_cgroup *objcg, 
{

}



static inline ino_t page_cgroup_ino(struct page *page)

{

	return 0;

}

#endif /* CONFIG_MEMCG */



#if defined(CONFIG_MEMCG) && defined(CONFIG_ZSWAP)