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fs/proc/page: refactor to reduce code duplication

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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: Liu Ye <liuye@kylinos.cn>
Acked-by: David 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: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Liu Ye
2025-03-18 14:32:26 +08:00
committed by Andrew Morton
parent 4c97a17a25
commit a40b3fa844
2 changed files with 57 additions and 106 deletions
Download Patch File Download Diff File Expand all files Collapse all files

159
fs/proc/page.c
View File

@@ -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);
switch (op) {
case KPAGE_FLAGS:
info = stable_page_flags(page);
break;
case KPAGE_COUNT:
if (IS_ENABLED(CONFIG_PAGE_MAPCOUNT))
info = folio_precise_page_mapcount(page_folio(page), page);
else
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 (IS_ENABLED(CONFIG_PAGE_MAPCOUNT))
mapcount = folio_precise_page_mapcount(folio, page);
else
mapcount = folio_average_page_mapcount(folio);
}
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)
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 = {
@@ -276,53 +266,10 @@ static const struct proc_ops kpageflags_proc_ops = {
#ifdef CONFIG_MEMCG
static ssize_t kpagecgroup_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
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;
}
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_CGROUP);
}
static const struct proc_ops kpagecgroup_proc_ops = {
.proc_flags = PROC_ENTRY_PERMANENT,
.proc_lseek = mem_lseek,

4
include/linux/memcontrol.h
View File

@@ -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)