Commit 80ae2fdc authored by Vladimir Davydov's avatar Vladimir Davydov Committed by Linus Torvalds

proc: add kpagecgroup file

/proc/kpagecgroup contains a 64-bit inode number of the memory cgroup each
page is charged to, indexed by PFN.  Having this information is useful for
estimating a cgroup working set size.

The file is present if CONFIG_PROC_PAGE_MONITOR && CONFIG_MEMCG.
Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
Reviewed-by: default avatarAndres Lagar-Cavilla <andreslc@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Greg Thelen <gthelen@google.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e993d905
......@@ -5,7 +5,7 @@ pagemap is a new (as of 2.6.25) set of interfaces in the kernel that allow
userspace programs to examine the page tables and related information by
reading files in /proc.
There are three components to pagemap:
There are four components to pagemap:
* /proc/pid/pagemap. This file lets a userspace process find out which
physical frame each virtual page is mapped to. It contains one 64-bit
......@@ -71,6 +71,10 @@ There are three components to pagemap:
23. BALLOON
24. ZERO_PAGE
* /proc/kpagecgroup. This file contains a 64-bit inode number of the
memory cgroup each page is charged to, indexed by PFN. Only available when
CONFIG_MEMCG is set.
Short descriptions to the page flags:
0. LOCKED
......
......@@ -9,6 +9,7 @@
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/hugetlb.h>
#include <linux/memcontrol.h>
#include <linux/kernel-page-flags.h>
#include <asm/uaccess.h>
#include "internal.h"
......@@ -225,10 +226,62 @@ static const struct file_operations proc_kpageflags_operations = {
.read = kpageflags_read,
};
#ifdef CONFIG_MEMCG
static ssize_t kpagecgroup_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
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;
count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
if (src & KPMMASK || count & KPMMASK)
return -EINVAL;
while (count > 0) {
if (pfn_valid(pfn))
ppage = pfn_to_page(pfn);
else
ppage = NULL;
if (ppage)
ino = page_cgroup_ino(ppage);
else
ino = 0;
if (put_user(ino, out)) {
ret = -EFAULT;
break;
}
pfn++;
out++;
count -= KPMSIZE;
}
*ppos += (char __user *)out - buf;
if (!ret)
ret = (char __user *)out - buf;
return ret;
}
static const struct file_operations proc_kpagecgroup_operations = {
.llseek = mem_lseek,
.read = kpagecgroup_read,
};
#endif /* CONFIG_MEMCG */
static int __init proc_page_init(void)
{
proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations);
proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
#ifdef CONFIG_MEMCG
proc_create("kpagecgroup", S_IRUSR, NULL, &proc_kpagecgroup_operations);
#endif
return 0;
}
fs_initcall(proc_page_init);
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