/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: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> --- Documentation/vm/pagemap.txt | 6 ++++- fs/proc/Kconfig | 5 ++-- fs/proc/page.c | 53 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 61 insertions(+), 3 deletions(-) diff --git a/Documentation/vm/pagemap.txt b/Documentation/vm/pagemap.txt index 6bfbc172cdb9..a9b7afc8fbc6 100644 --- a/Documentation/vm/pagemap.txt +++ b/Documentation/vm/pagemap.txt @@ -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 @@ -65,6 +65,10 @@ 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 diff --git a/fs/proc/Kconfig b/fs/proc/Kconfig index 2183fcf41d59..5021a2935bb9 100644 --- a/fs/proc/Kconfig +++ b/fs/proc/Kconfig @@ -69,5 +69,6 @@ config PROC_PAGE_MONITOR help Various /proc files exist to monitor process memory utilization: /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap, - /proc/kpagecount, and /proc/kpageflags. Disabling these - interfaces will reduce the size of the kernel by approximately 4kb. + /proc/kpagecount, /proc/kpageflags, and /proc/kpagecgroup. + Disabling these interfaces will reduce the size of the kernel + by approximately 4kb. diff --git a/fs/proc/page.c b/fs/proc/page.c index 7eee2d8b97d9..70d23245dd43 100644 --- a/fs/proc/page.c +++ b/fs/proc/page.c @@ -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); -- 1.7.10.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>