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Message-Id: <11.430487409@selenic.com> Date: Fri, 26 Oct 2007 11:36:36 -0500 From: Matt Mackall <mpm@...enic.com> To: Andrew Morton <akpm@...ux-foundation.org>, linux-kernel@...r.kernel.org Cc: Dave Hansen <haveblue@...ibm.com>, Rusty Russell <rusty@...tcorp.com.au>, Jeremy Fitzhardinge <jeremy@...p.org>, David Rientjes <rientjes@...gle.com>, Fengguang Wu <wfg@...l.ustc.edu.cn> Subject: [PATCH 10/12] maps4: add /proc/kpagecount interface From: Matt Mackall <mpm@...enic.com> This makes physical page map counts available to userspace. Together with /proc/pid/pagemap and /proc/pid/clear_refs, this can be used to monitor memory usage on a per-page basis. [bunk@...sta.de: make struct proc_kpagemap static] Signed-off-by: Matt Mackall <mpm@...enic.com> Cc: Jeremy Fitzhardinge <jeremy@...p.org> Cc: David Rientjes <rientjes@...gle.com> Signed-off-by: Adrian Bunk <bunk@...sta.de> Signed-off-by: Andrew Morton <akpm@...ux-foundation.org> --- Index: l/fs/proc/proc_misc.c =================================================================== --- l.orig/fs/proc/proc_misc.c 2007-10-22 16:24:34.000000000 -0500 +++ l/fs/proc/proc_misc.c 2007-10-22 17:53:48.000000000 -0500 @@ -46,6 +46,7 @@ #include <linux/vmalloc.h> #include <linux/crash_dump.h> #include <linux/pid_namespace.h> +#include <linux/bootmem.h> #include <asm/uaccess.h> #include <asm/pgtable.h> #include <asm/io.h> @@ -656,6 +657,57 @@ static const struct file_operations proc }; #endif +#define KPMSIZE sizeof(u64) +#define KPMMASK (KPMSIZE - 1) +/* /proc/kpagecount - an array exposing page counts + * + * Each entry is a u64 representing the corresponding + * physical page count. + */ +static ssize_t kpagecount_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 pcount; + + if (!access_ok(VERIFY_WRITE, buf, count)) + return -EFAULT; + + pfn = src / KPMSIZE; + count = min_t(size_t, count, (max_pfn * KPMSIZE) - src); + if (src & KPMMASK || count & KPMMASK) + return -EIO; + + while (count > 0) { + ppage = pfn_to_page(pfn++); + if (!ppage) + pcount = 0; + else + pcount = atomic_read(&ppage->_count); + + if (put_user(pcount, out++)) { + ret = -EFAULT; + break; + } + + count -= KPMSIZE; + } + + *ppos += (char __user *)out - buf; + if (!ret) + ret = (char __user *)out - buf; + return ret; +} + +static struct file_operations proc_kpagecount_operations = { + .llseek = mem_lseek, + .read = kpagecount_read, +}; + struct proc_dir_entry *proc_root_kcore; void create_seq_entry(char *name, mode_t mode, const struct file_operations *f) @@ -735,6 +787,7 @@ void __init proc_misc_init(void) (size_t)high_memory - PAGE_OFFSET + PAGE_SIZE; } #endif + create_seq_entry("kpagecount", S_IRUSR, &proc_kpagecount_operations); #ifdef CONFIG_PROC_VMCORE proc_vmcore = create_proc_entry("vmcore", S_IRUSR, NULL); if (proc_vmcore) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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