[RFC][PATCH 9/9] pagemap: export swap ptes
From: Dave Hansen <hidden>
Date: 2007-08-21 20:43:01
In addition to understanding which physical pages are used by a process, it would also be very nice to enumerate how much swap space a process is using. This patch enables /proc/<pid>/pagemap to display swap ptes. In the process, it also changes the constant that we used to indicate non-present ptes before. Signed-off-by: Dave Hansen <redacted> --- lxc-dave/fs/proc/task_mmu.c | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) diff -puN fs/proc/task_mmu.c~pagemap-export-swap-ptes fs/proc/task_mmu.c
--- lxc/fs/proc/task_mmu.c~pagemap-export-swap-ptes 2007-08-21 13:30:55.000000000 -0700
+++ lxc-dave/fs/proc/task_mmu.c 2007-08-21 13:30:55.000000000 -0700@@ -7,6 +7,8 @@ #include <linux/pagemap.h> #include <linux/ptrace.h> #include <linux/mempolicy.h> +#include <linux/swap.h> +#include <linux/swapops.h> #include <asm/elf.h> #include <asm/uaccess.h>
@@ -506,9 +508,13 @@ struct pagemapread { int index; unsigned long __user *out; }; - #define PM_ENTRY_BYTES sizeof(unsigned long) -#define PM_NOT_PRESENT ((unsigned long)-1) +#define PM_RESERVED_BITS 3 +#define PM_RESERVED_OFFSET (BITS_PER_LONG-PM_RESERVED_BITS) +#define PM_RESERVED_MASK (((1<<PM_RESERVED_BITS)-1) << PM_RESERVED_OFFSET) +#define PM_SPECIAL(nr) (((nr) << PM_RESERVED_OFFSET) | PM_RESERVED_MASK) +#define PM_NOT_PRESENT PM_SPECIAL(1) +#define PM_SWAP PM_SPECIAL(2) #define PAGEMAP_END_OF_BUFFER 1 static int add_to_pagemap(unsigned long addr, unsigned long pfn,
@@ -539,6 +545,21 @@ static int pagemap_pte_hole(unsigned lon return err; } +unsigned long swap_pte_to_pagemap_entry(pte_t pte) +{ + unsigned long ret = 0; + swp_entry_t entry = pte_to_swp_entry(pte); + unsigned long offset; + unsigned long swap_file_nr; + + offset = swp_offset(entry); + swap_file_nr = swp_type(entry); + ret = PM_SWAP | swap_file_nr | (offset << MAX_SWAPFILES_SHIFT); + return ret; +} + + + static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, void *private) {
@@ -549,7 +570,9 @@ static int pagemap_pte_range(pmd_t *pmd, pte = pte_offset_map(pmd, addr); for (; addr != end; pte++, addr += PAGE_SIZE) { unsigned long pfn = PM_NOT_PRESENT; - if (pte_present(*pte)) + if (is_swap_pte(*pte)) + pfn = swap_pte_to_pagemap_entry(*pte); + else if (pte_present(*pte)) pfn = pte_pfn(*pte); err = add_to_pagemap(addr, pfn, pm); if (err)
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