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21 results

page-types.c

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  • Forked from André Almeida / linux
    Source project has a limited visibility.
    page-types.c 30.42 KiB
    /*
     * page-types: Tool for querying page flags
     *
     * This program is free software; you can redistribute it and/or modify it
     * under the terms of the GNU General Public License as published by the Free
     * Software Foundation; version 2.
     *
     * This program is distributed in the hope that it will be useful, but WITHOUT
     * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
     * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
     * more details.
     *
     * You should find a copy of v2 of the GNU General Public License somewhere on
     * your Linux system; if not, write to the Free Software Foundation, Inc., 59
     * Temple Place, Suite 330, Boston, MA 02111-1307 USA.
     *
     * Copyright (C) 2009 Intel corporation
     *
     * Authors: Wu Fengguang <fengguang.wu@intel.com>
     */
    
    #define _FILE_OFFSET_BITS 64
    #define _GNU_SOURCE
    #include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <stdint.h>
    #include <stdarg.h>
    #include <string.h>
    #include <getopt.h>
    #include <limits.h>
    #include <assert.h>
    #include <ftw.h>
    #include <time.h>
    #include <setjmp.h>
    #include <signal.h>
    #include <sys/types.h>
    #include <sys/errno.h>
    #include <sys/fcntl.h>
    #include <sys/mount.h>
    #include <sys/statfs.h>
    #include <sys/mman.h>
    #include "../../include/uapi/linux/magic.h"
    #include "../../include/uapi/linux/kernel-page-flags.h"
    #include <api/fs/fs.h>
    
    #ifndef MAX_PATH
    # define MAX_PATH 256
    #endif
    
    #ifndef STR
    # define _STR(x) #x
    # define STR(x) _STR(x)
    #endif
    
    /*
     * pagemap kernel ABI bits
     */
    
    #define PM_ENTRY_BYTES		8
    #define PM_PFRAME_BITS		55
    #define PM_PFRAME_MASK		((1LL << PM_PFRAME_BITS) - 1)
    #define PM_PFRAME(x)		((x) & PM_PFRAME_MASK)
    #define MAX_SWAPFILES_SHIFT	5
    #define PM_SWAP_OFFSET(x)	(((x) & PM_PFRAME_MASK) >> MAX_SWAPFILES_SHIFT)
    #define PM_SOFT_DIRTY		(1ULL << 55)
    #define PM_MMAP_EXCLUSIVE	(1ULL << 56)
    #define PM_FILE			(1ULL << 61)
    #define PM_SWAP			(1ULL << 62)
    #define PM_PRESENT		(1ULL << 63)
    
    /*
     * kernel page flags
     */
    
    #define KPF_BYTES		8
    #define PROC_KPAGEFLAGS		"/proc/kpageflags"
    #define PROC_KPAGECOUNT		"/proc/kpagecount"
    #define PROC_KPAGECGROUP	"/proc/kpagecgroup"
    
    #define SYS_KERNEL_MM_PAGE_IDLE "/sys/kernel/mm/page_idle/bitmap"
    
    /* [32-] kernel hacking assistances */
    #define KPF_RESERVED		32
    #define KPF_MLOCKED		33
    #define KPF_MAPPEDTODISK	34
    #define KPF_PRIVATE		35
    #define KPF_PRIVATE_2		36
    #define KPF_OWNER_PRIVATE	37
    #define KPF_ARCH		38
    #define KPF_UNCACHED		39
    #define KPF_SOFTDIRTY		40
    
    /* [48-] take some arbitrary free slots for expanding overloaded flags
     * not part of kernel API
     */
    #define KPF_READAHEAD		48
    #define KPF_SLOB_FREE		49
    #define KPF_SLUB_FROZEN		50
    #define KPF_SLUB_DEBUG		51
    #define KPF_FILE		61
    #define KPF_SWAP		62
    #define KPF_MMAP_EXCLUSIVE	63
    
    #define KPF_ALL_BITS		((uint64_t)~0ULL)
    #define KPF_HACKERS_BITS	(0xffffULL << 32)
    #define KPF_OVERLOADED_BITS	(0xffffULL << 48)
    #define BIT(name)		(1ULL << KPF_##name)
    #define BITS_COMPOUND		(BIT(COMPOUND_HEAD) | BIT(COMPOUND_TAIL))
    
    static const char * const page_flag_names[] = {
    	[KPF_LOCKED]		= "L:locked",
    	[KPF_ERROR]		= "E:error",
    	[KPF_REFERENCED]	= "R:referenced",
    	[KPF_UPTODATE]		= "U:uptodate",
    	[KPF_DIRTY]		= "D:dirty",
    	[KPF_LRU]		= "l:lru",
    	[KPF_ACTIVE]		= "A:active",
    	[KPF_SLAB]		= "S:slab",
    	[KPF_WRITEBACK]		= "W:writeback",
    	[KPF_RECLAIM]		= "I:reclaim",
    	[KPF_BUDDY]		= "B:buddy",
    
    	[KPF_MMAP]		= "M:mmap",
    	[KPF_ANON]		= "a:anonymous",
    	[KPF_SWAPCACHE]		= "s:swapcache",
    	[KPF_SWAPBACKED]	= "b:swapbacked",
    	[KPF_COMPOUND_HEAD]	= "H:compound_head",
    	[KPF_COMPOUND_TAIL]	= "T:compound_tail",
    	[KPF_HUGE]		= "G:huge",
    	[KPF_UNEVICTABLE]	= "u:unevictable",
    	[KPF_HWPOISON]		= "X:hwpoison",
    	[KPF_NOPAGE]		= "n:nopage",
    	[KPF_KSM]		= "x:ksm",
    	[KPF_THP]		= "t:thp",
    	[KPF_BALLOON]		= "o:balloon",
    	[KPF_PGTABLE]		= "g:pgtable",
    	[KPF_ZERO_PAGE]		= "z:zero_page",
    	[KPF_IDLE]              = "i:idle_page",
    
    	[KPF_RESERVED]		= "r:reserved",
    	[KPF_MLOCKED]		= "m:mlocked",
    	[KPF_MAPPEDTODISK]	= "d:mappedtodisk",
    	[KPF_PRIVATE]		= "P:private",
    	[KPF_PRIVATE_2]		= "p:private_2",
    	[KPF_OWNER_PRIVATE]	= "O:owner_private",
    	[KPF_ARCH]		= "h:arch",
    	[KPF_UNCACHED]		= "c:uncached",
    	[KPF_SOFTDIRTY]		= "f:softdirty",
    
    	[KPF_READAHEAD]		= "I:readahead",
    	[KPF_SLOB_FREE]		= "P:slob_free",
    	[KPF_SLUB_FROZEN]	= "A:slub_frozen",
    	[KPF_SLUB_DEBUG]	= "E:slub_debug",
    
    	[KPF_FILE]		= "F:file",
    	[KPF_SWAP]		= "w:swap",
    	[KPF_MMAP_EXCLUSIVE]	= "1:mmap_exclusive",
    };
    
    
    /*
     * data structures
     */
    
    static int		opt_raw;	/* for kernel developers */
    static int		opt_list;	/* list pages (in ranges) */
    static int		opt_mark_idle;	/* set accessed bit */
    static int		opt_no_summary;	/* don't show summary */
    static pid_t		opt_pid;	/* process to walk */
    const char		*opt_file;	/* file or directory path */
    static uint64_t		opt_cgroup;	/* cgroup inode */
    static int		opt_list_cgroup;/* list page cgroup */
    static int		opt_list_mapcnt;/* list page map count */
    static const char	*opt_kpageflags;/* kpageflags file to parse */
    
    #define MAX_ADDR_RANGES	1024
    static int		nr_addr_ranges;
    static unsigned long	opt_offset[MAX_ADDR_RANGES];
    static unsigned long	opt_size[MAX_ADDR_RANGES];
    
    #define MAX_VMAS	10240
    static int		nr_vmas;
    static unsigned long	pg_start[MAX_VMAS];
    static unsigned long	pg_end[MAX_VMAS];
    
    #define MAX_BIT_FILTERS	64
    static int		nr_bit_filters;
    static uint64_t		opt_mask[MAX_BIT_FILTERS];
    static uint64_t		opt_bits[MAX_BIT_FILTERS];
    
    static int		page_size;
    
    static int		pagemap_fd;
    static int		kpageflags_fd;
    static int		kpagecount_fd = -1;
    static int		kpagecgroup_fd = -1;
    static int		page_idle_fd = -1;
    
    static int		opt_hwpoison;
    static int		opt_unpoison;
    
    static const char	*hwpoison_debug_fs;
    static int		hwpoison_inject_fd;
    static int		hwpoison_forget_fd;
    
    #define HASH_SHIFT	13
    #define HASH_SIZE	(1 << HASH_SHIFT)
    #define HASH_MASK	(HASH_SIZE - 1)
    #define HASH_KEY(flags)	(flags & HASH_MASK)
    
    static unsigned long	total_pages;
    static unsigned long	nr_pages[HASH_SIZE];
    static uint64_t		page_flags[HASH_SIZE];
    
    
    /*
     * helper functions
     */
    
    #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
    
    #define min_t(type, x, y) ({			\
    	type __min1 = (x);			\
    	type __min2 = (y);			\
    	__min1 < __min2 ? __min1 : __min2; })
    
    #define max_t(type, x, y) ({			\
    	type __max1 = (x);			\
    	type __max2 = (y);			\
    	__max1 > __max2 ? __max1 : __max2; })
    
    static unsigned long pages2mb(unsigned long pages)
    {
    	return (pages * page_size) >> 20;
    }
    
    static void fatal(const char *x, ...)
    {
    	va_list ap;
    
    	va_start(ap, x);
    	vfprintf(stderr, x, ap);
    	va_end(ap);
    	exit(EXIT_FAILURE);
    }
    
    static int checked_open(const char *pathname, int flags)
    {
    	int fd = open(pathname, flags);
    
    	if (fd < 0) {
    		perror(pathname);
    		exit(EXIT_FAILURE);
    	}
    
    	return fd;
    }
    
    /*
     * pagemap/kpageflags routines
     */
    
    static unsigned long do_u64_read(int fd, const char *name,
    				 uint64_t *buf,
    				 unsigned long index,
    				 unsigned long count)
    {
    	long bytes;
    
    	if (index > ULONG_MAX / 8)
    		fatal("index overflow: %lu\n", index);
    
    	bytes = pread(fd, buf, count * 8, (off_t)index * 8);
    	if (bytes < 0) {
    		perror(name);
    		exit(EXIT_FAILURE);
    	}
    	if (bytes % 8)
    		fatal("partial read: %lu bytes\n", bytes);
    
    	return bytes / 8;
    }
    
    static unsigned long kpageflags_read(uint64_t *buf,
    				     unsigned long index,
    				     unsigned long pages)
    {
    	return do_u64_read(kpageflags_fd, opt_kpageflags, buf, index, pages);
    }
    
    static unsigned long kpagecgroup_read(uint64_t *buf,
    				      unsigned long index,
    				      unsigned long pages)
    {
    	if (kpagecgroup_fd < 0)
    		return pages;
    
    	return do_u64_read(kpagecgroup_fd, opt_kpageflags, buf, index, pages);
    }
    
    static unsigned long kpagecount_read(uint64_t *buf,
    				     unsigned long index,
    				     unsigned long pages)
    {
    	return kpagecount_fd < 0 ? pages :
    		do_u64_read(kpagecount_fd, PROC_KPAGECOUNT,
    			    buf, index, pages);
    }
    
    static unsigned long pagemap_read(uint64_t *buf,
    				  unsigned long index,
    				  unsigned long pages)
    {
    	return do_u64_read(pagemap_fd, "/proc/pid/pagemap", buf, index, pages);
    }
    
    static unsigned long pagemap_pfn(uint64_t val)
    {
    	unsigned long pfn;
    
    	if (val & PM_PRESENT)
    		pfn = PM_PFRAME(val);
    	else
    		pfn = 0;
    
    	return pfn;
    }
    
    static unsigned long pagemap_swap_offset(uint64_t val)
    {
    	return val & PM_SWAP ? PM_SWAP_OFFSET(val) : 0;
    }
    
    /*
     * page flag names
     */
    
    static char *page_flag_name(uint64_t flags)
    {
    	static char buf[65];
    	int present;
    	size_t i, j;
    
    	for (i = 0, j = 0; i < ARRAY_SIZE(page_flag_names); i++) {
    		present = (flags >> i) & 1;
    		if (!page_flag_names[i]) {
    			if (present)
    				fatal("unknown flag bit %d\n", i);
    			continue;
    		}
    		buf[j++] = present ? page_flag_names[i][0] : '_';
    	}
    
    	return buf;
    }
    
    static char *page_flag_longname(uint64_t flags)
    {
    	static char buf[1024];
    	size_t i, n;
    
    	for (i = 0, n = 0; i < ARRAY_SIZE(page_flag_names); i++) {
    		if (!page_flag_names[i])
    			continue;
    		if ((flags >> i) & 1)
    			n += snprintf(buf + n, sizeof(buf) - n, "%s,",
    					page_flag_names[i] + 2);
    	}
    	if (n)
    		n--;
    	buf[n] = '\0';
    
    	return buf;
    }
    
    
    /*
     * page list and summary
     */
    
    static void show_page_range(unsigned long voffset, unsigned long offset,
    			    unsigned long size, uint64_t flags,
    			    uint64_t cgroup, uint64_t mapcnt)
    {
    	static uint64_t      flags0;
    	static uint64_t	     cgroup0;
    	static uint64_t      mapcnt0;
    	static unsigned long voff;
    	static unsigned long index;
    	static unsigned long count;
    
    	if (flags == flags0 && cgroup == cgroup0 && mapcnt == mapcnt0 &&
    	    offset == index + count && size && voffset == voff + count) {
    		count += size;
    		return;
    	}
    
    	if (count) {
    		if (opt_pid)
    			printf("%lx\t", voff);
    		if (opt_file)
    			printf("%lu\t", voff);
    		if (opt_list_cgroup)
    			printf("@%llu\t", (unsigned long long)cgroup0);
    		if (opt_list_mapcnt)
    			printf("%lu\t", mapcnt0);
    		printf("%lx\t%lx\t%s\n",
    				index, count, page_flag_name(flags0));
    	}
    
    	flags0 = flags;
    	cgroup0 = cgroup;
    	mapcnt0 = mapcnt;
    	index  = offset;
    	voff   = voffset;
    	count  = size;
    }
    
    static void flush_page_range(void)
    {
    	show_page_range(0, 0, 0, 0, 0, 0);
    }
    
    static void show_page(unsigned long voffset, unsigned long offset,
    		      uint64_t flags, uint64_t cgroup, uint64_t mapcnt)
    {
    	if (opt_pid)
    		printf("%lx\t", voffset);
    	if (opt_file)
    		printf("%lu\t", voffset);
    	if (opt_list_cgroup)
    		printf("@%llu\t", (unsigned long long)cgroup);
    	if (opt_list_mapcnt)
    		printf("%lu\t", mapcnt);
    
    	printf("%lx\t%s\n", offset, page_flag_name(flags));
    }
    
    static void show_summary(void)
    {
    	size_t i;
    
    	printf("             flags\tpage-count       MB"
    		"  symbolic-flags\t\t\tlong-symbolic-flags\n");
    
    	for (i = 0; i < ARRAY_SIZE(nr_pages); i++) {
    		if (nr_pages[i])
    			printf("0x%016llx\t%10lu %8lu  %s\t%s\n",
    				(unsigned long long)page_flags[i],
    				nr_pages[i],
    				pages2mb(nr_pages[i]),
    				page_flag_name(page_flags[i]),
    				page_flag_longname(page_flags[i]));
    	}
    
    	printf("             total\t%10lu %8lu\n",
    			total_pages, pages2mb(total_pages));
    }
    
    
    /*
     * page flag filters
     */
    
    static int bit_mask_ok(uint64_t flags)
    {
    	int i;
    
    	for (i = 0; i < nr_bit_filters; i++) {
    		if (opt_bits[i] == KPF_ALL_BITS) {
    			if ((flags & opt_mask[i]) == 0)
    				return 0;
    		} else {
    			if ((flags & opt_mask[i]) != opt_bits[i])
    				return 0;
    		}
    	}
    
    	return 1;
    }
    
    static uint64_t expand_overloaded_flags(uint64_t flags, uint64_t pme)
    {
    	/* SLOB/SLUB overload several page flags */
    	if (flags & BIT(SLAB)) {
    		if (flags & BIT(PRIVATE))
    			flags ^= BIT(PRIVATE) | BIT(SLOB_FREE);
    		if (flags & BIT(ACTIVE))
    			flags ^= BIT(ACTIVE) | BIT(SLUB_FROZEN);
    		if (flags & BIT(ERROR))
    			flags ^= BIT(ERROR) | BIT(SLUB_DEBUG);
    	}
    
    	/* PG_reclaim is overloaded as PG_readahead in the read path */
    	if ((flags & (BIT(RECLAIM) | BIT(WRITEBACK))) == BIT(RECLAIM))
    		flags ^= BIT(RECLAIM) | BIT(READAHEAD);
    
    	if (pme & PM_SOFT_DIRTY)
    		flags |= BIT(SOFTDIRTY);
    	if (pme & PM_FILE)
    		flags |= BIT(FILE);
    	if (pme & PM_SWAP)
    		flags |= BIT(SWAP);
    	if (pme & PM_MMAP_EXCLUSIVE)
    		flags |= BIT(MMAP_EXCLUSIVE);
    
    	return flags;
    }
    
    static uint64_t well_known_flags(uint64_t flags)
    {
    	/* hide flags intended only for kernel hacker */
    	flags &= ~KPF_HACKERS_BITS;
    
    	/* hide non-hugeTLB compound pages */
    	if ((flags & BITS_COMPOUND) && !(flags & BIT(HUGE)))
    		flags &= ~BITS_COMPOUND;
    
    	return flags;
    }
    
    static uint64_t kpageflags_flags(uint64_t flags, uint64_t pme)
    {
    	if (opt_raw)
    		flags = expand_overloaded_flags(flags, pme);
    	else
    		flags = well_known_flags(flags);
    
    	return flags;
    }
    
    /*
     * page actions
     */
    
    static void prepare_hwpoison_fd(void)
    {
    	char buf[MAX_PATH + 1];
    
    	hwpoison_debug_fs = debugfs__mount();
    	if (!hwpoison_debug_fs) {
    		perror("mount debugfs");
    		exit(EXIT_FAILURE);
    	}
    
    	if (opt_hwpoison && !hwpoison_inject_fd) {
    		snprintf(buf, MAX_PATH, "%s/hwpoison/corrupt-pfn",
    			hwpoison_debug_fs);
    		hwpoison_inject_fd = checked_open(buf, O_WRONLY);
    	}
    
    	if (opt_unpoison && !hwpoison_forget_fd) {
    		snprintf(buf, MAX_PATH, "%s/hwpoison/unpoison-pfn",
    			hwpoison_debug_fs);
    		hwpoison_forget_fd = checked_open(buf, O_WRONLY);
    	}
    }
    
    static int hwpoison_page(unsigned long offset)
    {
    	char buf[100];
    	int len;
    
    	len = sprintf(buf, "0x%lx\n", offset);
    	len = write(hwpoison_inject_fd, buf, len);
    	if (len < 0) {
    		perror("hwpoison inject");
    		return len;
    	}
    	return 0;
    }
    
    static int unpoison_page(unsigned long offset)
    {
    	char buf[100];
    	int len;
    
    	len = sprintf(buf, "0x%lx\n", offset);
    	len = write(hwpoison_forget_fd, buf, len);
    	if (len < 0) {
    		perror("hwpoison forget");
    		return len;
    	}
    	return 0;
    }
    
    static int mark_page_idle(unsigned long offset)
    {
    	static unsigned long off;
    	static uint64_t buf;
    	int len;
    
    	if ((offset / 64 == off / 64) || buf == 0) {
    		buf |= 1UL << (offset % 64);
    		off = offset;
    		return 0;
    	}
    
    	len = pwrite(page_idle_fd, &buf, 8, 8 * (off / 64));
    	if (len < 0) {
    		perror("mark page idle");
    		return len;
    	}
    
    	buf = 1UL << (offset % 64);
    	off = offset;
    
    	return 0;
    }
    
    /*
     * page frame walker
     */
    
    static size_t hash_slot(uint64_t flags)
    {
    	size_t k = HASH_KEY(flags);
    	size_t i;
    
    	/* Explicitly reserve slot 0 for flags 0: the following logic
    	 * cannot distinguish an unoccupied slot from slot (flags==0).
    	 */
    	if (flags == 0)
    		return 0;
    
    	/* search through the remaining (HASH_SIZE-1) slots */
    	for (i = 1; i < ARRAY_SIZE(page_flags); i++, k++) {
    		if (!k || k >= ARRAY_SIZE(page_flags))
    			k = 1;
    		if (page_flags[k] == 0) {
    			page_flags[k] = flags;
    			return k;
    		}
    		if (page_flags[k] == flags)
    			return k;
    	}
    
    	fatal("hash table full: bump up HASH_SHIFT?\n");
    	exit(EXIT_FAILURE);
    }
    
    static void add_page(unsigned long voffset, unsigned long offset,
    		     uint64_t flags, uint64_t cgroup, uint64_t mapcnt,
    		     uint64_t pme)
    {
    	flags = kpageflags_flags(flags, pme);
    
    	if (!bit_mask_ok(flags))
    		return;
    
    	if (opt_cgroup && cgroup != (uint64_t)opt_cgroup)
    		return;
    
    	if (opt_hwpoison)
    		hwpoison_page(offset);
    	if (opt_unpoison)
    		unpoison_page(offset);
    
    	if (opt_mark_idle)
    		mark_page_idle(offset);
    
    	if (opt_list == 1)
    		show_page_range(voffset, offset, 1, flags, cgroup, mapcnt);
    	else if (opt_list == 2)
    		show_page(voffset, offset, flags, cgroup, mapcnt);
    
    	nr_pages[hash_slot(flags)]++;
    	total_pages++;
    }
    
    #define KPAGEFLAGS_BATCH	(64 << 10)	/* 64k pages */
    static void walk_pfn(unsigned long voffset,
    		     unsigned long index,
    		     unsigned long count,
    		     uint64_t pme)
    {
    	uint64_t buf[KPAGEFLAGS_BATCH];
    	uint64_t cgi[KPAGEFLAGS_BATCH];
    	uint64_t cnt[KPAGEFLAGS_BATCH];
    	unsigned long batch;
    	unsigned long pages;
    	unsigned long i;
    
    	/*
    	 * kpagecgroup_read() reads only if kpagecgroup were opened, but
    	 * /proc/kpagecgroup might even not exist, so it's better to fill
    	 * them with zeros here.
    	 */
    	if (count == 1)
    		cgi[0] = 0;
    	else
    		memset(cgi, 0, sizeof cgi);
    
    	while (count) {
    		batch = min_t(unsigned long, count, KPAGEFLAGS_BATCH);
    		pages = kpageflags_read(buf, index, batch);
    		if (pages == 0)
    			break;
    
    		if (kpagecgroup_read(cgi, index, pages) != pages)
    			fatal("kpagecgroup returned fewer pages than expected");
    
    		if (kpagecount_read(cnt, index, batch) != pages)
    			fatal("kpagecount returned fewer pages than expected");
    
    		for (i = 0; i < pages; i++)
    			add_page(voffset + i, index + i,
    				 buf[i], cgi[i], cnt[i], pme);
    
    		index += pages;
    		count -= pages;
    	}
    }
    
    static void walk_swap(unsigned long voffset, uint64_t pme)
    {
    	uint64_t flags = kpageflags_flags(0, pme);
    
    	if (!bit_mask_ok(flags))
    		return;
    
    	if (opt_cgroup)
    		return;
    
    	if (opt_list == 1)
    		show_page_range(voffset, pagemap_swap_offset(pme),
    				1, flags, 0, 0);
    	else if (opt_list == 2)
    		show_page(voffset, pagemap_swap_offset(pme), flags, 0, 0);
    
    	nr_pages[hash_slot(flags)]++;
    	total_pages++;
    }
    
    #define PAGEMAP_BATCH	(64 << 10)
    static void walk_vma(unsigned long index, unsigned long count)
    {
    	uint64_t buf[PAGEMAP_BATCH];
    	unsigned long batch;
    	unsigned long pages;
    	unsigned long pfn;
    	unsigned long i;
    
    	while (count) {
    		batch = min_t(unsigned long, count, PAGEMAP_BATCH);
    		pages = pagemap_read(buf, index, batch);
    		if (pages == 0)
    			break;
    
    		for (i = 0; i < pages; i++) {
    			pfn = pagemap_pfn(buf[i]);
    			if (pfn)
    				walk_pfn(index + i, pfn, 1, buf[i]);
    			if (buf[i] & PM_SWAP)
    				walk_swap(index + i, buf[i]);
    		}
    
    		index += pages;
    		count -= pages;
    	}
    }
    
    static void walk_task(unsigned long index, unsigned long count)
    {
    	const unsigned long end = index + count;
    	unsigned long start;
    	int i = 0;
    
    	while (index < end) {
    
    		while (pg_end[i] <= index)
    			if (++i >= nr_vmas)
    				return;
    		if (pg_start[i] >= end)
    			return;
    
    		start = max_t(unsigned long, pg_start[i], index);
    		index = min_t(unsigned long, pg_end[i], end);
    
    		assert(start < index);
    		walk_vma(start, index - start);
    	}
    }
    
    static void add_addr_range(unsigned long offset, unsigned long size)
    {
    	if (nr_addr_ranges >= MAX_ADDR_RANGES)
    		fatal("too many addr ranges\n");
    
    	opt_offset[nr_addr_ranges] = offset;
    	opt_size[nr_addr_ranges] = min_t(unsigned long, size, ULONG_MAX-offset);
    	nr_addr_ranges++;
    }
    
    static void walk_addr_ranges(void)
    {
    	int i;
    
    	kpageflags_fd = checked_open(opt_kpageflags, O_RDONLY);
    
    	if (!nr_addr_ranges)
    		add_addr_range(0, ULONG_MAX);
    
    	for (i = 0; i < nr_addr_ranges; i++)
    		if (!opt_pid)
    			walk_pfn(opt_offset[i], opt_offset[i], opt_size[i], 0);
    		else
    			walk_task(opt_offset[i], opt_size[i]);
    
    	if (opt_mark_idle)
    		mark_page_idle(0);
    
    	close(kpageflags_fd);
    }
    
    
    /*
     * user interface
     */
    
    static const char *page_flag_type(uint64_t flag)
    {
    	if (flag & KPF_HACKERS_BITS)
    		return "(r)";
    	if (flag & KPF_OVERLOADED_BITS)
    		return "(o)";
    	return "   ";
    }
    
    static void usage(void)
    {
    	size_t i, j;
    
    	printf(
    "page-types [options]\n"
    "            -r|--raw                   Raw mode, for kernel developers\n"
    "            -d|--describe flags        Describe flags\n"
    "            -a|--addr    addr-spec     Walk a range of pages\n"
    "            -b|--bits    bits-spec     Walk pages with specified bits\n"
    "            -c|--cgroup  path|@inode   Walk pages within memory cgroup\n"
    "            -p|--pid     pid           Walk process address space\n"
    "            -f|--file    filename      Walk file address space\n"
    "            -i|--mark-idle             Mark pages idle\n"
    "            -l|--list                  Show page details in ranges\n"
    "            -L|--list-each             Show page details one by one\n"
    "            -C|--list-cgroup           Show cgroup inode for pages\n"
    "            -M|--list-mapcnt           Show page map count\n"
    "            -N|--no-summary            Don't show summary info\n"
    "            -X|--hwpoison              hwpoison pages\n"
    "            -x|--unpoison              unpoison pages\n"
    "            -F|--kpageflags filename   kpageflags file to parse\n"
    "            -h|--help                  Show this usage message\n"
    "flags:\n"
    "            0x10                       bitfield format, e.g.\n"
    "            anon                       bit-name, e.g.\n"
    "            0x10,anon                  comma-separated list, e.g.\n"
    "addr-spec:\n"
    "            N                          one page at offset N (unit: pages)\n"
    "            N+M                        pages range from N to N+M-1\n"
    "            N,M                        pages range from N to M-1\n"
    "            N,                         pages range from N to end\n"
    "            ,M                         pages range from 0 to M-1\n"
    "bits-spec:\n"
    "            bit1,bit2                  (flags & (bit1|bit2)) != 0\n"
    "            bit1,bit2=bit1             (flags & (bit1|bit2)) == bit1\n"
    "            bit1,~bit2                 (flags & (bit1|bit2)) == bit1\n"
    "            =bit1,bit2                 flags == (bit1|bit2)\n"
    "bit-names:\n"
    	);
    
    	for (i = 0, j = 0; i < ARRAY_SIZE(page_flag_names); i++) {
    		if (!page_flag_names[i])
    			continue;
    		printf("%16s%s", page_flag_names[i] + 2,
    				 page_flag_type(1ULL << i));
    		if (++j > 3) {
    			j = 0;
    			putchar('\n');
    		}
    	}
    	printf("\n                                   "
    		"(r) raw mode bits  (o) overloaded bits\n");
    }
    
    static unsigned long long parse_number(const char *str)
    {
    	unsigned long long n;
    
    	n = strtoll(str, NULL, 0);
    
    	if (n == 0 && str[0] != '0')
    		fatal("invalid name or number: %s\n", str);
    
    	return n;
    }
    
    static void parse_pid(const char *str)
    {
    	FILE *file;
    	char buf[5000];
    
    	opt_pid = parse_number(str);
    
    	sprintf(buf, "/proc/%d/pagemap", opt_pid);
    	pagemap_fd = checked_open(buf, O_RDONLY);
    
    	sprintf(buf, "/proc/%d/maps", opt_pid);
    	file = fopen(buf, "r");
    	if (!file) {
    		perror(buf);
    		exit(EXIT_FAILURE);
    	}
    
    	while (fgets(buf, sizeof(buf), file) != NULL) {
    		unsigned long vm_start;
    		unsigned long vm_end;
    		unsigned long long pgoff;
    		int major, minor;
    		char r, w, x, s;
    		unsigned long ino;
    		int n;
    
    		n = sscanf(buf, "%lx-%lx %c%c%c%c %llx %x:%x %lu",
    			   &vm_start,
    			   &vm_end,
    			   &r, &w, &x, &s,
    			   &pgoff,
    			   &major, &minor,
    			   &ino);
    		if (n < 10) {
    			fprintf(stderr, "unexpected line: %s\n", buf);
    			continue;
    		}
    		pg_start[nr_vmas] = vm_start / page_size;
    		pg_end[nr_vmas] = vm_end / page_size;
    		if (++nr_vmas >= MAX_VMAS) {
    			fprintf(stderr, "too many VMAs\n");
    			break;
    		}
    	}
    	fclose(file);
    }
    
    static void show_file(const char *name, const struct stat *st)
    {
    	unsigned long long size = st->st_size;
    	char atime[64], mtime[64];
    	long now = time(NULL);
    
    	printf("%s\tInode: %u\tSize: %llu (%llu pages)\n",
    			name, (unsigned)st->st_ino,
    			size, (size + page_size - 1) / page_size);
    
    	strftime(atime, sizeof(atime), "%c", localtime(&st->st_atime));
    	strftime(mtime, sizeof(mtime), "%c", localtime(&st->st_mtime));
    
    	printf("Modify: %s (%ld seconds ago)\nAccess: %s (%ld seconds ago)\n",
    			mtime, now - st->st_mtime,
    			atime, now - st->st_atime);
    }
    
    static sigjmp_buf sigbus_jmp;
    
    static void * volatile sigbus_addr;
    
    static void sigbus_handler(int sig, siginfo_t *info, void *ucontex)
    {
    	(void)sig;
    	(void)ucontex;
    	sigbus_addr = info ? info->si_addr : NULL;
    	siglongjmp(sigbus_jmp, 1);
    }
    
    static struct sigaction sigbus_action = {
    	.sa_sigaction = sigbus_handler,
    	.sa_flags = SA_SIGINFO,
    };
    
    static void walk_file(const char *name, const struct stat *st)
    {
    	uint8_t vec[PAGEMAP_BATCH];
    	uint64_t buf[PAGEMAP_BATCH], flags;
    	uint64_t cgroup = 0;
    	uint64_t mapcnt = 0;
    	unsigned long nr_pages, pfn, i;
    	off_t off, end = st->st_size;
    	int fd;
    	ssize_t len;
    	void *ptr;
    	int first = 1;
    
    	fd = checked_open(name, O_RDONLY|O_NOATIME|O_NOFOLLOW);
    
    	for (off = 0; off < end; off += len) {
    		nr_pages = (end - off + page_size - 1) / page_size;
    		if (nr_pages > PAGEMAP_BATCH)
    			nr_pages = PAGEMAP_BATCH;
    		len = nr_pages * page_size;
    
    		ptr = mmap(NULL, len, PROT_READ, MAP_SHARED, fd, off);
    		if (ptr == MAP_FAILED)
    			fatal("mmap failed: %s", name);
    
    		/* determine cached pages */
    		if (mincore(ptr, len, vec))
    			fatal("mincore failed: %s", name);
    
    		/* turn off readahead */
    		if (madvise(ptr, len, MADV_RANDOM))
    			fatal("madvice failed: %s", name);
    
    		if (sigsetjmp(sigbus_jmp, 1)) {
    			end = off + sigbus_addr ? sigbus_addr - ptr : 0;
    			fprintf(stderr, "got sigbus at offset %lld: %s\n",
    					(long long)end, name);
    			goto got_sigbus;
    		}
    
    		/* populate ptes */
    		for (i = 0; i < nr_pages ; i++) {
    			if (vec[i] & 1)
    				(void)*(volatile int *)(ptr + i * page_size);
    		}
    got_sigbus:
    
    		/* turn off harvesting reference bits */
    		if (madvise(ptr, len, MADV_SEQUENTIAL))
    			fatal("madvice failed: %s", name);
    
    		if (pagemap_read(buf, (unsigned long)ptr / page_size,
    					nr_pages) != nr_pages)
    			fatal("cannot read pagemap");
    
    		munmap(ptr, len);
    
    		for (i = 0; i < nr_pages; i++) {
    			pfn = pagemap_pfn(buf[i]);
    			if (!pfn)
    				continue;
    			if (!kpageflags_read(&flags, pfn, 1))
    				continue;
    			if (!kpagecgroup_read(&cgroup, pfn, 1))
    				fatal("kpagecgroup_read failed");
    			if (!kpagecount_read(&mapcnt, pfn, 1))
    				fatal("kpagecount_read failed");
    			if (first && opt_list) {
    				first = 0;
    				flush_page_range();
    				show_file(name, st);
    			}
    			add_page(off / page_size + i, pfn,
    				 flags, cgroup, mapcnt, buf[i]);
    		}
    	}
    
    	close(fd);
    }
    
    int walk_tree(const char *name, const struct stat *st, int type, struct FTW *f)
    {
    	(void)f;
    	switch (type) {
    	case FTW_F:
    		if (S_ISREG(st->st_mode))
    			walk_file(name, st);
    		break;
    	case FTW_DNR:
    		fprintf(stderr, "cannot read dir: %s\n", name);
    		break;
    	}
    	return 0;
    }
    
    static void walk_page_cache(void)
    {
    	struct stat st;
    
    	kpageflags_fd = checked_open(opt_kpageflags, O_RDONLY);
    	pagemap_fd = checked_open("/proc/self/pagemap", O_RDONLY);
    	sigaction(SIGBUS, &sigbus_action, NULL);
    
    	if (stat(opt_file, &st))
    		fatal("stat failed: %s\n", opt_file);
    
    	if (S_ISREG(st.st_mode)) {
    		walk_file(opt_file, &st);
    	} else if (S_ISDIR(st.st_mode)) {
    		/* do not follow symlinks and mountpoints */
    		if (nftw(opt_file, walk_tree, 64, FTW_MOUNT | FTW_PHYS) < 0)
    			fatal("nftw failed: %s\n", opt_file);
    	} else
    		fatal("unhandled file type: %s\n", opt_file);
    
    	close(kpageflags_fd);
    	close(pagemap_fd);
    	signal(SIGBUS, SIG_DFL);
    }
    
    static void parse_file(const char *name)
    {
    	opt_file = name;
    }
    
    static void parse_cgroup(const char *path)
    {
    	if (path[0] == '@') {
    		opt_cgroup = parse_number(path + 1);
    		return;
    	}
    
    	struct stat st;
    
    	if (stat(path, &st))
    		fatal("stat failed: %s: %m\n", path);
    
    	if (!S_ISDIR(st.st_mode))
    		fatal("cgroup supposed to be a directory: %s\n", path);
    
    	opt_cgroup = st.st_ino;
    }
    
    static void parse_addr_range(const char *optarg)
    {
    	unsigned long offset;
    	unsigned long size;
    	char *p;
    
    	p = strchr(optarg, ',');
    	if (!p)
    		p = strchr(optarg, '+');
    
    	if (p == optarg) {
    		offset = 0;
    		size   = parse_number(p + 1);
    	} else if (p) {
    		offset = parse_number(optarg);
    		if (p[1] == '\0')
    			size = ULONG_MAX;
    		else {
    			size = parse_number(p + 1);
    			if (*p == ',') {
    				if (size < offset)
    					fatal("invalid range: %lu,%lu\n",
    							offset, size);
    				size -= offset;
    			}
    		}
    	} else {
    		offset = parse_number(optarg);
    		size   = 1;
    	}
    
    	add_addr_range(offset, size);
    }
    
    static void add_bits_filter(uint64_t mask, uint64_t bits)
    {
    	if (nr_bit_filters >= MAX_BIT_FILTERS)
    		fatal("too much bit filters\n");
    
    	opt_mask[nr_bit_filters] = mask;
    	opt_bits[nr_bit_filters] = bits;
    	nr_bit_filters++;
    }
    
    static uint64_t parse_flag_name(const char *str, int len)
    {
    	size_t i;
    
    	if (!*str || !len)
    		return 0;
    
    	if (len <= 8 && !strncmp(str, "compound", len))
    		return BITS_COMPOUND;
    
    	for (i = 0; i < ARRAY_SIZE(page_flag_names); i++) {
    		if (!page_flag_names[i])
    			continue;
    		if (!strncmp(str, page_flag_names[i] + 2, len))
    			return 1ULL << i;
    	}
    
    	return parse_number(str);
    }
    
    static uint64_t parse_flag_names(const char *str, int all)
    {
    	const char *p    = str;
    	uint64_t   flags = 0;
    
    	while (1) {
    		if (*p == ',' || *p == '=' || *p == '\0') {
    			if ((*str != '~') || (*str == '~' && all && *++str))
    				flags |= parse_flag_name(str, p - str);
    			if (*p != ',')
    				break;
    			str = p + 1;
    		}
    		p++;
    	}
    
    	return flags;
    }
    
    static void parse_bits_mask(const char *optarg)
    {
    	uint64_t mask;
    	uint64_t bits;
    	const char *p;
    
    	p = strchr(optarg, '=');
    	if (p == optarg) {
    		mask = KPF_ALL_BITS;
    		bits = parse_flag_names(p + 1, 0);
    	} else if (p) {
    		mask = parse_flag_names(optarg, 0);
    		bits = parse_flag_names(p + 1, 0);
    	} else if (strchr(optarg, '~')) {
    		mask = parse_flag_names(optarg, 1);
    		bits = parse_flag_names(optarg, 0);
    	} else {
    		mask = parse_flag_names(optarg, 0);
    		bits = KPF_ALL_BITS;
    	}
    
    	add_bits_filter(mask, bits);
    }
    
    static void parse_kpageflags(const char *name)
    {
    	opt_kpageflags = name;
    }
    
    static void describe_flags(const char *optarg)
    {
    	uint64_t flags = parse_flag_names(optarg, 0);
    
    	printf("0x%016llx\t%s\t%s\n",
    		(unsigned long long)flags,
    		page_flag_name(flags),
    		page_flag_longname(flags));
    }
    
    static const struct option opts[] = {
    	{ "raw"       , 0, NULL, 'r' },
    	{ "pid"       , 1, NULL, 'p' },
    	{ "file"      , 1, NULL, 'f' },
    	{ "addr"      , 1, NULL, 'a' },
    	{ "bits"      , 1, NULL, 'b' },
    	{ "cgroup"    , 1, NULL, 'c' },
    	{ "describe"  , 1, NULL, 'd' },
    	{ "mark-idle" , 0, NULL, 'i' },
    	{ "list"      , 0, NULL, 'l' },
    	{ "list-each" , 0, NULL, 'L' },
    	{ "list-cgroup", 0, NULL, 'C' },
    	{ "list-mapcnt", 0, NULL, 'M' },
    	{ "no-summary", 0, NULL, 'N' },
    	{ "hwpoison"  , 0, NULL, 'X' },
    	{ "unpoison"  , 0, NULL, 'x' },
    	{ "kpageflags", 0, NULL, 'F' },
    	{ "help"      , 0, NULL, 'h' },
    	{ NULL        , 0, NULL, 0 }
    };
    
    int main(int argc, char *argv[])
    {
    	int c;
    
    	page_size = getpagesize();
    
    	while ((c = getopt_long(argc, argv,
    				"rp:f:a:b:d:c:CilLMNXxF:h",
    				opts, NULL)) != -1) {
    		switch (c) {
    		case 'r':
    			opt_raw = 1;
    			break;
    		case 'p':
    			parse_pid(optarg);
    			break;
    		case 'f':
    			parse_file(optarg);
    			break;
    		case 'a':
    			parse_addr_range(optarg);
    			break;
    		case 'b':
    			parse_bits_mask(optarg);
    			break;
    		case 'c':
    			parse_cgroup(optarg);
    			break;
    		case 'C':
    			opt_list_cgroup = 1;
    			break;
    		case 'd':
    			describe_flags(optarg);
    			exit(0);
    		case 'i':
    			opt_mark_idle = 1;
    			break;
    		case 'l':
    			opt_list = 1;
    			break;
    		case 'L':
    			opt_list = 2;
    			break;
    		case 'M':
    			opt_list_mapcnt = 1;
    			break;
    		case 'N':
    			opt_no_summary = 1;
    			break;
    		case 'X':
    			opt_hwpoison = 1;
    			prepare_hwpoison_fd();
    			break;
    		case 'x':
    			opt_unpoison = 1;
    			prepare_hwpoison_fd();
    			break;
    		case 'F':
    			parse_kpageflags(optarg);
    			break;
    		case 'h':
    			usage();
    			exit(0);
    		default:
    			usage();
    			exit(1);
    		}
    	}
    
    	if (!opt_kpageflags)
    		opt_kpageflags = PROC_KPAGEFLAGS;
    
    	if (opt_cgroup || opt_list_cgroup)
    		kpagecgroup_fd = checked_open(PROC_KPAGECGROUP, O_RDONLY);
    
    	if (opt_list && opt_list_mapcnt)
    		kpagecount_fd = checked_open(PROC_KPAGECOUNT, O_RDONLY);
    
    	if (opt_mark_idle && opt_file)
    		page_idle_fd = checked_open(SYS_KERNEL_MM_PAGE_IDLE, O_RDWR);
    
    	if (opt_list && opt_pid)
    		printf("voffset\t");
    	if (opt_list && opt_file)
    		printf("foffset\t");
    	if (opt_list && opt_list_cgroup)
    		printf("cgroup\t");
    	if (opt_list && opt_list_mapcnt)
    		printf("map-cnt\t");
    
    	if (opt_list == 1)
    		printf("offset\tlen\tflags\n");
    	if (opt_list == 2)
    		printf("offset\tflags\n");
    
    	if (opt_file)
    		walk_page_cache();
    	else
    		walk_addr_ranges();
    
    	if (opt_list == 1)
    		flush_page_range();
    
    	if (opt_no_summary)
    		return 0;
    
    	if (opt_list)
    		printf("\n\n");
    
    	show_summary();
    
    	if (opt_list_mapcnt)
    		close(kpagecount_fd);
    
    	if (page_idle_fd >= 0)
    		close(page_idle_fd);
    
    	return 0;
    }