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Commit 4a1b6726 authored by Wu Fengguang's avatar Wu Fengguang Committed by Linus Torvalds
Browse files

page-types: make standalone pagemap/kpageflags read routines 



Refactor the code to be more modular and easier to reuse.

Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 31bbf66e

Documentation/vm/page-types.c

+89 −65
Original line number Diff line number Diff line
@@ -161,8 +161,6 @@ static unsigned long pg_start[MAX_VMAS]; 
static unsigned long	pg_end[MAX_VMAS];

static unsigned long	voffset;



static int		pagemap_fd;



#define MAX_BIT_FILTERS	64

static int		nr_bit_filters;

static uint64_t		opt_mask[MAX_BIT_FILTERS];
@@ -170,7 +168,7 @@ static uint64_t opt_bits[MAX_BIT_FILTERS]; 


static int		page_size;



#define PAGES_BATCH	(64 << 10)	/* 64k pages */

static int		pagemap_fd;

static int		kpageflags_fd;



#define HASH_SHIFT	13
@@ -226,6 +224,62 @@ int checked_open(const char *pathname, int flags) 
	return fd;

}



/*

 * pagemap/kpageflags routines

 */



static unsigned long do_u64_read(int fd, char *name,

				 uint64_t *buf,

				 unsigned long index,

				 unsigned long count)

{

	long bytes;



	if (index > ULONG_MAX / 8)

		fatal("index overflow: %lu\n", index);



	if (lseek(fd, index * 8, SEEK_SET) < 0) {

		perror(name);

		exit(EXIT_FAILURE);

	}



	bytes = read(fd, buf, count * 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, PROC_KPAGEFLAGS, 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;

}





/*

 * page flag names
@@ -432,79 +486,53 @@ static void add_page(unsigned long offset, uint64_t flags) 
	total_pages++;

}



#define KPAGEFLAGS_BATCH	(64 << 10)	/* 64k pages */

static void walk_pfn(unsigned long index, unsigned long count)

{

	uint64_t buf[KPAGEFLAGS_BATCH];

	unsigned long batch;

	unsigned long n;

	unsigned long pages;

	unsigned long i;



	if (index > ULONG_MAX / KPF_BYTES)

		fatal("index overflow: %lu\n", index);



	lseek(kpageflags_fd, index * KPF_BYTES, SEEK_SET);



	while (count) {

		uint64_t kpageflags_buf[KPF_BYTES * PAGES_BATCH];



		batch = min_t(unsigned long, count, PAGES_BATCH);

		n = read(kpageflags_fd, kpageflags_buf, batch * KPF_BYTES);

		if (n == 0)

		batch = min_t(unsigned long, count, KPAGEFLAGS_BATCH);

		pages = kpageflags_read(buf, index, batch);

		if (pages == 0)

			break;

		if (n < 0) {

			perror(PROC_KPAGEFLAGS);

			exit(EXIT_FAILURE);

		}



		if (n % KPF_BYTES != 0)

			fatal("partial read: %lu bytes\n", n);

		n = n / KPF_BYTES;



		for (i = 0; i < n; i++)

			add_page(index + i, kpageflags_buf[i]);

		for (i = 0; i < pages; i++)

			add_page(index + i, buf[i]);



		index += batch;

		count -= batch;

		index += pages;

		count -= pages;

	}

}





#define PAGEMAP_BATCH	4096

static unsigned long task_pfn(unsigned long pgoff)

#define PAGEMAP_BATCH	(64 << 10)

static void walk_vma(unsigned long index, unsigned long count)

{

	static uint64_t buf[PAGEMAP_BATCH];

	static unsigned long start;

	static long count;

	uint64_t pfn;

	uint64_t buf[PAGEMAP_BATCH];

	unsigned long batch;

	unsigned long pages;

	unsigned long pfn;

	unsigned long i;



	if (pgoff < start || pgoff >= start + count) {

		if (lseek64(pagemap_fd,

			    (uint64_t)pgoff * PM_ENTRY_BYTES,

			    SEEK_SET) < 0) {

			perror("pagemap seek");

			exit(EXIT_FAILURE);

		}

		count = read(pagemap_fd, buf, sizeof(buf));

		if (count == 0)

			return 0;

		if (count < 0) {

			perror("pagemap read");

			exit(EXIT_FAILURE);

		}

		if (count % PM_ENTRY_BYTES) {

			fatal("pagemap read not aligned.\n");

			exit(EXIT_FAILURE);

		}

		count /= PM_ENTRY_BYTES;

		start = pgoff;

	}

	while (count) {

		batch = min_t(unsigned long, count, PAGEMAP_BATCH);

		pages = pagemap_read(buf, index, batch);

		if (pages == 0)

			break;



	pfn = buf[pgoff - start];

	if (pfn & PM_PRESENT)

		pfn = PM_PFRAME(pfn);

	else

		pfn = 0;

		for (i = 0; i < pages; i++) {

			pfn = pagemap_pfn(buf[i]);

			voffset = index + i;

			if (pfn)

				walk_pfn(pfn, 1);

		}



	return pfn;

		index += pages;

		count -= pages;

	}

}



static void walk_task(unsigned long index, unsigned long count)
@@ -524,11 +552,7 @@ static void walk_task(unsigned long index, unsigned long count) 
		index   = min_t(unsigned long, pg_end[i], end);



		assert(voffset < index);

		for (; voffset < index; voffset++) {

			unsigned long pfn = task_pfn(voffset);

			if (pfn)

				walk_pfn(pfn, 1);

		}

		walk_vma(voffset, index - voffset);

	}

}