diff options
Diffstat (limited to 'Documentation/vm')
| -rw-r--r-- | Documentation/vm/page-types.c | 154 |
1 files changed, 89 insertions, 65 deletions
diff --git a/Documentation/vm/page-types.c b/Documentation/vm/page-types.c index 6bdcc0632c2..18e891a329e 100644 --- a/Documentation/vm/page-types.c +++ b/Documentation/vm/page-types.c @@ -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); } } |