[CRIU] [PATCH] Punch holes in input files when restoring anonymous non-shared memory if --auto-dedup is enabled.
Pawel Stradomski
pstradomski at google.com
Tue Jul 24 13:12:27 MSK 2018
This reduces memory usage if image files are stored on tmpfs.
Signed-off-by: Pawel Stradomski <pstradomski at google.com>
---
.../arch/arm/plugins/std/syscalls/syscall.def | 1 +
.../plugins/std/syscalls/syscall-ppc64.tbl | 1 +
.../plugins/std/syscalls/syscall-s390.tbl | 1 +
.../x86/plugins/std/syscalls/syscall_32.tbl | 1 +
.../x86/plugins/std/syscalls/syscall_64.tbl | 1 +
criu/mem.c | 16 +++++++++-
criu/pie/restorer.c | 31 +++++++++++++++++++
7 files changed, 51 insertions(+), 1 deletion(-)
diff --git a/compel/arch/arm/plugins/std/syscalls/syscall.def b/compel/arch/arm/plugins/std/syscalls/syscall.def
index b68f9f2f..bcd61d4a 100644
--- a/compel/arch/arm/plugins/std/syscalls/syscall.def
+++ b/compel/arch/arm/plugins/std/syscalls/syscall.def
@@ -109,3 +109,4 @@ seccomp 277 383 (unsigned int op, unsigned int flags, const char *uargs)
gettimeofday 169 78 (struct timeval *tv, struct timezone *tz)
preadv_raw 69 361 (int fd, struct iovec *iov, unsigned long nr, unsigned long pos_l, unsigned long pos_h)
userfaultfd 282 388 (int flags)
+fallocate 47 352 (int fd, int mode, loff_t offset, loff_t len)
diff --git a/compel/arch/ppc64/plugins/std/syscalls/syscall-ppc64.tbl b/compel/arch/ppc64/plugins/std/syscalls/syscall-ppc64.tbl
index fa0b034e..62e0bc1a 100644
--- a/compel/arch/ppc64/plugins/std/syscalls/syscall-ppc64.tbl
+++ b/compel/arch/ppc64/plugins/std/syscalls/syscall-ppc64.tbl
@@ -89,6 +89,7 @@ __NR_set_robust_list 300 sys_set_robust_list (struct robust_list_head *head, si
__NR_get_robust_list 299 sys_get_robust_list (int pid, struct robust_list_head **head_ptr, size_t *len_ptr)
__NR_vmsplice 285 sys_vmsplice (int fd, const struct iovec *iov, unsigned long nr_segs, unsigned int flags)
__NR_openat 286 sys_openat (int dfd, const char *filename, int flags, int mode)
+__NR_fallocate 309 sys_fallocate (int fd, int mode, loff_t offset, loff_t len)
__NR_timerfd_settime 311 sys_timerfd_settime (int ufd, int flags, const struct itimerspec *utmr, struct itimerspec *otmr)
__NR_signalfd4 313 sys_signalfd (int fd, k_rtsigset_t *mask, size_t sizemask, int flags)
__NR_rt_tgsigqueueinfo 322 sys_rt_tgsigqueueinfo (pid_t tgid, pid_t pid, int sig, siginfo_t *info)
diff --git a/compel/arch/s390/plugins/std/syscalls/syscall-s390.tbl b/compel/arch/s390/plugins/std/syscalls/syscall-s390.tbl
index bc77ae97..3521e915 100644
--- a/compel/arch/s390/plugins/std/syscalls/syscall-s390.tbl
+++ b/compel/arch/s390/plugins/std/syscalls/syscall-s390.tbl
@@ -89,6 +89,7 @@ __NR_set_robust_list 304 sys_set_robust_list (struct robust_list_head *head, si
__NR_get_robust_list 305 sys_get_robust_list (int pid, struct robust_list_head **head_ptr, size_t *len_ptr)
__NR_vmsplice 309 sys_vmsplice (int fd, const struct iovec *iov, unsigned long nr_segs, unsigned int flags)
__NR_openat 288 sys_openat (int dfd, const char *filename, int flags, int mode)
+__NR_fallocate 314 sys_fallocate (int fd, int mode, loff_t offset, loff_t len)
__NR_timerfd_settime 320 sys_timerfd_settime (int ufd, int flags, const struct itimerspec *utmr, struct itimerspec *otmr)
__NR_signalfd4 322 sys_signalfd (int fd, k_rtsigset_t *mask, size_t sizemask, int flags)
__NR_rt_tgsigqueueinfo 330 sys_rt_tgsigqueueinfo (pid_t tgid, pid_t pid, int sig, siginfo_t *info)
diff --git a/compel/arch/x86/plugins/std/syscalls/syscall_32.tbl b/compel/arch/x86/plugins/std/syscalls/syscall_32.tbl
index 9e1de281..a6c55b83 100644
--- a/compel/arch/x86/plugins/std/syscalls/syscall_32.tbl
+++ b/compel/arch/x86/plugins/std/syscalls/syscall_32.tbl
@@ -83,6 +83,7 @@ __NR_set_robust_list 311 sys_set_robust_list (struct robust_list_head *head, si
__NR_get_robust_list 312 sys_get_robust_list (int pid, struct robust_list_head **head_ptr, size_t *len_ptr)
__NR_vmsplice 316 sys_vmsplice (int fd, const struct iovec *iov, unsigned int nr_segs, unsigned int flags)
__NR_signalfd 321 sys_signalfd (int ufd, const k_rtsigset_t *sigmask, size_t sigsetsize)
+__NR_fallocate 324 sys_fallocate (int fd, int mode, loff_t offset, loff_t len)
__NR_timerfd_settime 325 sys_timerfd_settime (int ufd, int flags, const struct itimerspec *utmr, struct itimerspec *otmr)
__NR_preadv 333 sys_preadv_raw (int fd, struct iovec *iov, unsigned long nr, unsigned long pos_l, unsigned long pos_h)
__NR_rt_tgsigqueueinfo 335 sys_rt_tgsigqueueinfo (pid_t tgid, pid_t pid, int sig, siginfo_t *uinfo)
diff --git a/compel/arch/x86/plugins/std/syscalls/syscall_64.tbl b/compel/arch/x86/plugins/std/syscalls/syscall_64.tbl
index 726fa797..64271514 100644
--- a/compel/arch/x86/plugins/std/syscalls/syscall_64.tbl
+++ b/compel/arch/x86/plugins/std/syscalls/syscall_64.tbl
@@ -94,6 +94,7 @@ __NR_set_robust_list 273 sys_set_robust_list (struct robust_list_head *head, s
__NR_get_robust_list 274 sys_get_robust_list (int pid, struct robust_list_head **head_ptr, size_t *len_ptr)
__NR_seccomp 317 sys_seccomp (unsigned int op, unsigned int flags, const char *uargs)
__NR_vmsplice 278 sys_vmsplice (int fd, const struct iovec *iov, unsigned long nr_segs, unsigned int flags)
+__NR_fallocate 285 sys_fallocate (int fd, int mode, loff_t offset, loff_t len)
__NR_timerfd_settime 286 sys_timerfd_settime (int ufd, int flags, const struct itimerspec *utmr, struct itimerspec *otmr)
__NR_signalfd4 289 sys_signalfd (int fd, k_rtsigset_t *mask, size_t sizemask, int flags)
__NR_preadv 295 sys_preadv_raw (int fd, struct iovec *iov, unsigned long nr, unsigned long pos_l, unsigned long pos_h)
diff --git a/criu/mem.c b/criu/mem.c
index d020b7fd..9e2375f8 100644
--- a/criu/mem.c
+++ b/criu/mem.c
@@ -1271,7 +1271,21 @@ static int prepare_vma_ios(struct pstree_item *t, struct task_restore_args *ta)
{
struct cr_img *pages;
- pages = open_image(CR_FD_PAGES, O_RSTR, rsti(t)->pages_img_id);
+ /* if auto-dedup is on we need RDWR mode to be able to punch holes
+ * in the input files (in restorer.c)
+ */
+ pages = open_image(CR_FD_PAGES, opts.auto_dedup ? O_RDWR : O_RSTR,
+ rsti(t)->pages_img_id);
+ /* When running inside namespace we might lack privileges to open the file
+ * for writing.
+ * TODO: use userns_call to do the opening instead of downgrading to opening
+ * read-only.
+ */
+ if (!pages && opts.auto_dedup) {
+ pr_warn("Failed to open image read-write, trying read-only instead. auto-dedup won't work\n");
+ pages = open_image(CR_FD_PAGES, O_RSTR, rsti(t)->pages_img_id);
+ }
+
if (!pages)
return -1;
diff --git a/criu/pie/restorer.c b/criu/pie/restorer.c
index f990e9b7..7c70d02a 100644
--- a/criu/pie/restorer.c
+++ b/criu/pie/restorer.c
@@ -50,6 +50,15 @@
#define PR_SET_PDEATHSIG 1
#endif
+#ifndef FALLOC_FL_KEEP_SIZE
+#define FALLOC_FL_KEEP_SIZE 0x01
+#endif
+
+#ifndef FALLOC_FL_PUNCH_HOLE
+#define FALLOC_FL_PUNCH_HOLE 0x02
+#endif
+
+
#define sys_prctl_safe(opcode, val1, val2, val3) \
({ \
long __ret = sys_prctl(opcode, val1, val2, val3, 0); \
@@ -646,6 +655,14 @@ static unsigned long restore_mapping(VmaEntry *vma_entry)
!(vma_entry->status & VMA_NO_PROT_WRITE))
prot |= PROT_WRITE;
+ /* TODO: Drop MAP_LOCKED bit and restore it after reading memory.
+ *
+ * Code below tries to limit memory usage by running fallocate()
+ * after each preadv() to avoid doubling memory usage (once in
+ * image files, once in process). Unfortunately, MAP_LOCKED defeats
+ * that mechanism as it causes the process to be charged for memory
+ * immediately upon mmap, not later, upon preadv().
+ */
pr_debug("\tmmap(%"PRIx64" -> %"PRIx64", %x %x %d)\n",
vma_entry->start, vma_entry->end,
prot, flags, (int)vma_entry->fd);
@@ -1355,6 +1372,11 @@ long __export_restore_task(struct task_restore_args *args)
struct iovec *iovs = rio->iovs;
int nr = rio->nr_iovs;
ssize_t r;
+ int file_flags = sys_fcntl(args->vma_ios_fd, F_GETFL, 0);
+ if (file_flags < 0) {
+ pr_err("Can't check file flags\n");
+ file_flags = 0;
+ }
while (nr) {
pr_debug("Preadv %lx:%d... (%d iovs)\n",
@@ -1367,6 +1389,15 @@ long __export_restore_task(struct task_restore_args *args)
}
pr_debug("`- returned %ld\n", (long)r);
+ /* If the file is open for writing, then it means we should punch holes
+ * in it. */
+ if (r > 0 && (file_flags & O_RDWR)) {
+ int fr = sys_fallocate(args->vma_ios_fd, FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE,
+ rio->off, r);
+ if (fr < 0) {
+ pr_debug("Failed to punch holes with fallocate: %d\n", fr);
+ }
+ }
rio->off += r;
/* Advance the iovecs */
do {
--
2.18.0.345.g5c9ce644c3-goog
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