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lazy-pages: handle zombie processes

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Restore of a zombie process does not call setup_uffd which causes
lazy-pages daemon to stuck forever waiting for (pid, uffd) pair to arrive.
Let's extend the protocol between restore and lazy-pages so that for zombie
process a (0, -1) pair will be sent instead of actual (uffd, pid).

travis-ci: success for lazy-pages: misc fixes (rev4)
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
This commit is contained in:
Mike Rapoport
2016-11-04 09:08:04 -06:00
committed by Andrei Vagin
parent 1a92e78911
commit 428226a8ac
3 changed files with 28 additions and 0 deletions
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3
criu/cr-restore.c
View File

@@ -942,6 +942,9 @@ static int restore_one_zombie(CoreEntry *core)
if (inherit_fd_fini() < 0)
return -1;
if (lazy_pages_setup_zombie())
return -1;
prctl(PR_SET_NAME, (long)(void *)core->tc->comm, 0, 0, 0);
if (task_entries != NULL) {

1
criu/include/uffd.h
View File

@@ -3,6 +3,7 @@
struct task_restore_args;
extern int setup_uffd(int pid, struct task_restore_args *task_args);
extern int lazy_pages_setup_zombie(void);
extern int prepare_lazy_pages_socket(void);
#endif /* __CR_UFFD_H_ */

24
criu/uffd.c
View File

@@ -169,6 +169,12 @@ static int send_uffd(int sendfd, int pid)
goto out;
}
/* for a zombie process pid will be -1 */
if (pid == -1) {
ret = 0;
goto out;
}
if (send_fd(fd, NULL, 0, sendfd) < 0) {
pr_perror("send_fd error:");
goto out;
@@ -202,6 +208,17 @@ static int check_for_uffd()
return 0;
}
int lazy_pages_setup_zombie(void)
{
if (!opts.lazy_pages)
return 0;
if (send_uffd(0, -1))
return -1;
return 0;
}
/* This function is used by 'criu restore --lazy-pages' */
int setup_uffd(int pid, struct task_restore_args *task_args)
{
@@ -331,6 +348,11 @@ static int ud_open(int client, struct lazy_pages_info **_lpi)
}
pr_debug("received PID: %d\n", lpi->pid);
if (lpi->pid == -1) {
lpi_fini(lpi);
return 0;
}
lpi->uffd = recv_fd(client);
if (lpi->uffd < 0) {
pr_perror("recv_fd error:");
@@ -866,6 +888,8 @@ static int prepare_uffds(int epollfd)
struct lazy_pages_info *lpi = NULL;
if (ud_open(client, &lpi))
goto close_uffd;
if (lpi == NULL)
continue;
if (epoll_add_fd(epollfd, lpi->uffd))
goto close_uffd;
}