From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: [RFC] Payloads and transient filesystem support for user-cr Date: Wed, 02 Mar 2011 23:05:24 +0100 Message-ID: <4D6EBF24.4000601@free.fr> References: <1299101725-17603-1-git-send-email-danms@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1299101725-17603-1-git-send-email-danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Dan Smith Cc: containers-qjLDD68F18O7TbgM5vRIOg@public.gmane.org List-Id: containers.vger.kernel.org On 03/02/2011 10:35 PM, Dan Smith wrote: > This adds payload support to user-cr for stashing things in the image. > The first type of payload supported is a transient filesystem image, > for things like /dev/shm. > > When I put "/dev/shm" into args.save_fs[] (and restore_fs), I am able > to checkpoint and restart programs that are using POSIX sem_* operations > successfully. The posix semaphore use the mapped deleted hardlinked files. ... sem_open("sem.dummy_sem_open", O_CREAT | O_EXCL, 0600, 1); ... lstat("/dev/shm/sem.zaptW5", 0x7ffff086f530) = -1 ENOENT (No such file or directory) open("/dev/shm/sem.zaptW5", O_RDWR|O_CREAT|O_EXCL, 0600) = 3 write(3, "\1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 32) = 32 mmap(NULL, 32, PROT_READ|PROT_WRITE, MAP_SHARED, 3, 0) = 0x7f1dda7b3000 link("/dev/shm/sem.zaptW5", "/dev/shm/sem.dummy_sem_open") = 0 fstat(3, {st_mode=S_IFREG|0600, st_size=32, ...}) = 0 brk(0) = 0x238e000 brk(0x23af000) = 0x23af000 unlink("/dev/shm/sem.zaptW5") = 0 close(3) = 0 ... AFAIK, the current implementation do not support that, no ? How is it possible to CR programs using sem_* operations in this case ? Thanks -- Daniel