From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757983AbZA0RPA (ORCPT ); Tue, 27 Jan 2009 12:15:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756707AbZA0RKK (ORCPT ); Tue, 27 Jan 2009 12:10:10 -0500 Received: from serrano.cc.columbia.edu ([128.59.29.6]:57956 "EHLO serrano.cc.columbia.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756701AbZA0RKE (ORCPT ); Tue, 27 Jan 2009 12:10:04 -0500 From: Oren Laadan To: Andrew Morton Cc: Linus Torvalds , containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org, Thomas Gleixner , Serge Hallyn , Dave Hansen , Ingo Molnar , "H. Peter Anvin" , Alexander Viro , Oren Laadan Subject: [RFC v13][PATCH 01/14] Create syscalls: sys_checkpoint, sys_restart Date: Tue, 27 Jan 2009 12:07:59 -0500 Message-Id: <1233076092-8660-2-git-send-email-orenl@cs.columbia.edu> X-Mailer: git-send-email 1.6.0.1 In-Reply-To: <1233076092-8660-1-git-send-email-orenl@cs.columbia.edu> References: <1233076092-8660-1-git-send-email-orenl@cs.columbia.edu> X-No-Spam-Score: Local Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Create trivial sys_checkpoint and sys_restore system calls. They will enable to checkpoint and restart an entire container, to and from a checkpoint image file descriptor. The syscalls take a file descriptor (for the image file) and flags as arguments. For sys_checkpoint the first argument identifies the target container; for sys_restart it will identify the checkpoint image. A checkpoint, much like a process coredump, dumps the state of multiple processes at once, including the state of the container. The checkpoint image is written to (and read from) the file descriptor directly from the kernel. This way the data is generated and then pushed out naturally as resources and tasks are scanned to save their state. This is the approach taken by, e.g., Zap and OpenVZ. By using a return value and not a file descriptor, we can distinguish between a return from checkpoint, a return from restart (in case of a checkpoint that includes self, i.e. a task checkpointing its own container, or itself), and an error condition, in a manner analogous to a fork() call. We don't use copy_from_user()/copy_to_user() because it requires holding the entire image in user space, and does not make sense for restart. Also, we don't use a pipe, pseudo-fs file and the like, because they work by generating data on demand as the user pulls it (unless the entire image is buffered in the kernel) and would require more complex logic. They also would significantly complicate checkpoint that includes self. Changelog[v5]: - Config is 'def_bool n' by default Signed-off-by: Oren Laadan Acked-by: Serge Hallyn Signed-off-by: Dave Hansen --- arch/x86/include/asm/unistd_32.h | 2 + arch/x86/kernel/syscall_table_32.S | 2 + checkpoint/Kconfig | 11 +++++++++ checkpoint/Makefile | 5 ++++ checkpoint/sys.c | 41 ++++++++++++++++++++++++++++++++++++ include/linux/syscalls.h | 2 + init/Kconfig | 2 + kernel/sys_ni.c | 4 +++ 8 files changed, 69 insertions(+), 0 deletions(-) create mode 100644 checkpoint/Kconfig create mode 100644 checkpoint/Makefile create mode 100644 checkpoint/sys.c diff --git a/arch/x86/include/asm/unistd_32.h b/arch/x86/include/asm/unistd_32.h index f2bba78..a5f9e09 100644 --- a/arch/x86/include/asm/unistd_32.h +++ b/arch/x86/include/asm/unistd_32.h @@ -338,6 +338,8 @@ #define __NR_dup3 330 #define __NR_pipe2 331 #define __NR_inotify_init1 332 +#define __NR_checkpoint 333 +#define __NR_restart 334 #ifdef __KERNEL__ diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S index d44395f..5543136 100644 --- a/arch/x86/kernel/syscall_table_32.S +++ b/arch/x86/kernel/syscall_table_32.S @@ -332,3 +332,5 @@ ENTRY(sys_call_table) .long sys_dup3 /* 330 */ .long sys_pipe2 .long sys_inotify_init1 + .long sys_checkpoint + .long sys_restart diff --git a/checkpoint/Kconfig b/checkpoint/Kconfig new file mode 100644 index 0000000..ffaa635 --- /dev/null +++ b/checkpoint/Kconfig @@ -0,0 +1,11 @@ +config CHECKPOINT_RESTART + prompt "Enable checkpoint/restart (EXPERIMENTAL)" + def_bool n + depends on X86_32 && EXPERIMENTAL + help + Application checkpoint/restart is the ability to save the + state of a running application so that it can later resume + its execution from the time at which it was checkpointed. + + Turning this option on will enable checkpoint and restart + functionality in the kernel. diff --git a/checkpoint/Makefile b/checkpoint/Makefile new file mode 100644 index 0000000..07d018b --- /dev/null +++ b/checkpoint/Makefile @@ -0,0 +1,5 @@ +# +# Makefile for linux checkpoint/restart. +# + +obj-$(CONFIG_CHECKPOINT_RESTART) += sys.o diff --git a/checkpoint/sys.c b/checkpoint/sys.c new file mode 100644 index 0000000..375129c --- /dev/null +++ b/checkpoint/sys.c @@ -0,0 +1,41 @@ +/* + * Generic container checkpoint-restart + * + * Copyright (C) 2008 Oren Laadan + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of the Linux + * distribution for more details. + */ + +#include +#include + +/** + * sys_checkpoint - checkpoint a container + * @pid: pid of the container init(1) process + * @fd: file to which dump the checkpoint image + * @flags: checkpoint operation flags + * + * Returns positive identifier on success, 0 when returning from restart + * or negative value on error + */ +asmlinkage long sys_checkpoint(pid_t pid, int fd, unsigned long flags) +{ + pr_debug("sys_checkpoint not implemented yet\n"); + return -ENOSYS; +} +/** + * sys_restart - restart a container + * @crid: checkpoint image identifier + * @fd: file from which read the checkpoint image + * @flags: restart operation flags + * + * Returns negative value on error, or otherwise returns in the realm + * of the original checkpoint + */ +asmlinkage long sys_restart(int crid, int fd, unsigned long flags) +{ + pr_debug("sys_restart not implemented yet\n"); + return -ENOSYS; +} diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 04fb47b..9750393 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -621,6 +621,8 @@ asmlinkage long sys_timerfd_gettime(int ufd, struct itimerspec __user *otmr); asmlinkage long sys_eventfd(unsigned int count); asmlinkage long sys_eventfd2(unsigned int count, int flags); asmlinkage long sys_fallocate(int fd, int mode, loff_t offset, loff_t len); +asmlinkage long sys_checkpoint(pid_t pid, int fd, unsigned long flags); +asmlinkage long sys_restart(int crid, int fd, unsigned long flags); int kernel_execve(const char *filename, char *const argv[], char *const envp[]); diff --git a/init/Kconfig b/init/Kconfig index f763762..57364fe 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -814,6 +814,8 @@ config MARKERS source "arch/Kconfig" +source "checkpoint/Kconfig" + endmenu # General setup config HAVE_GENERIC_DMA_COHERENT diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index e14a232..fcd65cc 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -174,3 +174,7 @@ cond_syscall(compat_sys_timerfd_settime); cond_syscall(compat_sys_timerfd_gettime); cond_syscall(sys_eventfd); cond_syscall(sys_eventfd2); + +/* checkpoint/restart */ +cond_syscall(sys_checkpoint); +cond_syscall(sys_restart); -- 1.5.4.3