Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755388AbZGVKSa (ORCPT ); Wed, 22 Jul 2009 06:18:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754587AbZGVKS3 (ORCPT ); Wed, 22 Jul 2009 06:18:29 -0400 Received: from smtp161.dfw.emailsrvr.com ([67.192.241.161]:57001 "EHLO smtp161.dfw.emailsrvr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754195AbZGVKKk (ORCPT ); Wed, 22 Jul 2009 06:10:40 -0400 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, Serge Hallyn , Dave Hansen , Ingo Molnar , "H. Peter Anvin" , Alexander Viro , Pavel Emelyanov , Alexey Dobriyan , Oren Laadan , Oren Laadan Subject: [RFC v17][PATCH 18/60] c/r: create syscalls: sys_checkpoint, sys_restart Date: Wed, 22 Jul 2009 05:59:40 -0400 Message-Id: <1248256822-23416-19-git-send-email-orenl@librato.com> X-Mailer: git-send-email 1.6.0.4 In-Reply-To: <1248256822-23416-1-git-send-email-orenl@librato.com> References: <1248256822-23416-1-git-send-email-orenl@librato.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7778 Lines: 223 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 pid, a file descriptor (for the image file) and flags as arguments. The pid identifies the top-most (root) task in the process tree, e.g. the container init: for sys_checkpoint the first argument identifies the pid of the target container/subtree; for sys_restart it will identify the pid of restarting root task. 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[v17]: - Move checkpoint closer to namespaces (kconfig) - Kill "Enable" in c/r config option Changelog[v16]: - Change sys_restart() first argument to be 'pid_t pid' Changelog[v14]: - Change CONFIG_CHEKCPOINT_RESTART to CONFIG_CHECKPOINT (Ingo) - Remove line 'def_bool n' (default is already 'n') - Add CHECKPOINT_SUPPORT in Kconfig (Nathan Lynch) 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/Kconfig | 4 +++ arch/x86/include/asm/unistd_32.h | 2 + arch/x86/kernel/syscall_table_32.S | 2 + checkpoint/Kconfig | 14 ++++++++++++ checkpoint/Makefile | 5 ++++ checkpoint/sys.c | 41 ++++++++++++++++++++++++++++++++++++ include/linux/syscalls.h | 2 + init/Kconfig | 2 + kernel/sys_ni.c | 4 +++ 9 files changed, 76 insertions(+), 0 deletions(-) create mode 100644 checkpoint/Kconfig create mode 100644 checkpoint/Makefile create mode 100644 checkpoint/sys.c diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 738bdc6..97ec17c 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -85,6 +85,10 @@ config STACKTRACE_SUPPORT config HAVE_LATENCYTOP_SUPPORT def_bool y +config CHECKPOINT_SUPPORT + bool + default y if X86_32 + config FAST_CMPXCHG_LOCAL bool default y diff --git a/arch/x86/include/asm/unistd_32.h b/arch/x86/include/asm/unistd_32.h index f65b750..c25971b 100644 --- a/arch/x86/include/asm/unistd_32.h +++ b/arch/x86/include/asm/unistd_32.h @@ -343,6 +343,8 @@ #define __NR_rt_tgsigqueueinfo 335 #define __NR_perf_counter_open 336 #define __NR_clone_with_pids 337 +#define __NR_checkpoint 338 +#define __NR_restart 339 #ifdef __KERNEL__ diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S index 879e5ec..4741554 100644 --- a/arch/x86/kernel/syscall_table_32.S +++ b/arch/x86/kernel/syscall_table_32.S @@ -337,3 +337,5 @@ ENTRY(sys_call_table) .long sys_rt_tgsigqueueinfo /* 335 */ .long sys_perf_counter_open .long ptregs_clone_with_pids + .long sys_checkpoint + .long sys_restart diff --git a/checkpoint/Kconfig b/checkpoint/Kconfig new file mode 100644 index 0000000..ef7d406 --- /dev/null +++ b/checkpoint/Kconfig @@ -0,0 +1,14 @@ +# Architectures should define CHECKPOINT_SUPPORT when they have +# implemented the hooks for processor state etc. needed by the +# core checkpoint/restart code. + +config CHECKPOINT + bool "Checkpoint/restart (EXPERIMENTAL)" + depends on CHECKPOINT_SUPPORT && 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..8a32c6f --- /dev/null +++ b/checkpoint/Makefile @@ -0,0 +1,5 @@ +# +# Makefile for linux checkpoint/restart. +# + +obj-$(CONFIG_CHECKPOINT) += sys.o diff --git a/checkpoint/sys.c b/checkpoint/sys.c new file mode 100644 index 0000000..50c3cd8 --- /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 +#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 + */ +SYSCALL_DEFINE3(checkpoint, pid_t, pid, int, fd, unsigned long, flags) +{ + return -ENOSYS; +} + +/** + * sys_restart - restart a container + * @pid: pid of task root (in coordinator's namespace), or 0 + * @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 + */ +SYSCALL_DEFINE3(restart, pid_t, pid, int, fd, unsigned long, flags) +{ + return -ENOSYS; +} diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 80de700..33bce6e 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -754,6 +754,8 @@ asmlinkage long sys_pselect6(int, fd_set __user *, fd_set __user *, asmlinkage long sys_ppoll(struct pollfd __user *, unsigned int, struct timespec __user *, const sigset_t __user *, size_t); +asmlinkage long sys_checkpoint(pid_t pid, int fd, unsigned long flags); +asmlinkage long sys_restart(pid_t pid, 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 7503957..a083161 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -715,6 +715,8 @@ config NET_NS Allow user space to create what appear to be multiple instances of the network stack. +source "checkpoint/Kconfig" + config BLK_DEV_INITRD bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support" depends on BROKEN || !FRV diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index 68320f6..32f3f26 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -178,3 +178,7 @@ cond_syscall(sys_eventfd2); /* performance counters: */ cond_syscall(sys_perf_counter_open); + +/* checkpoint/restart */ +cond_syscall(sys_checkpoint); +cond_syscall(sys_restart); -- 1.6.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/