From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754436AbZCMGUI (ORCPT ); Fri, 13 Mar 2009 02:20:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751477AbZCMGTy (ORCPT ); Fri, 13 Mar 2009 02:19:54 -0400 Received: from smtp-out.google.com ([216.239.45.13]:42240 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751251AbZCMGTx convert rfc822-to-8bit (ORCPT ); Fri, 13 Mar 2009 02:19:53 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=mime-version:in-reply-to:references:date:message-id:subject:from:to: cc:content-type:content-transfer-encoding:x-system-of-record; b=K+vaNtQIPxF5BfL3pDeeYVF6vEVnYs9PgRKyQXo+uR7h5rkulTG8kw/ysvsl/cn9j 93rAPiCiMVUTLuOuTtKdA== MIME-Version: 1.0 In-Reply-To: <20090313053458.GA28833@us.ibm.com> References: <1234475483.30155.194.camel@nimitz> <1234479845.30155.220.camel@nimitz> <20090226155755.GA1456@x200.localdomain> <20090310215305.GA2078@x200.localdomain> <49B775B4.1040800@free.fr> <20090312145311.GC12390@us.ibm.com> <1236891719.32630.14.camel@bahia> <20090312212124.GA25019@us.ibm.com> <604427e00903122129y37ad791aq5fe7ef2552415da9@mail.gmail.com> <20090313053458.GA28833@us.ibm.com> Date: Thu, 12 Mar 2009 23:19:43 -0700 Message-ID: <604427e00903122319y4d98ffc3ub62547960181a2bf@mail.gmail.com> Subject: Re: How much of a mess does OpenVZ make? ;) Was: What can OpenVZ do? From: Ying Han To: Sukadev Bhattiprolu Cc: "Serge E. Hallyn" , linux-api@vger.kernel.org, containers@lists.linux-foundation.org, hpa@zytor.com, linux-kernel@vger.kernel.org, Dave Hansen , linux-mm@kvack.org, viro@zeniv.linux.org.uk, mingo@elte.hu, mpm@selenic.com, Andrew Morton , xemul@openvz.org, torvalds@linux-foundation.org, tglx@linutronix.de, Alexey Dobriyan Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thank you Sukadev for your comments. I will try to clean up my patch and repost it. --Ying On Thu, Mar 12, 2009 at 10:34 PM, Sukadev Bhattiprolu wrote: > Ying Han [yinghan@google.com] wrote: > | Hi Serge: > | I made a patch based on Oren's tree recently which implement a new > | syscall clone_with_pid. I tested with checkpoint/restart process tree > | and it works as expected. > > Yes, I think we had a version of clone() with pid a while ago. > > But it would be easier to review if you break it up into smaller > patches. and remove the unnecessary diffs in this patch like... > > > | This patch has some hack in it which i made a copy of libc's clone and > | made modifications of passing one more argument(pid number). I will > | try to clean up the code and do more testing. > | > | New syscall clone_with_pid > | Implement a new syscall which clone a thread with a preselected pid number. > | > | clone_with_pid(child_func, child_stack + CHILD_STACK - 16, > |                       CLONE_WITH_PID|SIGCHLD, pid, NULL); > | > | Signed-off-by: Ying Han > | > | diff --git a/arch/x86/include/asm/syscalls.h b/arch/x86/include/asm/syscalls.h > | index 87803da..b5a1b03 100644 > | --- a/arch/x86/include/asm/syscalls.h > | +++ b/arch/x86/include/asm/syscalls.h > | @@ -26,6 +26,7 @@ asmlinkage int sys_fork(struct pt_regs); > |  asmlinkage int sys_clone(struct pt_regs); > |  asmlinkage int sys_vfork(struct pt_regs); > |  asmlinkage int sys_execve(struct pt_regs); > | +asmlinkage int sys_clone_with_pid(struct pt_regs); > | > |  /* kernel/signal_32.c */ > |  asmlinkage int sys_sigsuspend(int, int, old_sigset_t); > | diff --git a/arch/x86/include/asm/unistd_32.h b/arch/x86/include/asm/unistd_32 > | index a5f9e09..f10ca0e 100644 > | --- a/arch/x86/include/asm/unistd_32.h > | +++ b/arch/x86/include/asm/unistd_32.h > | @@ -340,6 +340,7 @@ > |  #define __NR_inotify_init1   332 > |  #define __NR_checkpoint              333 > |  #define __NR_restart         334 > | +#define __NR_clone_with_pid  335 > | > |  #ifdef __KERNEL__ > | > | diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c > | index 0a1302f..88ae634 100644 > | --- a/arch/x86/kernel/process_32.c > | +++ b/arch/x86/kernel/process_32.c > | @@ -8,7 +8,6 @@ > |  /* > |   * This file handles the architecture-dependent parts of process handling.. > |   */ > | - > > these > > |  #include > | > |  #include > | @@ -652,6 +651,28 @@ asmlinkage int sys_clone(struct pt_regs regs) > |       return do_fork(clone_flags, newsp, ®s, 0, parent_tidptr, child_tidptr); > |  } > | > | +/** > | + * sys_clone_with_pid - clone a thread with pre-select pid number. > | + */ > | +asmlinkage int sys_clone_with_pid(struct pt_regs regs) > | +{ > | +     unsigned long clone_flags; > | +     unsigned long newsp; > | +     int __user *parent_tidptr, *child_tidptr; > | +     pid_t pid_nr; > | + > | +     clone_flags = regs.bx; > | +     newsp = regs.cx; > | +     parent_tidptr = (int __user *)regs.dx; > | +     child_tidptr = (int __user *)regs.di; > | +     pid_nr = regs.bp; > | + > | +     if (!newsp) > | +             newsp = regs.sp; > | +     return do_fork(clone_flags, newsp, ®s, pid_nr, parent_tidptr, > | +                     child_tidptr); > | +} > | + > |  /* > |   * This is trivial, and on the face of it looks like it > |   * could equally well be done in user mode. > | diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_tabl > | index 5543136..5191117 100644 > | --- a/arch/x86/kernel/syscall_table_32.S > | +++ b/arch/x86/kernel/syscall_table_32.S > | @@ -334,3 +334,4 @@ ENTRY(sys_call_table) > |       .long sys_inotify_init1 > |       .long sys_checkpoint > |       .long sys_restart > | +     .long sys_clone_with_pid > | diff --git a/arch/x86/mm/checkpoint.c b/arch/x86/mm/checkpoint.c > | index 50bde9a..a4aee65 100644 > | --- a/arch/x86/mm/checkpoint.c > | +++ b/arch/x86/mm/checkpoint.c > | @@ -7,7 +7,6 @@ > |   *  License.  See the file COPYING in the main directory of the Linux > |   *  distribution for more details. > |   */ > | - > |  #include > |  #include > | > | diff --git a/checkpoint/checkpoint.c b/checkpoint/checkpoint.c > | index 64155de..b7de611 100644 > | --- a/checkpoint/checkpoint.c > | +++ b/checkpoint/checkpoint.c > | @@ -8,6 +8,7 @@ > |   *  distribution for more details. > |   */ > | > | +#define DEBUG > |  #include > |  #include > |  #include > | @@ -564,3 +565,4 @@ int do_checkpoint(struct cr_ctx *ctx, pid_t pid) > |   out: > |       return ret; > |  } > | + > | diff --git a/checkpoint/ckpt_file.c b/checkpoint/ckpt_file.c > | index e3097ac..a8c5ad5 100644 > | --- a/checkpoint/ckpt_file.c > | +++ b/checkpoint/ckpt_file.c > | @@ -7,7 +7,7 @@ > |   *  License.  See the file COPYING in the main directory of the Linux > |   *  distribution for more details. > |   */ > | - > | +#define DEBUG > |  #include > |  #include > |  #include > | diff --git a/checkpoint/ckpt_mem.c b/checkpoint/ckpt_mem.c > | index 4925ff2..ca5840b 100644 > | --- a/checkpoint/ckpt_mem.c > | +++ b/checkpoint/ckpt_mem.c > | @@ -7,7 +7,7 @@ > |   *  License.  See the file COPYING in the main directory of the Linux > |   *  distribution for more details. > |   */ > | - > | +#define DEBUG > |  #include > |  #include > |  #include > | diff --git a/checkpoint/restart.c b/checkpoint/restart.c > | index 7ec4de4..30e43c2 100644 > | --- a/checkpoint/restart.c > | +++ b/checkpoint/restart.c > | @@ -8,6 +8,7 @@ > |   *  distribution for more details. > |   */ > | > | +#define DEBUG > |  #include > |  #include > |  #include > | @@ -242,7 +243,7 @@ static int cr_read_task_struct(struct cr_ctx *ctx) > |               memcpy(t->comm, buf, min(hh->task_comm_len, TASK_COMM_LEN)); > |       } > |       kfree(buf); > | - > | +     pr_debug("read task %s\n", t->comm); > |       /* FIXME: restore remaining relevant task_struct fields */ > |   out: > |       cr_hbuf_put(ctx, sizeof(*hh)); > | diff --git a/checkpoint/rstr_file.c b/checkpoint/rstr_file.c > | index f44b081..755e40e 100644 > | --- a/checkpoint/rstr_file.c > | +++ b/checkpoint/rstr_file.c > | @@ -7,7 +7,7 @@ > |   *  License.  See the file COPYING in the main directory of the Linux > |   *  distribution for more details. > |   */ > | - > | +#define DEBUG > |  #include > |  #include > |  #include > | diff --git a/checkpoint/rstr_mem.c b/checkpoint/rstr_mem.c > | index 4d5ce1a..8330468 100644 > | --- a/checkpoint/rstr_mem.c > | +++ b/checkpoint/rstr_mem.c > | @@ -7,7 +7,7 @@ > |   *  License.  See the file COPYING in the main directory of the Linux > |   *  distribution for more details. > |   */ > | - > | +#define DEBUG > |  #include > |  #include > |  #include > | diff --git a/checkpoint/sys.c b/checkpoint/sys.c > | index f26b0c6..d1a5394 100644 > | --- a/checkpoint/sys.c > | +++ b/checkpoint/sys.c > | @@ -7,7 +7,7 @@ > |   *  License.  See the file COPYING in the main directory of the Linux > |   *  distribution for more details. > |   */ > | - > | +#define DEBUG > |  #include > |  #include > |  #include > | @@ -263,7 +263,6 @@ asmlinkage long sys_checkpoint(pid_t pid, int fd, unsigned > |               return PTR_ERR(ctx); > | > |       ret = do_checkpoint(ctx, pid); > | - > |       if (!ret) > |               ret = ctx->crid; > | > | @@ -304,3 +303,4 @@ asmlinkage long sys_restart(int crid, int fd, unsigned lon > |       cr_ctx_put(ctx); > |       return ret; > |  } > | + > | diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h > | index 217cf6e..bc2c202 100644 > | --- a/include/linux/checkpoint.h > | +++ b/include/linux/checkpoint.h > | @@ -114,7 +114,6 @@ extern int cr_write_files(struct cr_ctx *ctx, struct task_ > |  extern int do_restart(struct cr_ctx *ctx, pid_t pid); > |  extern int cr_read_mm(struct cr_ctx *ctx); > |  extern int cr_read_files(struct cr_ctx *ctx); > | - > |  #ifdef pr_fmt > |  #undef pr_fmt > |  #endif > | diff --git a/include/linux/pid.h b/include/linux/pid.h > | index d7e98ff..86e2f61 100644 > | --- a/include/linux/pid.h > | +++ b/include/linux/pid.h > | @@ -119,7 +119,7 @@ extern struct pid *find_get_pid(int nr); > |  extern struct pid *find_ge_pid(int nr, struct pid_namespace *); > |  int next_pidmap(struct pid_namespace *pid_ns, int last); > | > | -extern struct pid *alloc_pid(struct pid_namespace *ns); > | +extern struct pid *alloc_pid(struct pid_namespace *ns, pid_t pid_nr); > |  extern void free_pid(struct pid *pid); > | > |  /* > | diff --git a/include/linux/sched.h b/include/linux/sched.h > | index 0150e90..7fb4e28 100644 > | --- a/include/linux/sched.h > | +++ b/include/linux/sched.h > | @@ -28,6 +28,7 @@ > |  #define CLONE_NEWPID         0x20000000      /* New pid namespace */ > |  #define CLONE_NEWNET         0x40000000      /* New network namespace */ > |  #define CLONE_IO             0x80000000      /* Clone io context */ > | +#define CLONE_WITH_PID               0x00001000      /* Clone with pre-select PID */ > | > |  /* > |   * Scheduling policies > | diff --git a/kernel/exit.c b/kernel/exit.c > | index 2d8be7e..4baf651 100644 > | --- a/kernel/exit.c > | +++ b/kernel/exit.c > | @@ -3,7 +3,7 @@ > |   * > |   *  Copyright (C) 1991, 1992  Linus Torvalds > |   */ > | - > | +#define DEBUG > |  #include > |  #include > |  #include > | @@ -1676,6 +1676,7 @@ static long do_wait(enum pid_type type, struct pid *pid, > |       DECLARE_WAITQUEUE(wait, current); > |       struct task_struct *tsk; > |       int retval; > | +     int level; > > and this (level is not used). > | > |       trace_sched_process_wait(pid); > | > | @@ -1708,7 +1709,6 @@ repeat: > |                       retval = tsk_result; > |                       goto end; > |               } > | - > |               if (options & __WNOTHREAD) > |                       break; > |               tsk = next_thread(tsk); > | @@ -1817,7 +1817,6 @@ asmlinkage long sys_wait4(pid_t upid, int __user *stat_a > |               type = PIDTYPE_PID; > |               pid = find_get_pid(upid); > |       } > | - > |       ret = do_wait(type, pid, options | WEXITED, NULL, stat_addr, ru); > |       put_pid(pid); > | > | diff --git a/kernel/fork.c b/kernel/fork.c > | index 085ce56..262ae1e 100644 > | --- a/kernel/fork.c > | +++ b/kernel/fork.c > | @@ -10,7 +10,7 @@ > |   * Fork is rather simple, once you get the hang of it, but the memory > |   * management can be a bitch. See 'mm/memory.c': 'copy_page_range()' > |   */ > | - > | +#define DEBUG > |  #include > |  #include > |  #include > | @@ -959,10 +959,19 @@ static struct task_struct *copy_process(unsigned long cl > |       int retval; > |       struct task_struct *p; > |       int cgroup_callbacks_done = 0; > | +     pid_t clone_pid = stack_size; > | > |       if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) > |               return ERR_PTR(-EINVAL); > | > | +     /* We only allow the clone_with_pid when a new pid namespace is > | +      * created. FIXME: how to restrict it. > > Not sure why CLONE_NEWPID is required to set pid_nr. In fact with CLONE_NEWPID, > by definition, pid_nr should be 1. Also, what happens if a container has > more than one process - where the second process has a pid_nr > 2 ? >