Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756935AbZCME3z (ORCPT ); Fri, 13 Mar 2009 00:29:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756796AbZCME3m (ORCPT ); Fri, 13 Mar 2009 00:29:42 -0400 Received: from smtp-out.google.com ([216.239.33.17]:43461 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750963AbZCME3k convert rfc822-to-8bit (ORCPT ); Fri, 13 Mar 2009 00:29:40 -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=Mr9vm3JWStXftnPp4eRL1lEF47mFPKPSjLuMeYU7Lr0be8fkqai3gou6ZltiNUdTs lyWy+BROyOLQtyTIddc+Q== MIME-Version: 1.0 In-Reply-To: <20090312212124.GA25019@us.ibm.com> References: <1234467035.3243.538.camel@calx> <1234475483.30155.194.camel@nimitz> <20090212141014.2cd3d54d.akpm@linux-foundation.org> <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> Date: Thu, 12 Mar 2009 21:29:32 -0700 Message-ID: <604427e00903122129y37ad791aq5fe7ef2552415da9@mail.gmail.com> Subject: Re: How much of a mess does OpenVZ make? ;) Was: What can OpenVZ do? From: Ying Han To: "Serge E. Hallyn" Cc: Greg Kurz , Cedric Le Goater , Andrew Morton , linux-api@vger.kernel.org, containers@lists.linux-foundation.org, mpm@selenic.com, linux-kernel@vger.kernel.org, Dave Hansen , linux-mm@kvack.org, tglx@linutronix.de, viro@zeniv.linux.org.uk, hpa@zytor.com, mingo@elte.hu, torvalds@linux-foundation.org, Alexey Dobriyan , xemul@openvz.org 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 Content-Length: 13488 Lines: 473 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. 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.. */ - #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; 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. + */ + if ((clone_flags & CLONE_NEWPID) && (clone_flags & CLONE_WITH_PID)) + return ERR_PTR(-EINVAL); + if ((clone_flags & CLONE_WITH_PID) && (clone_pid <= 1)) + return ERR_PTR(-EINVAL); + /* * Thread groups must share signals as well, and detached threads * can only be started up within the thread group. @@ -1135,7 +1144,10 @@ static struct task_struct *copy_process(unsigned long c if (pid != &init_struct_pid) { retval = -ENOMEM; - pid = alloc_pid(task_active_pid_ns(p)); + if (clone_flags & CLONE_WITH_PID) + pid = alloc_pid(task_active_pid_ns(p), clone_pid); + else + pid = alloc_pid(task_active_pid_ns(p), 0); if (!pid) goto bad_fork_cleanup_io; @@ -1162,6 +1174,8 @@ static struct task_struct *copy_process(unsigned long cl * Clear TID on mm_release()? */ p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NU + + #ifdef CONFIG_FUTEX p->robust_list = NULL; #ifdef CONFIG_COMPAT diff --git a/kernel/pid.c b/kernel/pid.c index 064e76a..0facf05 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -25,7 +25,7 @@ * Many thanks to Oleg Nesterov for comments and help * */ - +#define DEBUG #include #include #include @@ -122,12 +122,15 @@ static void free_pidmap(struct upid *upid) atomic_inc(&map->nr_free); } -static int alloc_pidmap(struct pid_namespace *pid_ns) +static int alloc_pidmap(struct pid_namespace *pid_ns, pid_t pid_nr) { int i, offset, max_scan, pid, last = pid_ns->last_pid; struct pidmap *map; - pid = last + 1; + if (pid_nr) + pid = pid_nr; + else + pid = last + 1; if (pid >= pid_max) pid = RESERVED_PIDS; offset = pid & BITS_PER_PAGE_MASK; @@ -153,9 +156,12 @@ static int alloc_pidmap(struct pid_namespace *pid_ns) do { if (!test_and_set_bit(offset, map->page)) { atomic_dec(&map->nr_free); - pid_ns->last_pid = pid; + if (!pid_nr) + pid_ns->last_pid = pid; return pid; } + if (pid_nr) + return -1; offset = find_next_offset(map, offset); pid = mk_pid(pid_ns, map, offset); /* @@ -239,21 +245,25 @@ void free_pid(struct pid *pid) call_rcu(&pid->rcu, delayed_put_pid); } -struct pid *alloc_pid(struct pid_namespace *ns) +struct pid *alloc_pid(struct pid_namespace *ns, pid_t pid_nr) { struct pid *pid; enum pid_type type; int i, nr; struct pid_namespace *tmp; struct upid *upid; + int level = ns->level; + + if (pid_nr >= pid_max) + return NULL; pid = kmem_cache_alloc(ns->pid_cachep, GFP_KERNEL); if (!pid) goto out; - tmp = ns; - for (i = ns->level; i >= 0; i--) { - nr = alloc_pidmap(tmp); + tmp = ns->parent; + for (i = level-1; i >= 0; i--) { + nr = alloc_pidmap(tmp, 0); if (nr < 0) goto out_free; @@ -262,6 +272,14 @@ struct pid *alloc_pid(struct pid_namespace *ns) tmp = tmp->parent; } + nr = alloc_pidmap(ns, pid_nr); + if (nr < 0) + goto out_free; + pid->numbers[level].nr = nr; + pid->numbers[level].ns = ns; + if (nr == pid_nr) + pr_debug("nr == pid_nr == %d\n", nr); + get_pid_ns(ns); pid->level = ns->level; atomic_set(&pid->count, 1); On Thu, Mar 12, 2009 at 2:21 PM, Serge E. Hallyn wrote: > > Quoting Greg Kurz (gkurz@fr.ibm.com): > > On Thu, 2009-03-12 at 09:53 -0500, Serge E. Hallyn wrote: > > > Or are you suggesting that you'll do a dummy clone of (5594,2) so that > > > the next clone(CLONE_NEWPID) will be expected to be (5594,3,1)? > > > > > > > Of course not > > Ok - someone *did* argue that at some point I think... > > > but one should be able to tell clone() to pick a specific > > pid. > > Can you explain exactly how? ?I must be missing something clever. > > -serge > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. ?For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org -- 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/