[Devel] Re: [PATCH 1/5] c/r: introduce ckpt_task_vnr(), ckpt_pid_vnr()

[Oren Laadan]

Note that you also need to apply the corresponding user-cr patchset
to sync the userspace tools with this new logic.

Oren.

On 01/26/2011 11:20 AM, Oren Laadan wrote:
> 
> Hmmm.. the cover post did not make it :(
> 
> This patch-set changes the way pids are handled in c/r - instead
> of simple pid numbers, we now treat them as proper shared objects.
> 
> The patch applies on top of the most recent branch 'ckpt-v23-rc1' 
> of c/r (for 2.6.37 kernel).
> 
> Thanks,
> 
> Oren.
> 
> On 01/26/2011 11:10 AM, Oren Laadan wrote:
>> This helpoer is Useful to get the pid from the root task's (checkpoint
>> or restart) point of view.
>>
>> Signed-off-by: Oren Laadan <orenl at cs.columbia.edu>
>> ---
>>  include/linux/checkpoint.h     |   10 +++++++++-
>>  kernel/checkpoint/checkpoint.c |    5 +++--
>>  kernel/checkpoint/restart.c    |    6 ++----
>>  kernel/signal.c                |    2 +-
>>  4 files changed, 15 insertions(+), 8 deletions(-)
>>
>> diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
>> index c015106..fe61edb 100644
>> --- a/include/linux/checkpoint.h
>> +++ b/include/linux/checkpoint.h
>> @@ -110,8 +110,16 @@ extern int checkpoint_dump_page(struct ckpt_ctx *ctx, struct page *page);
>>  extern int restore_read_page(struct ckpt_ctx *ctx, struct page *page);
>>  
>>  /* pids */
>> -extern pid_t ckpt_pid_nr(struct ckpt_ctx *ctx, struct pid *pid);
>>  extern struct pid *_ckpt_find_pgrp(struct ckpt_ctx *ctx, pid_t pgid);
>> +static inline pid_t ckpt_task_vnr(struct ckpt_ctx *ctx, struct task_struct *task)
>> +{
>> +	return task_pid_nr_ns(task, ctx->root_nsproxy->pid_ns);
>> +}
>> +static inline pid_t ckpt_pid_vnr(struct ckpt_ctx *ctx, struct pid *pid)
>> +{
>> +	return pid_nr_ns(pid, ctx->root_nsproxy->pid_ns);
>> +}
>> +extern int ckpt_lookup_pid(struct ckpt_ctx *ctx, struct pid *pid);
>>  
>>  /* defined in objhash.c and also used in security/security.c */
>>  extern void lsm_string_free(struct kref *kref);
>> diff --git a/kernel/checkpoint/checkpoint.c b/kernel/checkpoint/checkpoint.c
>> index 0f46acf..7cd491b 100644
>> --- a/kernel/checkpoint/checkpoint.c
>> +++ b/kernel/checkpoint/checkpoint.c
>> @@ -28,6 +28,7 @@
>>  #include <linux/hrtimer.h>
>>  #include <linux/deferqueue.h>
>>  #include <linux/checkpoint.h>
>> +#include <linux/flex_array.h>
>>  #include <linux/pid_namespace.h>
>>  
>>  /* unique checkpoint identifier (FIXME: should be per-container ?) */
>> @@ -243,10 +244,10 @@ static int may_checkpoint_task(struct ckpt_ctx *ctx, struct task_struct *t)
>>  {
>>  	struct task_struct *root = ctx->root_task;
>>  	struct nsproxy *nsproxy;
>> -	int ret = 0;
>>  	struct pid_namespace *pidns;
>> +	int ret = 0;
>>  
>> -	ckpt_debug("check %d\n", task_pid_nr_ns(t, ctx->root_nsproxy->pid_ns));
>> +	ckpt_debug("check %d\n", ckpt_task_vnr(ctx, t));
>>  
>>  	if (t->exit_state == EXIT_DEAD) {
>>  		_ckpt_err(ctx, -EBUSY, "%(T)Task state EXIT_DEAD\n");
>> diff --git a/kernel/checkpoint/restart.c b/kernel/checkpoint/restart.c
>> index 2eae499..e844568 100644
>> --- a/kernel/checkpoint/restart.c
>> +++ b/kernel/checkpoint/restart.c
>> @@ -913,8 +913,7 @@ static int wait_task_active(struct ckpt_ctx *ctx)
>>  
>>  static int wait_task_sync(struct ckpt_ctx *ctx)
>>  {
>> -	ckpt_debug("pid %d syncing\n",
>> -		task_pid_nr_ns(current, task_active_pid_ns(ctx->root_task)));
>> +	ckpt_debug("pid %d syncing\n", ckpt_task_vnr(ctx, current));
>>  	wait_event_interruptible(ctx->waitq, ckpt_test_complete(ctx));
>>  	ckpt_debug("task sync done (errno %d)\n", ctx->errno);
>>  	if (ckpt_test_error(ctx))
>> @@ -1187,10 +1186,9 @@ static struct task_struct *choose_root_task(struct ckpt_ctx *ctx, pid_t pid)
>>  
>>  	read_lock(&tasklist_lock);
>>  	list_for_each_entry(task, &current->children, sibling) {
>> -		if (task_pid_nr_ns(task, ctx->coord_pidns) == pid) {
>> +		if (task_pid_vnr(task) == pid) {
>>  			get_task_struct(task);
>>  			ctx->root_task = task;
>> -			ctx->root_pid = pid;
>>  			break;
>>  		}
>>  	}
>> diff --git a/kernel/signal.c b/kernel/signal.c
>> index b1e6a31..dca40be 100644
>> --- a/kernel/signal.c
>> +++ b/kernel/signal.c
>> @@ -3352,7 +3352,7 @@ static int restore_signal(struct ckpt_ctx *ctx)
>>  			 * fail, so no need for explicit test
>>  			 */
>>  			ret = do_tiocspgrp(tty, tty_pair_get_tty(tty),
>> -					   h->tty_pgrp);
>> +					   pid_vnr(pgrp));
>>  			if (ret < 0)
>>  				goto out;
>>  		}
> 
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