Quoting Sukadev Bhattiprolu ([email protected]): > > From: Sukadev Bhattiprolu <[email protected]> > Subject: [PATCH 4/5] Check 'may_checkpoint()' early > > We currently check if a task is checkpointable when writing the task > information to checkpoint file. The small downside of doing this check > late is that we may have processed several processes in the tree before > hitting one that cannot be checkpointed. > > We anyway walk the process tree we are checkpointing earlier, while > counting the tasks. We could check if all processes in the tree are > checkpointable at that time and fail early if any of them are not. > Since the process tree should be frozen, checking earlier should not > matter ? > > For now, the patch leaves the existing check in cr_write_pids(). We > can remove that later. > > Signed-off-by: Sukadev Bhattiprolu <[email protected]>
Yes this seems like a good idea to me. Acked-by: Serge Hallyn <[email protected]> > --- > checkpoint/checkpoint.c | 9 +++++++++ > 1 files changed, 9 insertions(+), 0 deletions(-) > > diff --git a/checkpoint/checkpoint.c b/checkpoint/checkpoint.c > index fbcd9eb..9189abb 100644 > --- a/checkpoint/checkpoint.c > +++ b/checkpoint/checkpoint.c > @@ -346,11 +346,18 @@ static int cr_tree_count_tasks(struct cr_ctx *ctx) > struct task_struct **tasks_arr = ctx->tasks_arr; > int tasks_nr = ctx->tasks_nr; > int nr = 0; > + int ret; > > read_lock(&tasklist_lock); > > /* count tasks via DFS scan of the tree */ > while (1) { > + ret = cr_may_checkpoint_task(task, ctx); > + if (ret < 0) { > + nr = ret; > + break; > + } > + > if (tasks_arr) { > /* unlikely, but ... */ > if (nr == tasks_nr) > @@ -406,6 +413,8 @@ static int cr_build_tree(struct cr_ctx *ctx) > > /* count tasks (no side effects) */ > n = cr_tree_count_tasks(ctx); > + if (n < 0) > + return n; > > ctx->tasks_nr = n; > ctx->tasks_arr = kzalloc(n * sizeof(*ctx->tasks_arr), GFP_KERNEL); > -- > 1.5.2.5 > > _______________________________________________ > Containers mailing list > [email protected] > https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
