Oren, I see that patch 3/6 (deny external checkpoint unless frozen) in this set was merged in v14, but do you have any plans/objections to merging this optimization patch ? Serge had acked an earlier version of this patch.
Suka Sukadev Bhattiprolu [[email protected]] wrote: | | From: Sukadev Bhattiprolu <[email protected]> | Date: Thu, 12 Mar 2009 14:19:54 -0700 | Subject: [PATCH 3/6] 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]> | --- | checkpoint/checkpoint.c | 9 +++++++++ | 1 files changed, 9 insertions(+), 0 deletions(-) | | diff --git a/checkpoint/checkpoint.c b/checkpoint/checkpoint.c | index ed4fd3d..dae9b97 100644 | --- a/checkpoint/checkpoint.c | +++ b/checkpoint/checkpoint.c | @@ -341,11 +341,18 @@ 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) | @@ -401,6 +408,8 @@ 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
