This commit brings the former "Rewrite task/threads stopping engine"
commit back. Handling it separately is too complex so better try
to handle it in-place.
Note some tests might fault, it's expected.
---
Stopping tasks with STOP and proceeding with SEIZE is actually excessive --
the SEIZE if enough. Moreover, just killing a task with STOP is also racy,
since task should be given some time to come to sleep before its proc
can be parsed.
Rewrite all this code to SEIZE task and all its threads from the very beginning.
With this we can distinguish stopped task state and migrate it properly (not
supported now, need to implement).
This thing however has one BIG problem -- after we SEIZE-d a task we should
seize
it's threads, but we should do it in a loop -- reading /proc/pid/task and
seizing
them again and again, until the contents of this dir stops changing (not done
now).
Besides, after we seized a task and all its threads we cannot scan it's children
list once -- task can get reparented to init and any task's child can call clone
with CLONE_PARENT flag thus repopulating the children list of the already seized
task (not done also)
This patch is ugly, yes, but splitting it doesn't help to review it much, sorry
:(
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Stopping tasks with STOP and proceeding with SEIZE is actually excessive --
the SEIZE if enough. Moreover, just killing a task with STOP is also racy,
since task should be given some time to come to sleep before its proc
can be parsed.
Rewrite all this code to SEIZE task and all its threads from the very beginning.
With this we can distinguish stopped task state and migrate it properly (not
supported now, need to implement).
This thing however has one BIG problem -- after we SEIZE-d a task we should seize
it's threads, but we should do it in a loop -- reading /proc/pid/task and seizing
them again and again, until the contents of this dir stops changing (not done now).
Besides, after we seized a task and all its threads we cannot scan it's children
list once -- task can get reparented to init and any task's child can call clone
with CLONE_PARENT flag thus repopulating the children list of the already seized
task (not done also)
This patch is ugly, yes, but splitting it doesn't help to review it much, sorry :(
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
We do not want to use pr_perror() here, because
1. fscanf only sets errno in case it returns EOF
2. we are not really interested in errno value
So use pr_err() instead.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
* kid -> child
* First letter should be uppercase
* Misc typos in messages and comments
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
proc_parse.c: In function ‘parse_maps’:
proc_parse.c:75:6: error: format ‘%Lu’ expects type ‘long long unsigned int’, but argument 5 has type ‘u64’
proc_parse.c:118:5: error: format ‘%Lu’ expects type ‘long long unsigned int’, but argument 5 has type ‘u64’
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
This is a standard convention to print error message (i.e. strerror(errno))
at the end of line, like this:
Cannot remove file: Permission denied
So pr_perror is fixed to follow this convention (using GNU extension
%m helps a lot here). Unfortunately, due to this we have to make
pr_perror() print a new line character, too, so we had to strip it
from the all pr_perror() invocations.
That (appending a newline) also makes pr_perror() a black sheep
in the herd of pr_* helpers, but what can we do? Worst case scenario
is an extra newline after an error message, not too harmful.
An alternative approach (stripping the newline from the passed format
string and re-adding it) was discussed thoroughly, and it was decided
that such a hack looks a bit too dirty.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
All the IDs and caps are in there. Just read them for future use.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Requires patch #14 (for kernel). Also check for number of entries read be
at least required, not exactly equal for forward compatibility.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
And do not use strcpy, better to stick with strncpy.
Moreover, to be on a safe side make proc internal
buffer big enough even for "(%16s)" format, it's
hardly possible that the kernel ever change stat
format but just to be on a safe side.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
We will later need other fields of this file, so let's parse it right
now in a way, that allows to easily get new fields.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
