If a file mmaped or pointed by exe link is unlinked, we will
generate a ghost file for it. On restore the ghost file will
be created with the users counter 1 and the very first open
(e.g. for mmap) will unlink the file.
Handle this by bumping up user counter for every mapping
pointing on the file.
This appeared after previous patches that packed the reg-files
image. Before it each vma and exe link created separate entry
in the reg-files image.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
When writing VMAs we perform too many small writes into vma-.img files.
This can be easily fixed by moving the vma-s into mm-s, all the more
so they cannot be splitted from each other.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
On restore we will read all VmaEntries in one big MmEntry object,
so to avoif copying them all into vma_areas, make them be pointable.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Right now we do it two times -- on shmem prepare and
on the restore itself. Make collection only once as
we do for fdinfo-s -- root task reads all stuff in and
populates tasks' rst_info with it.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
When reading pagemaps, we read it from specific position. To
do it, we called lseek, then read. Fortunetely, there's a
syscall that does both things in one call -- pread. Since
we don't need to keep pagemap's position for further reads,
it perfectly suits our needs.
This removes 75% of lseek calls when dumping basic container.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
If someone reads untouched page, the kernel maps the zero page
to this address. This page will not have the SOFT_DIRTY bit and it must
not be dumped.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
When writing pagemaps to page-server we want both page-*.img and pagemap-*.img
to be on remote host. But the subsequent pre-dump/dump with parent images will
try to access pagemap-*img-s to check for hole dumped being present in it.
To handle this, move checks for hole being backed by something in parent into
page-local-xfer. In case of page-server dump it will be page-server who will
check the holes when writing them.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
We have a big mistake in how we track for ptes to be SOFT_DIRTY -- no
need in these checks if the --track-mem is not given.
While fixing this, remember proper checks for the kernel memory tracker.
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Reported-by: Tim Schürmann <info@tim-schuermann.de>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Remove whitespace at EOL (found by git grep ' $')
To people using vim, I'd suggest adding the following code to ~/.vimrc:
let c_space_errors = 1
highlight FormatError ctermbg=darkred guibg=darkred
match FormatError /\s\+$\|\ \+\t\|\%80v.\|\ \{8\}/
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
fcntl data is arch independent, so move it out of include/asm/type.h
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
The version, that might not wait for ack is always called with
"async" flag set. Cleanup things according to this.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This file was created for backward compatibility with
not-yet-patched kernel. Now we can remove it.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
These processes don't have image files in a parent snapshot and crtools
should not fail in this case.
https://bugzilla.openvz.org/show_bug.cgi?id=2636
v2: return NULL from mem_snap_init, if a parent image is absent.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This patch prevents page dump failure screening
by the PARASITE_CMD_MPROTECT_VMAS command success.
Signed-off-by: Alexander Kartashov <alekskartashov@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Parasite daemon mode it quite tricky. One may consider
it as consisting of two parts
- daemon mode for thread leader
- daemon mode for regular threads
Thread leader daemon
--------------------
Once thread leader parasite code switched initialized,
it starts spinning on socket listening for commands
to handle.
If the command destination is the thread leader itself it
handles it and replies back the ack to the caller (iow
the main crtools code).
If the recepient is not thread leader but one of threads,
then thread leader wakes up the thread by futex and makes
it to handle the command waiting on futex for result. Once
result obtained, the ack is being sending back to caller.
Thread daemon
-------------
On initialization thread daemon starts waiting a command on futex.
The futex is triggered by thread leader daemon when command received.
Once command is received and handled, the result is reported back to
the thread leader daemon, which in turn send ack message.
Both thread-leader and regular threads require own stack to operate
on since they all are present in memory simultaneously. Thus we use
call_daemon_thread() helper which takes care of providing stack
to the callee.
TODO:
- ARM requires own wrappers on damonize/trap low-level code,
at moment x86-64 is only covered
v2: remove PARASITE_CMD_DAEMONIZED and s->ack
parasite: use a propper command for getting ack
Fixed-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
They are relying on trap being issued at the end of execution
so to distinguish it with future daemon mode add "trap" postfix
to them.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This constants are system wide, so move them to mem.h
header for reuse sake.
[ xemul: It was kerndat.h in the patch ]
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
The soft-dirty API has changed slightly -- now the bit in
question _is_ in pagemap file (not pagemap2) but to see it
we have to reset soft-dirty for anyone first.
Teach the kerndat soft-dirty checker this fact. The actual
pagemap reading code already knows select pagemap/pagemap2
file itself.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
pages_scanned -- the amount of pages criu looked at for decision
pages_skipped_parent -- the amount of pages that were skipped, due to
they are present in parent image
pages_writted -- the amount of pages criu transfered into image
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
With this action criu will seize tasks, grab all its memory into
page-pipes, rest dirty tracker and will then release them. Writing
the memory from page-pipes would occur after tasks are unfreezed
and thus the frozen time should become reasonably small.
When pre-dump is in action, the dirty tracking is forcedly turned
off as well as tasks are resumed afterwards, not killed, by default.
This is a prerequisite for iterative migration.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Dumping memory is draining it from parasite, for pre-dump
this time would be reasonably small. _Writing_ the memory
would occur _after_ tasks unseize and resume.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
They are not documented, thus OK for now. Two options --
* one to specify where the parent images are
* one to reset dirty memory tracking
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
This is required for (soon to be) pre-dump command -- this command
will have to keep parasite args with pagemap (iovecs) some time after
parasite is executed. Since we call mprotect cmd _after_ pages dump
we can thus spoil these iovecs. To address this vmas to mprotect and
iovecs to dump are located in one parasite args area one after another
without intersections.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
It's quite simple -- get parent's pagemap before dumping memory,
then collect _full_ pagemap of task putting holes into page-pipe
when the page is (soft-dirty-clear && in-parent-map). At the end
reset task's soft-dirty bits.
This requires kernel support from
http://comments.gmane.org/gmane.linux.kernel.mm/98283
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
