On Tue, Jan 29, 2013 at 08:52:45AM +0900, Kamezawa Hiroyuki wrote:
(2013/01/28 19:36), Daniel P. Berrange wrote:
On Mon, Jan 28, 2013 at 02:37:11PM +0800, Gao feng wrote:
Now we mount /dev as tmpfs and haven't created directory /dev/shm,so the glibc api such as shm_open/sem_open will create files under dir /dev.(since /dev is mounted as tmpfs)
Through these api still useable in container,but this cause directory /dev looks a little chaos.
This patch create directory /dev/shm automatically,the files created by shm_open/sem_open will stay in this directroy.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> --- src/lxc/lxc_container.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c index 497539c..5150564 100644 --- a/src/lxc/lxc_container.c +++ b/src/lxc/lxc_container.c @@ -586,6 +586,13 @@ static int lxcContainerMountBasicFS(bool pivotRoot, "devfs", "/dev", "tmpfs", opts); goto cleanup; } + + VIR_DEBUG("create directory /dev/shm for POSIX shared memory and named semphore"); + if (virFileMakePath("/dev/shm") < 0) { + virReportSystemError(errno, "%s", + _("Failed to mkdir /dev/shm")); + goto cleanup; + } }
rc = 0;
I we probably want to mount a separate tmpfs on /dev/shm really, so we can do resource limits on /dev and /dev/shm separately.
I agree. BTW, if the user wants to tune limit of /dev/shm size, he need to add
<filesystem type='ram'> <source usage='XXXXX'/> <target dir='/dev/shm'/> </filesystem>
Oh true, I forgot we added that. That is fine.
How do you think suitable limit for default should be ? half of memory limit of a container ?
I think /dev can just be limited to say 1 MB - it should only ever contain device nodes which have little space requirement. If someone actually wants to be using SHM, then they shuld explicitly configure /dev/shm in the XML with a suitable limit. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|