Re: [libvirt] [PATCH] LXC: create directory /dev/shm automatically

(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(a)cn.fujitsu.com&gt; >>--- >> 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>

How do you think suitable limit for default should be ? half of memory limit of a container ?