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 ?