Messages in this thread | | | Date | Thu, 24 Apr 2008 09:00:52 +0800 | From | Li Zefan <> | Subject | Re: [PATCH] cgroup: use read lock to guard find_existing_css_set() |
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Balbir Singh wrote: > Li Zefan wrote: >> The function does not modify anything (except the temporary >> css template), so it's sufficient to hold read lock. >> >> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> >> --- >> kernel/cgroup.c | 4 ++-- >> 1 files changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/kernel/cgroup.c b/kernel/cgroup.c >> index 2727f92..e9eb5da 100644 >> --- a/kernel/cgroup.c >> +++ b/kernel/cgroup.c >> @@ -406,11 +406,11 @@ static struct css_set *find_css_set( >> >> /* First see if we already have a cgroup group that matches >> * the desired set */ >> - write_lock(&css_set_lock); >> + read_lock(&css_set_lock); >> res = find_existing_css_set(oldcg, cgrp, template); >> if (res) >> get_css_set(res); >> - write_unlock(&css_set_lock); >> + read_unlock(&css_set_lock); >> >> if (res) >> return res; > > Looks good to me. Did you run lockdep? >
No, I found this when reading the code, but I do have done some test.
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