Messages in this thread | | | Subject | Re: [V2][PATCH] cgroup: fix memory leak caused by missing cgroup_bpf_offline | From | Quanyang Wang <> | Date | Wed, 20 Oct 2021 13:16:01 +0800 |
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Hi Michal,
On 10/20/21 1:10 AM, Michal Koutný wrote: > Hi. > > On Tue, Oct 19, 2021 at 06:41:14PM +0800, Quanyang Wang <quanyang.wang@windriver.com> wrote: >> So I add 2 "Fixes tags" here to indicate that 2 commits introduce two >> different issues. > > AFAIU, both the changes are needed to cause the leak, a single patch > alone won't cause the issue. Is that correct? (Perhaps not as I realize, > see below.) Yes, I back to the earlier commit 4bfc0bb2c60e and no memory leak is observed. > > But on second thought, the problem is the missing percpu_ref_exit() in > the (root) cgroup release path and percpu counter would allocate the > percpu_count_ptr anyway, so 4bfc0bb2c60e is only making the leak more > visible. Is this correct? No, the earlier commit 4bfc0bb2c60e introduces a imbalance and the later commit 2b0d3d3e4fcf introduces a visible leak.
Thanks, Quanyang > > I agree the commit 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of > percpu_ref in fast path") alone did nothing wrong. > > [On a related (but independent) note, there seems to be an optimization > opportunity in not dealing with cgroup_bpf at all on the non-default > hierarchies.] > > Regards, > Michal >
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