Messages in this thread | | | Date | Wed, 22 Feb 2023 12:06:20 -0500 | From | Johannes Weiner <> | Subject | Re: [PATCH] mm/khugepaged: alloc_charge_hpage() take care of mem charge errors |
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Hello,
On Tue, Feb 21, 2023 at 04:43:44PM -0500, Peter Xu wrote: > If memory charge failed, the caller shouldn't call mem_cgroup_uncharge(). > Let alloc_charge_hpage() handle the error itself and clear hpage properly > if mem charge fails.
I'm a bit confused by this patch.
There isn't anything wrong with calling mem_cgroup_uncharge() on an uncharged page, functionally. It checks and bails out.
It's an unnecessary call of course, but since it's an error path it's also not a cost issue, either.
I could see an argument for improving the code, but this is actually more code, and the caller still has the uncharge-and-put branch anyway for when the collapse fails later on.
So I'm not sure I understand the benefit of this change.
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