On Thu, 11 Mar 2021 13:56:15 +0800 Yejune Deng <yejune.deng@xxxxxxxxx> wrote: > refcount_t type should be used instead of atomic_t when the variable > is used as a reference counter. This is because the implementation of > refcount_t can prevent overflows and detect possible use-after-free. The use of refcount_t comes at a cost: q:/usr/src/25> size mm/rmap.o text data bss dec hex filename 31114 2147 32 33293 820d mm/rmap.o 31558 2147 32 33737 83c9 mm/rmap.o That's a bunch more instructions to execute on some fairly hot code paths. I guess the debugging/checking features are nice, but this is pretty mature code. I'm quite unsure that this tradeoff is a favorable one.
