Messages in this thread | | | From | Boqun Feng <> | Subject | [PATCH 0/2] completion: Reduce stack usage caused by COMPLETION_INITIALIZER_ONSTACK() | Date | Wed, 23 Aug 2017 23:25:36 +0800 |
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With LOCKDEP_CROSSRELEASE and LOCKDEP_COMPLETIONS introduced, the growth in kernel stack usage of several functions were reported:
https://marc.info/?l=linux-kernel&m=150270063231284&w=2
The root cause of this is in COMPLETION_INITIALIZER_ONSTACK(), we use
({init_completion(&work); work})
, which will create a temporary object when returned. However this temporary object is unnecessary. And this patch fixes it by making the statement expression in COMPLETION_INITIALIZER_ONSTACK() return a pointer rather than a whole structure. This will reduce the stack usage even if !LOCKDEP.
However, such a change does make one COMPLETION_INITIALIZER_ONSTACK() callsite invalid, so we fix this first via converting to init_completion().
Regards, Boqun
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