Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH v3 00/13] Virtually mapped stacks with guard pages (x86, core) | Date | Tue, 21 Jun 2016 11:24:18 +0200 |
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On Monday, June 20, 2016 4:43:30 PM CEST Andy Lutomirski wrote: > > On my laptop, this adds about 1.5µs of overhead to task creation, > which seems to be mainly caused by vmalloc inefficiently allocating > individual pages even when a higher-order page is available on the > freelist.
Would it help to have a fixed virtual address for the stack instead and map the current stack to that during a task switch, similar to how we handle fixmap pages?
That would of course trade the allocation overhead for a task switch overhead, which may be better or worse. It would also give "current" a constant address, which may give a small performance advantage but may also introduce a new attack vector unless we randomize it again.
Arnd
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