RE: [RFC PATCH v2 1/2] rseq: x86: implement abort-at-ip extension

[David Laight]

>  * [*] The openrisc, powerpc64 and x86-64 architectures define a "redzone" as a
>  *     stack area beyond the stack pointer which can be used by the compiler
>  *     to store local variables in leaf functions.

I wonder if that is really worth the trouble it causes!
By the time a function is spilling values to stack the cost
of a %sp update is almost certainly noise.

Someone clearly thought it was a 'good idea (tm)'.

	David

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