Re: serious performance regression due to NX patch

Ingo Molnar
2004-07-11T08:38:03Z

On Fri, 9 Jul 2004, David Mosberger wrote:

> The "No eXecute patch for x86" causes a serious exec() performance
> degradation on ia64 since it ends up incorrectly turning on the execute
> protection on all segments (since most ia64 binaries don't have a
> gnu_stack program-header).
>
> The patch below fixes the problem by turning on VM_EXEC and VM_MAYEXEC
> only if VM_DATA_DEFAULT_FLAGS mentions them. Note that on ia64, the
> value of VM_DATA_DEFAULT_FLAGS depends on the personality (to support
> x86 binaries) and hence I had to move the setting of "def_flags" down a
> bit to a point after SET_PERSONALITY() has been done.
>
> Please apply.

ok, agreed. I'll check that it still does the right thing on x86.

Ingo