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| author | Ingo Molnar <[email protected]> | 2008-08-13 16:02:18 +0000 |
|---|---|---|
| committer | Ingo Molnar <[email protected]> | 2008-08-15 17:17:33 +0000 |
| commit | 2fdc86901d2ab30a12402b46238951d2a7891590 (patch) | |
| tree | 8f514c642a9b541ba474c68272c8a38104d8a1cd /lib/debugobjects.c | |
| parent | x86: fix section mismatch warning - spp_getpage() (diff) | |
| download | kernel-2fdc86901d2ab30a12402b46238951d2a7891590.tar.gz kernel-2fdc86901d2ab30a12402b46238951d2a7891590.zip | |
x86: add MAP_STACK mmap flag
as per this discussion:
http://lkml.org/lkml/2008/8/12/423
Pardo reported that 64-bit threaded apps, if their stacks exceed the
combined size of ~4GB, slow down drastically in pthread_create() - because
glibc uses MAP_32BIT to allocate the stacks. The use of MAP_32BIT is
a legacy hack - to speed up context switching on certain early model
64-bit P4 CPUs.
So introduce a new flag to be used by glibc instead, to not constrain
64-bit apps like this.
glibc can switch to this new flag straight away - it will be ignored
by the kernel. If those old CPUs ever matter to anyone, support for
it can be implemented.
Signed-off-by: Ingo Molnar <[email protected]>
Acked-by: Ulrich Drepper <[email protected]>
Diffstat (limited to 'lib/debugobjects.c')
0 files changed, 0 insertions, 0 deletions