diff options
| author | Ingo Molnar <mingo@elte.hu> | 2008-08-13 18:02:18 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-08-15 11:45:19 -0700 |
| commit | cd98a04a59e2f94fa64d5bf1e26498d27427d5e7 (patch) | |
| tree | a6e9c7996612e52eb4ac2dc0d03046120965efc1 /drivers/dma/ioat.c | |
| parent | 45edb89ffd6386f95a7a9e1e5461b0e61c76aa14 (diff) | |
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 <mingo@elte.hu>
Acked-by: Ulrich Drepper <drepper@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/dma/ioat.c')
0 files changed, 0 insertions, 0 deletions