From: Anton Blanchard <[email protected]>
During some code inspection using gcc 4.0 I noticed a stack frame was being
created for a number of functions that didnt require it. For example:
c0000000000df944 <._spin_unlock>:
c0000000000df944: fb e1 ff f0 std r31,-16(r1)
c0000000000df948: f8 21 ff c1 stdu r1,-64(r1)
c0000000000df94c: 7c 3f 0b 78 mr r31,r1
c0000000000df950: 7c 20 04 ac lwsync
c0000000000df954: e8 21 00 00 ld r1,0(r1)
c0000000000df958: 38 00 00 00 li r0,0
c0000000000df95c: 90 03 00 00 stw r0,0(r3)
c0000000000df960: eb e1 ff f0 ld r31,-16(r1)
c0000000000df964: 4e 80 00 20 blr
It turns out we are adding -fno-omit-frame-pointer to ppc64 which is
causing the above behaviour. Removing that flag results in much better
code:
c0000000000d5b30 <._spin_unlock>:
c0000000000d5b30: 7c 20 04 ac lwsync
c0000000000d5b34: 38 00 00 00 li r0,0
c0000000000d5b38: 90 03 00 00 stw r0,0(r3)
c0000000000d5b3c: 4e 80 00 20 blr
We dont require a frame pointer to debug on ppc64, so remove it.
Signed-off-by: Anton Blanchard <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
25-akpm/arch/ppc64/Kconfig | 4 ----
1 files changed, 4 deletions(-)
diff -puN arch/ppc64/Kconfig~ppc64-remove-fno-omit-frame-pointer arch/ppc64/Kconfig
--- 25/arch/ppc64/Kconfig~ppc64-remove-fno-omit-frame-pointer 2005-04-12 03:21:16.157680560 -0700
+++ 25-akpm/arch/ppc64/Kconfig 2005-04-12 03:21:16.160680104 -0700
@@ -40,10 +40,6 @@ config COMPAT
bool
default y
-config FRAME_POINTER
- bool
- default y
-
# We optimistically allocate largepages from the VM, so make the limit
# large enough (16MB). This badly named config option is actually
# max order + 1
_
-
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