Commit fb0328e2 authored by Nick Piggin's avatar Nick Piggin Committed by Ingo Molnar
Browse files

x86: reduce CONFIG_X86_PPRO_FENCE bloat 



CONFIG_X86_PPRO_FENCE bloats text:

i386 allmodconf: size mm/built-in.o
           text    data     bss     dec     hex         text ratio
vanilla: 163082   20372   40120  223574   36956          100.00%
bugfix : 163509   20372   40120  224001   36b01            0.26%
noppro : 162191   20372   40120  222683   365db         -  0.55%
both   : 162267   20372   40120  222759   36627         -  0.50% (+0.05% vs noppro)

So with the ppro memory ordering bug out of the way, the PG_uptodate fix
only adds 76 bytes of text.

allow this config to be specified by distros.

[ mingo@elte.hu: x86.git merge ]

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 583d0e90

arch/x86/Kconfig.cpu

+10 −1
Original line number Diff line number Diff line
@@ -321,8 +321,17 @@ config X86_XADD 
	depends on X86_32 && !M386



config X86_PPRO_FENCE

	def_bool y

	bool "PentiumPro memory ordering errata workaround"

	depends on M686 || M586MMX || M586TSC || M586 || M486 || M386 || MGEODEGX1

	help

	  Old PentiumPro multiprocessor systems had errata that could cause memory

	  operations to violate the x86 ordering standard in rare cases. Enabling this

	  option will attempt to work around some (but not all) occurances of

	  this problem, at the cost of much heavier spinlock and memory barrier

	  operations.



	  If unsure, say n here. Even distro kernels should think twice before enabling

	  this: there are few systems, and an unlikely bug.



config X86_F00F_BUG

	def_bool y

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