bool "Set upper limit of TLB entries to flush one-by-one"
depends on DEBUG_KERNEL
help
+ X86-only for now.
- X86-only for now.
+ This option allows the user to tune the amount of TLB entries the
+ kernel flushes one-by-one instead of doing a full TLB flush. In
+ certain situations, the former is cheaper. This is controlled by the
+ tlb_flushall_shift knob under /sys/kernel/debug/x86. If you set it
+ to -1, the code flushes the whole TLB unconditionally. Otherwise,
+ for positive values of it, the kernel will use single TLB entry
+ invalidating instructions according to the following formula:
- This option allows the user to tune the amount of TLB entries the
- kernel flushes one-by-one instead of doing a full TLB flush. In
- certain situations, the former is cheaper. This is controlled by the
- tlb_flushall_shift knob under /sys/kernel/debug/x86. If you set it
- to -1, the code flushes the whole TLB unconditionally. Otherwise,
- for positive values of it, the kernel will use single TLB entry
- invalidating instructions according to the following formula:
+ flush_entries <= active_tlb_entries / 2^tlb_flushall_shift
- flush_entries <= active_tlb_entries / 2^tlb_flushall_shift
-
- If in doubt, say "N".
+ If in doubt, say "N".
config IOMMU_DEBUG
bool "Enable IOMMU debugging"
depends on DEBUG_KERNEL && INSTRUCTION_DECODER
depends on !COMPILE_TEST
help
- Perform x86 instruction decoder selftests at build time.
- This option is useful for checking the sanity of x86 instruction
- decoder code.
- If unsure, say "N".
+ Perform x86 instruction decoder selftests at build time.
+ This option is useful for checking the sanity of x86 instruction
+ decoder code.
+ If unsure, say "N".
choice
prompt "IO delay type"