| Message ID | 20190429195759.18330-2-atish.patra@wdc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | TLB flush counters | expand |
* Atish Patra <atish.patra@wdc.com> wrote: > CONFIG_DEBUG_TLBFLUSH was added in 'commit 3df3212f9722 ("x86/tlb: add > tlb_flushall_shift knob into debugfs")' to support tlb_flushall_shift > knob. The knob was removed in 'commit e9f4e0a9fe27 ("x86/mm: Rip out > complicated, out-of-date, buggy TLB flushing")'. However, the debug > option was never removed from Kconfig. It was reused in commit > '9824cf9753ec ("mm: vmstats: tlb flush counters")' but the commit text > was never updated accordingly. Please, when you mention several commits, put them into new lines to make it readable, i.e.: 3df3212f9722 ("x86/tlb: add tlb_flushall_shift knob into debugfs") etc. > Update the Kconfig option description as per its current usage. > > Take this opprtunity to make this kconfig option a common option as it > touches the common vmstat code. Introduce another arch specific config > HAVE_ARCH_DEBUG_TLBFLUSH that can be selected to enable this config. "opprtunity"? > +config HAVE_ARCH_DEBUG_TLBFLUSH > + bool > + depends on DEBUG_KERNEL > + > +config DEBUG_TLBFLUSH > + bool "Save tlb flush statstics to vmstat" > + depends on HAVE_ARCH_DEBUG_TLBFLUSH > + help > + > + Add tlbflush statstics to vmstat. It is really helpful understand tlbflush > + performance and behavior. It should be enabled only for debugging purpose > + by individual architectures explicitly by selecting HAVE_ARCH_DEBUG_TLBFLUSH. "statstics"?? Please put a spell checker into your workflow or read what you are writing ... Thanks, Ingo
On 4/29/19 1:06 PM, Ingo Molnar wrote: > > * Atish Patra <atish.patra@wdc.com> wrote: > >> CONFIG_DEBUG_TLBFLUSH was added in 'commit 3df3212f9722 ("x86/tlb: add >> tlb_flushall_shift knob into debugfs")' to support tlb_flushall_shift >> knob. The knob was removed in 'commit e9f4e0a9fe27 ("x86/mm: Rip out >> complicated, out-of-date, buggy TLB flushing")'. However, the debug >> option was never removed from Kconfig. It was reused in commit >> '9824cf9753ec ("mm: vmstats: tlb flush counters")' but the commit text >> was never updated accordingly. > > Please, when you mention several commits, put them into new lines to make > it readable, i.e.: > > 3df3212f9722 ("x86/tlb: add tlb_flushall_shift knob into debugfs") > > etc. > Done. >> Update the Kconfig option description as per its current usage. >> >> Take this opprtunity to make this kconfig option a common option as it >> touches the common vmstat code. Introduce another arch specific config >> HAVE_ARCH_DEBUG_TLBFLUSH that can be selected to enable this config. > > "opprtunity"? > >> +config HAVE_ARCH_DEBUG_TLBFLUSH >> + bool >> + depends on DEBUG_KERNEL >> + >> +config DEBUG_TLBFLUSH >> + bool "Save tlb flush statstics to vmstat" >> + depends on HAVE_ARCH_DEBUG_TLBFLUSH >> + help >> + >> + Add tlbflush statstics to vmstat. It is really helpful understand tlbflush >> + performance and behavior. It should be enabled only for debugging purpose >> + by individual architectures explicitly by selecting HAVE_ARCH_DEBUG_TLBFLUSH. > > "statstics"?? > > Please put a spell checker into your workflow or read what you are > writing ... > Apologies for the typos. Fixed them. Regards, Atish > Thanks, > > Ingo >
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 62fc3fda1a05..4c59f59e9491 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -132,6 +132,7 @@ config X86 select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if X86_64 select HAVE_ARCH_VMAP_STACK if X86_64 select HAVE_ARCH_WITHIN_STACK_FRAMES + select HAVE_ARCH_DEBUG_TLBFLUSH if DEBUG_KERNEL select HAVE_CMPXCHG_DOUBLE select HAVE_CMPXCHG_LOCAL select HAVE_CONTEXT_TRACKING if X86_64 diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 15d0fbe27872..0c8f9931e901 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -124,25 +124,6 @@ config DOUBLEFAULT option saves about 4k and might cause you much additional grey hair. -config DEBUG_TLBFLUSH - bool "Set upper limit of TLB entries to flush one-by-one" - depends on DEBUG_KERNEL - ---help--- - - 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: - - flush_entries <= active_tlb_entries / 2^tlb_flushall_shift - - If in doubt, say "N". - config IOMMU_DEBUG bool "Enable IOMMU debugging" depends on GART_IOMMU && DEBUG_KERNEL diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug index e3df921208c0..760c3fda8b57 100644 --- a/mm/Kconfig.debug +++ b/mm/Kconfig.debug @@ -111,3 +111,16 @@ config DEBUG_RODATA_TEST depends on STRICT_KERNEL_RWX ---help--- This option enables a testcase for the setting rodata read-only. + +config HAVE_ARCH_DEBUG_TLBFLUSH + bool + depends on DEBUG_KERNEL + +config DEBUG_TLBFLUSH + bool "Save tlb flush statstics to vmstat" + depends on HAVE_ARCH_DEBUG_TLBFLUSH + help + + Add tlbflush statstics to vmstat. It is really helpful understand tlbflush + performance and behavior. It should be enabled only for debugging purpose + by individual architectures explicitly by selecting HAVE_ARCH_DEBUG_TLBFLUSH.
CONFIG_DEBUG_TLBFLUSH was added in 'commit 3df3212f9722 ("x86/tlb: add tlb_flushall_shift knob into debugfs")' to support tlb_flushall_shift knob. The knob was removed in 'commit e9f4e0a9fe27 ("x86/mm: Rip out complicated, out-of-date, buggy TLB flushing")'. However, the debug option was never removed from Kconfig. It was reused in commit '9824cf9753ec ("mm: vmstats: tlb flush counters")' but the commit text was never updated accordingly. Update the Kconfig option description as per its current usage. Take this opprtunity to make this kconfig option a common option as it touches the common vmstat code. Introduce another arch specific config HAVE_ARCH_DEBUG_TLBFLUSH that can be selected to enable this config. Signed-off-by: Atish Patra <atish.patra@wdc.com> --- arch/x86/Kconfig | 1 + arch/x86/Kconfig.debug | 19 ------------------- mm/Kconfig.debug | 13 +++++++++++++ 3 files changed, 14 insertions(+), 19 deletions(-)