From: Atish Patra <atish.patra@wdc.com>
To: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>,
Albert Ou <aou@eecs.berkeley.edu>,
Thomas Gleixner <tglx@linutronix.de>,
Kees Cook <keescook@chromium.org>,
Changbin Du <changbin.du@intel.com>,
Anup Patel <anup@brainfault.org>,
Palmer Dabbelt <palmer@sifive.com>,
"maintainer:X86 ARCHITECTURE 32-BIT AND 64-BIT" <x86@kernel.org>,
linux-mm@kvack.org, Atish Patra <atish.patra@wdc.com>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Vlastimil Babka <vbabka@suse.cz>, Gary Guo <gary@garyguo.net>,
"H. Peter Anvin" <hpa@zytor.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-riscv@lists.infradead.org,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Subject: [PATCH v2 1/3] x86: Move DEBUG_TLBFLUSH option.
Date: Mon, 29 Apr 2019 12:57:57 -0700 [thread overview]
Message-ID: <20190429195759.18330-2-atish.patra@wdc.com> (raw)
In-Reply-To: <20190429195759.18330-1-atish.patra@wdc.com>
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complicated, out-of-date, buggy TLB flushing")'.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(-)
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.
--
2.21.0
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next prev parent reply other threads:[~2019-04-29 19:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-29 19:57 [PATCH v2 0/3] TLB flush counters Atish Patra
2019-04-29 19:57 ` Atish Patra [this message]
2019-04-29 20:05 ` [PATCH v2 1/3] x86: Move DEBUG_TLBFLUSH option Ingo Molnar
2019-04-29 21:29 ` Atish Patra
2019-04-29 19:57 ` [PATCH v2 2/3] RISC-V: Enable TLBFLUSH counters for debug kernel Atish Patra
2019-04-29 19:57 ` [PATCH v2 3/3] RISC-V: Update tlb flush counters Atish Patra
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