thp, x86: introduce HAVE_ARCH_TRANSPARENT_HUGEPAGE

Cleanup patch in preparation for transparent hugepage support on s390.
Adding new architectures to the TRANSPARENT_HUGEPAGE config option can
make the "depends" line rather ugly, like "depends on (X86 || (S390 &&
64BIT)) && MMU".

This patch adds a HAVE_ARCH_TRANSPARENT_HUGEPAGE instead.  x86 already has
MMU "def_bool y", so the MMU check is superfluous there and
HAVE_ARCH_TRANSPARENT_HUGEPAGE can be selected in arch/x86/Kconfig.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/Kconfig b/arch/Kconfig
index d5176b861e32c4278bbfa09b1ddfcc0fa090fe41..3210fc8835d4698f0f86c1c85c31a01a8681513d 100644 (file)
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -326,4 +326,7 @@ config HAVE_RCU_USER_QS
          are already protected inside rcu_irq_enter/rcu_irq_exit() but
          preemption or signal handling on irq exit still need to be protected.
 
+config HAVE_ARCH_TRANSPARENT_HUGEPAGE
+       bool
+
 source "kernel/gcov/Kconfig"

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b9aeeb3868353d22b70ae691e2bb5201245af1fb..be7515f54d67530ca1d0788ec5846a322ebbdc5a 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -85,6 +85,7 @@ config X86
        select IRQ_FORCED_THREADING
        select USE_GENERIC_SMP_HELPERS if SMP
        select HAVE_BPF_JIT if X86_64
+       select HAVE_ARCH_TRANSPARENT_HUGEPAGE
        select CLKEVT_I8253
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
        select GENERIC_IOMAP

diff --git a/mm/Kconfig b/mm/Kconfig
index d5c8019c662793886224b872cc494e1ae3d00842..3322342a1ffb0796708e2045571472235e502927 100644 (file)
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -318,7 +318,7 @@ config NOMMU_INITIAL_TRIM_EXCESS
 
 config TRANSPARENT_HUGEPAGE
        bool "Transparent Hugepage Support"
-       depends on X86 && MMU
+       depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE
        select COMPACTION
        help
          Transparent Hugepages allows the kernel to use huge pages and