Le 02/05/2021 à 06:56, Nicholas Piggin a écrit :
This reduces TLB misses by nearly 30x on a `git diff` workload on a
2-node POWER9 (59,800 -> 2,100) and reduces CPU cycles by 0.54%, due
to vfs hashes being allocated with 2MB pages.
Acked-by: Michael Ellerman <m...@ellerman.id.au>
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
---
This was in the -mm tree but was dropped at the last minute after
clashing with a patch in powerpc next.
Now all prerequisites are upstream, this can be merged as is. Probably
makes sense now to go via powerpc tree.
This is rebased and retested on upstream.
Documentation/admin-guide/kernel-parameters.txt | 2 ++
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/pgtable.h | 5 +++++
arch/powerpc/kernel/module.c | 16 +++++++++++++---
4 files changed, 21 insertions(+), 3 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt
b/Documentation/admin-guide/kernel-parameters.txt
index 1c0a3cf6fcc9..1be38b25c485 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3250,6 +3250,8 @@
nohugeiomap [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings.
+ nohugevmalloc [PPC] Disable kernel huge vmalloc mappings.
+
nosmt [KNL,S390] Disable symmetric multithreading (SMT).
Equivalent to smt=1.
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 1e6230bea09d..c547a9d6a2dd 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -185,6 +185,7 @@ config PPC
select GENERIC_VDSO_TIME_NS
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ARCH_HUGE_VMAP if PPC_BOOK3S_64 &&
PPC_RADIX_MMU
+ select HAVE_ARCH_HUGE_VMALLOC if HAVE_ARCH_HUGE_VMAP
select HAVE_ARCH_JUMP_LABEL
select HAVE_ARCH_JUMP_LABEL_RELATIVE
select HAVE_ARCH_KASAN if PPC32 && PPC_PAGE_SHIFT <= 14
diff --git a/arch/powerpc/include/asm/pgtable.h
b/arch/powerpc/include/asm/pgtable.h
index c6a676714f04..1678e4b08fc3 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -39,6 +39,11 @@ struct mm_struct;
#define __S110 PAGE_SHARED_X
#define __S111 PAGE_SHARED_X
+#ifndef MODULES_VADDR
+#define MODULES_VADDR VMALLOC_START
+#define MODULES_END VMALLOC_END
+#endif
This will also require some changes in a few places, see
https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20210429031602.2606654-4-jniet...@gmail.com/
+
#ifndef __ASSEMBLY__
/* Keep these as a macros to avoid include dependency mess */
diff --git a/arch/powerpc/kernel/module.c b/arch/powerpc/kernel/module.c
index fab84024650c..77aefcbbd276 100644
--- a/arch/powerpc/kernel/module.c
+++ b/arch/powerpc/kernel/module.c
@@ -8,6 +8,7 @@
#include <linux/moduleloader.h>
#include <linux/err.h>
#include <linux/vmalloc.h>
+#include <linux/mm.h>
#include <linux/bug.h>
#include <asm/module.h>
#include <linux/uaccess.h>
@@ -88,17 +89,24 @@ int module_finalize(const Elf_Ehdr *hdr,
return 0;
}
-#ifdef MODULES_VADDR
static __always_inline void *
__module_alloc(unsigned long size, unsigned long start, unsigned long end)
{
+ /*
+ * Don't do huge page allocations for modules yet until more testing
+ * is done. STRICT_MODULE_RWX may require extra work to support this
+ * too.
+ */
return __vmalloc_node_range(size, 1, start, end, GFP_KERNEL,
- PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS,
NUMA_NO_NODE,
+ PAGE_KERNEL_EXEC,
+ VM_FLUSH_RESET_PERMS | VM_NO_HUGE_VMAP,
+ NUMA_NO_NODE,
__builtin_return_address(0));
Can we avoid so many lines ? Doesn't it fit on 3 lines now that 100 chars per
line are tolerated ?
}
void *module_alloc(unsigned long size)
{
+#ifdef CONFIG_PPC32
Can we just add an IS_ENABLED(CONFIG_PPC32) in the 'if' instead of this
#ifdef/#else ?
unsigned long limit = (unsigned long)_etext - SZ_32M;
void *ptr = NULL;
@@ -112,5 +120,7 @@ void *module_alloc(unsigned long size)
ptr = __module_alloc(size, MODULES_VADDR, MODULES_END);
return ptr;
-}
+#else
+ return __module_alloc(size, MODULES_VADDR, MODULES_END);
#endif
+}
