xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

powerpc/64s/radix: Enable HAVE_ARCH_HUGE_VMAP

Browse Source 
This sets the HAVE_ARCH_HUGE_VMAP option, and defines the required
page table functions.

This enables huge (2MB and 1GB) ioremap mappings. I don't have a
benchmark for this change, but huge vmap will be used by a later core
kernel change to enable huge vmalloc memory mappings. This improves
cached `git diff` performance by about 5% on a 2-node POWER9 with 32MB
size dentry cache hash.

  Profiling git diff dTLB misses with a vanilla kernel:

  81.75%  git      [kernel.vmlinux]    [k] __d_lookup_rcu
   7.21%  git      [kernel.vmlinux]    [k] strncpy_from_user
   1.77%  git      [kernel.vmlinux]    [k] find_get_entry
   1.59%  git      [kernel.vmlinux]    [k] kmem_cache_free

            40,168      dTLB-miss
       0.100342754 seconds time elapsed

  With powerpc huge vmalloc:

             2,987      dTLB-miss
       0.095933138 seconds time elapsed

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin
2019-06-10 13:08:18 +10:00
committed by Michael Ellerman
parent d38153f9cc
commit d909f9109c
4 changed files with 110 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
arch/powerpc/include/asm/book3s/64/pgtable.h
View File

@@ -274,6 +274,14 @@ extern unsigned long __vmalloc_end;
#define VMALLOC_START __vmalloc_start
#define VMALLOC_END __vmalloc_end
static inline unsigned int ioremap_max_order(void)
{
if (radix_enabled())
return PUD_SHIFT;
return 7 + PAGE_SHIFT; /* default from linux/vmalloc.h */
}
#define IOREMAP_MAX_ORDER ioremap_max_order()
extern unsigned long __kernel_virt_start;
extern unsigned long __kernel_virt_size;
extern unsigned long __kernel_io_start;