diff options
| author | Vineet Gupta <Vineet.Gupta1@synopsys.com> | 2019-11-30 17:51:06 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-12-01 06:29:19 -0800 |
| commit | 6aae3425aa9ca776e8201a93494a4a482353d2c3 (patch) | |
| tree | 92a2ea5d629f3f56c6fde9d5f04e3c2581166f79 /arch/arc | |
| parent | ff68dac6d65cd1347dad5d780dd8c90f29dc1b0b (diff) | |
ARC: mm: remove __ARCH_USE_5LEVEL_HACK
Patch series "elide extraneous generated code for folded p4d/pud/pmd", v3.
This series came out of seemingly benign excursion into
understanding/removing __ARCH_USE_5LEVEL_HACK from ARC port showing some
extraneous code being generated despite folded p4d/pud/pmd
| bloat-o-meter2 vmlinux-[AB]*
| add/remove: 0/0 grow/shrink: 3/0 up/down: 130/0 (130)
| function old new delta
| free_pgd_range 548 660 +112
| p4d_clear_bad 2 20 +18
The patches here address that
| bloat-o-meter2 vmlinux-[BF]*
| add/remove: 0/2 grow/shrink: 0/1 up/down: 0/-386 (-386)
| function old new delta
| pud_clear_bad 20 - -20
| p4d_clear_bad 20 - -20
| free_pgd_range 660 314 -346
The code savings are not a whole lot, but still worthwhile IMHO.
This patch (of 5):
With paging code made 5-level compliant, this is no longer needed. ARC
has software page walker with 2 lookup levels (pgd -> pte)
This was expected to be non functional change but ended with slight
code bloat due to needless inclusions of p*d_free_tlb() macros which
will be addressed in further patches.
| bloat-o-meter2 vmlinux-[AB]*
| add/remove: 0/0 grow/shrink: 2/0 up/down: 128/0 (128)
| function old new delta
| free_pgd_range 546 656 +110
| p4d_clear_bad 2 20 +18
| Total: Before=4137148, After=4137276, chg 0.000000%
Link: http://lkml.kernel.org/r/20191016162400.14796-2-vgupta@synopsys.com
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/arc')
| -rw-r--r-- | arch/arc/include/asm/pgtable.h | 1 | ||||
| -rw-r--r-- | arch/arc/mm/fault.c | 10 | ||||
| -rw-r--r-- | arch/arc/mm/highmem.c | 4 |
3 files changed, 11 insertions, 4 deletions
diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h index 7addd0301c51..b917b596f7fb 100644 --- a/arch/arc/include/asm/pgtable.h +++ b/arch/arc/include/asm/pgtable.h @@ -33,7 +33,6 @@ #define _ASM_ARC_PGTABLE_H #include <linux/bits.h> -#define __ARCH_USE_5LEVEL_HACK #include <asm-generic/pgtable-nopmd.h> #include <asm/page.h> #include <asm/mmu.h> /* to propagate CONFIG_ARC_MMU_VER <n> */ diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c index 3861543b66a0..fb86bc3e9b35 100644 --- a/arch/arc/mm/fault.c +++ b/arch/arc/mm/fault.c @@ -30,6 +30,7 @@ noinline static int handle_kernel_vaddr_fault(unsigned long address) * with the 'reference' page table. */ pgd_t *pgd, *pgd_k; + p4d_t *p4d, *p4d_k; pud_t *pud, *pud_k; pmd_t *pmd, *pmd_k; @@ -39,8 +40,13 @@ noinline static int handle_kernel_vaddr_fault(unsigned long address) if (!pgd_present(*pgd_k)) goto bad_area; - pud = pud_offset(pgd, address); - pud_k = pud_offset(pgd_k, address); + p4d = p4d_offset(pgd, address); + p4d_k = p4d_offset(pgd_k, address); + if (!p4d_present(*p4d_k)) + goto bad_area; + + pud = pud_offset(p4d, address); + pud_k = pud_offset(p4d_k, address); if (!pud_present(*pud_k)) goto bad_area; diff --git a/arch/arc/mm/highmem.c b/arch/arc/mm/highmem.c index a4856bfaedf3..fc8849e4f72e 100644 --- a/arch/arc/mm/highmem.c +++ b/arch/arc/mm/highmem.c @@ -111,12 +111,14 @@ EXPORT_SYMBOL(__kunmap_atomic); static noinline pte_t * __init alloc_kmap_pgtable(unsigned long kvaddr) { pgd_t *pgd_k; + p4d_t *p4d_k; pud_t *pud_k; pmd_t *pmd_k; pte_t *pte_k; pgd_k = pgd_offset_k(kvaddr); - pud_k = pud_offset(pgd_k, kvaddr); + p4d_k = p4d_offset(pgd_k, kvaddr); + pud_k = pud_offset(p4d_k, kvaddr); pmd_k = pmd_offset(pud_k, kvaddr); pte_k = (pte_t *)memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); |