| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.17 143/146] sparc64: Kill unnecessary tables and increase MAX_BANKS. | Date | Tue, 28 Oct 2014 11:34:45 +0800 |
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3.17-stable review patch. If anyone has any objections, please let me know.
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From: "David S. Miller" <davem@davemloft.net>
[ Upstream commit d195b71bad4347d2df51072a537f922546a904f1 ]
swapper_low_pmd_dir and swapper_pud_dir are actually completely useless and unnecessary.
We just need swapper_pg_dir[]. Naturally the other page table chunks will be allocated on an as-needed basis. Since the kernel actually accesses these tables in the PAGE_OFFSET view, there is not even a TLB locality advantage of placing them in the kernel image.
Use the hard coded vmlinux.ld.S slot for swapper_pg_dir which is naturally page aligned.
Increase MAX_BANKS to 1024 in order to handle heavily fragmented virtual guests.
Even with this MAX_BANKS increase, the kernel is 20K+ smaller.
Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Bob Picco <bob.picco@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/sparc/include/asm/pgtable_64.h | 1 - arch/sparc/kernel/vmlinux.lds.S | 5 +++-- arch/sparc/mm/init_64.c | 25 ++----------------------- 3 files changed, 5 insertions(+), 26 deletions(-)
--- a/arch/sparc/include/asm/pgtable_64.h +++ b/arch/sparc/include/asm/pgtable_64.h @@ -927,7 +927,6 @@ static inline void __set_pte_at(struct m #endif extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; -extern pmd_t swapper_low_pmd_dir[PTRS_PER_PMD]; void paging_init(void); unsigned long find_ecache_flush_span(unsigned long size); --- a/arch/sparc/kernel/vmlinux.lds.S +++ b/arch/sparc/kernel/vmlinux.lds.S @@ -35,8 +35,9 @@ jiffies = jiffies_64; SECTIONS { - /* swapper_low_pmd_dir is sparc64 only */ - swapper_low_pmd_dir = 0x0000000000402000; +#ifdef CONFIG_SPARC64 + swapper_pg_dir = 0x0000000000402000; +#endif . = INITIAL_ADDRESS; .text TEXTSTART : { --- a/arch/sparc/mm/init_64.c +++ b/arch/sparc/mm/init_64.c @@ -87,7 +87,7 @@ extern struct tsb swapper_tsb[KERNEL_TSB static unsigned long cpu_pgsz_mask; -#define MAX_BANKS 32 +#define MAX_BANKS 1024 static struct linux_prom64_registers pavail[MAX_BANKS]; static int pavail_ents; @@ -1943,12 +1943,6 @@ static void __init sun4v_linear_pte_xor_ static unsigned long last_valid_pfn; -/* These must be page aligned in order to not trigger the - * alignment tests of pgd_bad() and pud_bad(). - */ -pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__ ((aligned (PAGE_SIZE))); -static pud_t swapper_pud_dir[PTRS_PER_PUD] __attribute__ ((aligned (PAGE_SIZE))); - static void sun4u_pgprot_init(void); static void sun4v_pgprot_init(void); @@ -1956,8 +1950,6 @@ void __init paging_init(void) { unsigned long end_pfn, shift, phys_base; unsigned long real_end, i; - pud_t *pud; - pmd_t *pmd; int node; setup_page_offset(); @@ -2052,20 +2044,7 @@ void __init paging_init(void) */ init_mm.pgd += ((shift) / (sizeof(pgd_t))); - memset(swapper_low_pmd_dir, 0, sizeof(swapper_low_pmd_dir)); - - /* The kernel page tables we publish into what the rest of the - * world sees must be adjusted so that they see the PAGE_OFFSET - * address of these in-kerenel data structures. However right - * here we must access them from the kernel image side, because - * the trap tables haven't been taken over and therefore we cannot - * take TLB misses in the PAGE_OFFSET linear mappings yet. - */ - pud = swapper_pud_dir + (shift / sizeof(pud_t)); - pgd_set(&swapper_pg_dir[0], pud); - - pmd = swapper_low_pmd_dir + (shift / sizeof(pmd_t)); - pud_set(&swapper_pud_dir[0], pmd); + memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir)); inherit_prom_mappings();
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