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Commit d195b71b authored by David S. Miller's avatar David S. Miller
Browse files

sparc64: Kill unnecessary tables and increase MAX_BANKS. 



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: default avatarDavid S. Miller <davem@davemloft.net>
Acked-by: default avatarBob Picco <bob.picco@oracle.com>
parent ee6a9333

arch/sparc/include/asm/pgtable_64.h

+0 −1
Original line number Diff line number Diff line
@@ -927,7 +927,6 @@ static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr, 
#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);

arch/sparc/kernel/vmlinux.lds.S

+3 −2
Original line number Diff line number Diff line
@@ -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 :

	{

arch/sparc/mm/init_64.c

+2 −23
Original line number Diff line number Diff line
@@ -87,7 +87,7 @@ extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES]; 


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_finalize(void) 


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);
@@ -2002,8 +1996,6 @@ 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();
@@ -2099,20 +2091,7 @@ 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();