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| author | Catalin Marinas <catalin.marinas@arm.com> | 2014-10-10 15:37:28 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2014-10-20 17:47:02 +0100 |
| commit | 2a0b5c0d19298cad54573682321b5fe015fa5a0d (patch) | |
| tree | d1b64ac1f1ce289bb1184fa4563930a2be9519e8 /arch/arm64 | |
| parent | 04f905a9569ca2b6964a35563f135fabbb2470bc (diff) | |
| download | linux-2a0b5c0d19298cad54573682321b5fe015fa5a0d.tar.gz | |
arm64: Align less than PAGE_SIZE pgds naturally
When the pgd size is smaller than PAGE_SIZE, pgd_alloc() uses kzalloc() to save space. However, this is not always naturally aligned as required by the architecture. This patch creates a kmem_cache for pgd allocations with the correct alignment. The current kernel configurations with 4K pages + 39-bit VA and 64K pages + 42-bit VA use a full page for the pgd and are not affected. The patch is required for 48-bit VA with 64K pages where the pgd is 512 bytes. Reported-by: Christoffer Dall <christoffer.dall@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/mm/pgd.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/arch/arm64/mm/pgd.c b/arch/arm64/mm/pgd.c index 62c6101df260..6682b361d3ac 100644 --- a/arch/arm64/mm/pgd.c +++ b/arch/arm64/mm/pgd.c @@ -30,12 +30,14 @@ #define PGD_SIZE (PTRS_PER_PGD * sizeof(pgd_t)) +static struct kmem_cache *pgd_cache; + pgd_t *pgd_alloc(struct mm_struct *mm) { if (PGD_SIZE == PAGE_SIZE) return (pgd_t *)get_zeroed_page(GFP_KERNEL); else - return kzalloc(PGD_SIZE, GFP_KERNEL); + return kmem_cache_zalloc(pgd_cache, GFP_KERNEL); } void pgd_free(struct mm_struct *mm, pgd_t *pgd) @@ -43,5 +45,17 @@ void pgd_free(struct mm_struct *mm, pgd_t *pgd) if (PGD_SIZE == PAGE_SIZE) free_page((unsigned long)pgd); else - kfree(pgd); + kmem_cache_free(pgd_cache, pgd); +} + +static int __init pgd_cache_init(void) +{ + /* + * Naturally aligned pgds required by the architecture. + */ + if (PGD_SIZE != PAGE_SIZE) + pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_SIZE, + SLAB_PANIC, NULL); + return 0; } +core_initcall(pgd_cache_init); |