diff options
| -rw-r--r-- | arch/s390/mm/vmem.c | 45 |
1 files changed, 42 insertions, 3 deletions
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c index df361bbacda1..70ebfc7958a6 100644 --- a/arch/s390/mm/vmem.c +++ b/arch/s390/mm/vmem.c @@ -74,7 +74,22 @@ static void vmem_pte_free(unsigned long *table) #define PAGE_UNUSED 0xFD -static void vmemmap_use_sub_pmd(unsigned long start, unsigned long end) +/* + * The unused vmemmap range, which was not yet memset(PAGE_UNUSED) ranges + * from unused_pmd_start to next PMD_SIZE boundary. + */ +static unsigned long unused_pmd_start; + +static void vmemmap_flush_unused_pmd(void) +{ + if (!unused_pmd_start) + return; + memset(__va(unused_pmd_start), PAGE_UNUSED, + ALIGN(unused_pmd_start, PMD_SIZE) - unused_pmd_start); + unused_pmd_start = 0; +} + +static void __vmemmap_use_sub_pmd(unsigned long start, unsigned long end) { /* * As we expect to add in the same granularity as we remove, it's @@ -85,18 +100,41 @@ static void vmemmap_use_sub_pmd(unsigned long start, unsigned long end) memset(__va(start), 0, sizeof(struct page)); } +static void vmemmap_use_sub_pmd(unsigned long start, unsigned long end) +{ + /* + * We only optimize if the new used range directly follows the + * previously unused range (esp., when populating consecutive sections). + */ + if (unused_pmd_start == start) { + unused_pmd_start = end; + if (likely(IS_ALIGNED(unused_pmd_start, PMD_SIZE))) + unused_pmd_start = 0; + return; + } + vmemmap_flush_unused_pmd(); + __vmemmap_use_sub_pmd(start, end); +} + static void vmemmap_use_new_sub_pmd(unsigned long start, unsigned long end) { void *page = __va(ALIGN_DOWN(start, PMD_SIZE)); + vmemmap_flush_unused_pmd(); + /* Could be our memmap page is filled with PAGE_UNUSED already ... */ - vmemmap_use_sub_pmd(start, end); + __vmemmap_use_sub_pmd(start, end); /* Mark the unused parts of the new memmap page PAGE_UNUSED. */ if (!IS_ALIGNED(start, PMD_SIZE)) memset(page, PAGE_UNUSED, start - __pa(page)); + /* + * We want to avoid memset(PAGE_UNUSED) when populating the vmemmap of + * consecutive sections. Remember for the last added PMD the last + * unused range in the populated PMD. + */ if (!IS_ALIGNED(end, PMD_SIZE)) - memset(__va(end), PAGE_UNUSED, __pa(page) + PMD_SIZE - end); + unused_pmd_start = end; } /* Returns true if the PMD is completely unused and can be freed. */ @@ -104,6 +142,7 @@ static bool vmemmap_unuse_sub_pmd(unsigned long start, unsigned long end) { void *page = __va(ALIGN_DOWN(start, PMD_SIZE)); + vmemmap_flush_unused_pmd(); memset(__va(start), PAGE_UNUSED, end - start); return !memchr_inv(page, PAGE_UNUSED, PMD_SIZE); } |