diff options
Diffstat (limited to 'drivers/block/zram/zram_drv.h')
| -rw-r--r-- | drivers/block/zram/zram_drv.h | 29 |
1 files changed, 20 insertions, 9 deletions
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h index 7f21c145e317..5b0afde729cd 100644 --- a/drivers/block/zram/zram_drv.h +++ b/drivers/block/zram/zram_drv.h @@ -43,7 +43,6 @@ static const size_t max_zpage_size = PAGE_SIZE / 4 * 3; /*-- End of configurable params */ #define SECTOR_SHIFT 9 -#define SECTOR_SIZE (1 << SECTOR_SHIFT) #define SECTORS_PER_PAGE_SHIFT (PAGE_SHIFT - SECTOR_SHIFT) #define SECTORS_PER_PAGE (1 << SECTORS_PER_PAGE_SHIFT) #define ZRAM_LOGICAL_BLOCK_SHIFT 12 @@ -51,10 +50,24 @@ static const size_t max_zpage_size = PAGE_SIZE / 4 * 3; #define ZRAM_SECTOR_PER_LOGICAL_BLOCK \ (1 << (ZRAM_LOGICAL_BLOCK_SHIFT - SECTOR_SHIFT)) -/* Flags for zram pages (table[page_no].flags) */ + +/* + * The lower ZRAM_FLAG_SHIFT bits of table.value is for + * object size (excluding header), the higher bits is for + * zram_pageflags. + * + * zram is mainly used for memory efficiency so we want to keep memory + * footprint small so we can squeeze size and flags into a field. + * The lower ZRAM_FLAG_SHIFT bits is for object size (excluding header), + * the higher bits is for zram_pageflags. + */ +#define ZRAM_FLAG_SHIFT 24 + +/* Flags for zram pages (table[page_no].value) */ enum zram_pageflags { /* Page consists entirely of zeros */ - ZRAM_ZERO, + ZRAM_ZERO = ZRAM_FLAG_SHIFT + 1, + ZRAM_ACCESS, /* page in now accessed */ __NR_ZRAM_PAGEFLAGS, }; @@ -62,11 +75,10 @@ enum zram_pageflags { /*-- Data structures */ /* Allocated for each disk page */ -struct table { +struct zram_table_entry { unsigned long handle; - u16 size; /* object size (excluding header) */ - u8 flags; -} __aligned(4); + unsigned long value; +}; struct zram_stats { atomic64_t compr_data_size; /* compressed size of pages stored */ @@ -81,8 +93,7 @@ struct zram_stats { }; struct zram_meta { - rwlock_t tb_lock; /* protect table */ - struct table *table; + struct zram_table_entry *table; struct zs_pool *mem_pool; }; |