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path: root/drivers/block/zram/zram_drv.h
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Diffstat (limited to 'drivers/block/zram/zram_drv.h')
-rw-r--r--drivers/block/zram/zram_drv.h24
1 files changed, 18 insertions, 6 deletions
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index c8161bd8969c..5b0afde729cd 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -50,10 +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,
};
@@ -63,9 +77,8 @@ enum zram_pageflags {
/* Allocated for each disk page */
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 */
@@ -80,7 +93,6 @@ struct zram_stats {
};
struct zram_meta {
- rwlock_t tb_lock; /* protect table */
struct zram_table_entry *table;
struct zs_pool *mem_pool;
};