Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / block / zram / zram_drv.h

diff --git a/kernel/drivers/block/zram/zram_drv.h b/kernel/drivers/block/zram/zram_drv.h
new file mode 100644 (file)
index 0000000..570c598
--- /dev/null
+++ b/kernel/drivers/block/zram/zram_drv.h
@@ -0,0 +1,125 @@
+/*
+ * Compressed RAM block device
+ *
+ * Copyright (C) 2008, 2009, 2010  Nitin Gupta
+ *               2012, 2013 Minchan Kim
+ *
+ * This code is released using a dual license strategy: BSD/GPL
+ * You can choose the licence that better fits your requirements.
+ *
+ * Released under the terms of 3-clause BSD License
+ * Released under the terms of GNU General Public License Version 2.0
+ *
+ */
+
+#ifndef _ZRAM_DRV_H_
+#define _ZRAM_DRV_H_
+
+#include <linux/spinlock.h>
+#include <linux/zsmalloc.h>
+
+#include "zcomp.h"
+
+/*
+ * Some arbitrary value. This is just to catch
+ * invalid value for num_devices module parameter.
+ */
+static const unsigned max_num_devices = 32;
+
+/*-- Configurable parameters */
+
+/*
+ * Pages that compress to size greater than this are stored
+ * uncompressed in memory.
+ */
+static const size_t max_zpage_size = PAGE_SIZE / 4 * 3;
+
+/*
+ * NOTE: max_zpage_size must be less than or equal to:
+ *   ZS_MAX_ALLOC_SIZE. Otherwise, zs_malloc() would
+ * always return failure.
+ */
+
+/*-- End of configurable params */
+
+#define SECTOR_SHIFT           9
+#define SECTORS_PER_PAGE_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
+#define SECTORS_PER_PAGE       (1 << SECTORS_PER_PAGE_SHIFT)
+#define ZRAM_LOGICAL_BLOCK_SHIFT 12
+#define ZRAM_LOGICAL_BLOCK_SIZE        (1 << ZRAM_LOGICAL_BLOCK_SHIFT)
+#define ZRAM_SECTOR_PER_LOGICAL_BLOCK  \
+       (1 << (ZRAM_LOGICAL_BLOCK_SHIFT - SECTOR_SHIFT))
+
+
+/*
+ * 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_FLAG_SHIFT,
+       ZRAM_ACCESS,    /* page is now accessed */
+
+       __NR_ZRAM_PAGEFLAGS,
+};
+
+/*-- Data structures */
+
+/* Allocated for each disk page */
+struct zram_table_entry {
+       unsigned long handle;
+       unsigned long value;
+};
+
+struct zram_stats {
+       atomic64_t compr_data_size;     /* compressed size of pages stored */
+       atomic64_t num_reads;   /* failed + successful */
+       atomic64_t num_writes;  /* --do-- */
+       atomic64_t num_migrated;        /* no. of migrated object */
+       atomic64_t failed_reads;        /* can happen when memory is too low */
+       atomic64_t failed_writes;       /* can happen when memory is too low */
+       atomic64_t invalid_io;  /* non-page-aligned I/O requests */
+       atomic64_t notify_free; /* no. of swap slot free notifications */
+       atomic64_t zero_pages;          /* no. of zero filled pages */
+       atomic64_t pages_stored;        /* no. of pages currently stored */
+       atomic_long_t max_used_pages;   /* no. of maximum pages stored */
+};
+
+struct zram_meta {
+       struct zram_table_entry *table;
+       struct zs_pool *mem_pool;
+};
+
+struct zram {
+       struct zram_meta *meta;
+       struct zcomp *comp;
+       struct gendisk *disk;
+       /* Prevent concurrent execution of device init */
+       struct rw_semaphore init_lock;
+       /*
+        * the number of pages zram can consume for storing compressed data
+        */
+       unsigned long limit_pages;
+       int max_comp_streams;
+
+       struct zram_stats stats;
+       atomic_t refcount; /* refcount for zram_meta */
+       /* wait all IO under all of cpu are done */
+       wait_queue_head_t io_done;
+       /*
+        * This is the limit on amount of *uncompressed* worth of data
+        * we can store in a disk.
+        */
+       u64 disksize;   /* bytes */
+       char compressor[10];
+};
+#endif