diff options
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/Kconfig | 2 | ||||
| -rw-r--r-- | drivers/block/Makefile | 1 | ||||
| -rw-r--r-- | drivers/block/zram/Kconfig | 25 | ||||
| -rw-r--r-- | drivers/block/zram/Makefile | 3 | ||||
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 1004 | ||||
| -rw-r--r-- | drivers/block/zram/zram_drv.h | 124 |
6 files changed, 1159 insertions, 0 deletions
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig index 717d6e4..b7ac932 100644 --- a/drivers/block/Kconfig +++ b/drivers/block/Kconfig @@ -116,6 +116,8 @@ config PARIDE source "drivers/block/paride/Kconfig" +source "drivers/block/zram/Kconfig" + config BLK_CPQ_DA tristate "Compaq SMART2 support" depends on PCI && VIRT_TO_BUS diff --git a/drivers/block/Makefile b/drivers/block/Makefile index 76646e9..edc9543 100644 --- a/drivers/block/Makefile +++ b/drivers/block/Makefile @@ -40,4 +40,5 @@ obj-$(CONFIG_XEN_BLKDEV_BACKEND) += xen-blkback/ obj-$(CONFIG_BLK_DEV_DRBD) += drbd/ obj-$(CONFIG_BLK_DEV_RBD) += rbd.o +obj-$(CONFIG_ZRAM) += zram/ swim_mod-y := swim.o swim_asm.o diff --git a/drivers/block/zram/Kconfig b/drivers/block/zram/Kconfig new file mode 100644 index 0000000..983314c --- /dev/null +++ b/drivers/block/zram/Kconfig @@ -0,0 +1,25 @@ +config ZRAM + tristate "Compressed RAM block device support" + depends on BLOCK && SYSFS && ZSMALLOC + select LZO_COMPRESS + select LZO_DECOMPRESS + default n + help + Creates virtual block devices called /dev/zramX (X = 0, 1, ...). + Pages written to these disks are compressed and stored in memory + itself. These disks allow very fast I/O and compression provides + good amounts of memory savings. + + It has several use cases, for example: /tmp storage, use as swap + disks and maybe many more. + + See zram.txt for more information. + Project home: <https://compcache.googlecode.com/> + +config ZRAM_DEBUG + bool "Compressed RAM block device debug support" + depends on ZRAM + default n + help + This option adds additional debugging code to the compressed + RAM block device driver. diff --git a/drivers/block/zram/Makefile b/drivers/block/zram/Makefile new file mode 100644 index 0000000..cb0f9ce --- /dev/null +++ b/drivers/block/zram/Makefile @@ -0,0 +1,3 @@ +zram-y := zram_drv.o + +obj-$(CONFIG_ZRAM) += zram.o diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c new file mode 100644 index 0000000..d22e5ad --- /dev/null +++ b/drivers/block/zram/zram_drv.c @@ -0,0 +1,1004 @@ +/* + * Compressed RAM block device + * + * Copyright (C) 2008, 2009, 2010 Nitin Gupta + * + * 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 + * + * Project home: http://compcache.googlecode.com + */ + +#define KMSG_COMPONENT "zram" +#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt + +#ifdef CONFIG_ZRAM_DEBUG +#define DEBUG +#endif + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/bio.h> +#include <linux/bitops.h> +#include <linux/blkdev.h> +#include <linux/buffer_head.h> +#include <linux/device.h> +#include <linux/genhd.h> +#include <linux/highmem.h> +#include <linux/slab.h> +#include <linux/lzo.h> +#include <linux/string.h> +#include <linux/vmalloc.h> +#include <linux/ratelimit.h> + +#include "zram_drv.h" + +/* Globals */ +static int zram_major; +static struct zram *zram_devices; + +/* + * We don't need to see memory allocation errors more than once every 1 + * second to know that a problem is occurring. + */ +#define ALLOC_ERROR_LOG_RATE_MS 1000 + +/* Module params (documentation at end) */ +static unsigned int num_devices = 1; + +static inline struct zram *dev_to_zram(struct device *dev) +{ + return (struct zram *)dev_to_disk(dev)->private_data; +} + +static ssize_t disksize_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct zram *zram = dev_to_zram(dev); + + return sprintf(buf, "%llu\n", zram->disksize); +} + +static ssize_t initstate_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct zram *zram = dev_to_zram(dev); + + return sprintf(buf, "%u\n", zram->init_done); +} + +static ssize_t num_reads_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct zram *zram = dev_to_zram(dev); + + return sprintf(buf, "%llu\n", + (u64)atomic64_read(&zram->stats.num_reads)); +} + +static ssize_t num_writes_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct zram *zram = dev_to_zram(dev); + + return sprintf(buf, "%llu\n", + (u64)atomic64_read(&zram->stats.num_writes)); +} + +static ssize_t invalid_io_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct zram *zram = dev_to_zram(dev); + + return sprintf(buf, "%llu\n", + (u64)atomic64_read(&zram->stats.invalid_io)); +} + +static ssize_t notify_free_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct zram *zram = dev_to_zram(dev); + + return sprintf(buf, "%llu\n", + (u64)atomic64_read(&zram->stats.notify_free)); +} + +static ssize_t zero_pages_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct zram *zram = dev_to_zram(dev); + + return sprintf(buf, "%u\n", zram->stats.pages_zero); +} + +static ssize_t orig_data_size_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct zram *zram = dev_to_zram(dev); + + return sprintf(buf, "%llu\n", + (u64)(zram->stats.pages_stored) << PAGE_SHIFT); +} + +static ssize_t compr_data_size_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct zram *zram = dev_to_zram(dev); + + return sprintf(buf, "%llu\n", + (u64)atomic64_read(&zram->stats.compr_size)); +} + +static ssize_t mem_used_total_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + u64 val = 0; + struct zram *zram = dev_to_zram(dev); + struct zram_meta *meta = zram->meta; + + down_read(&zram->init_lock); + if (zram->init_done) + val = zs_get_total_size_bytes(meta->mem_pool); + up_read(&zram->init_lock); + + return sprintf(buf, "%llu\n", val); +} + +static int zram_test_flag(struct zram_meta *meta, u32 index, + enum zram_pageflags flag) +{ + return meta->table[index].flags & BIT(flag); +} + +static void zram_set_flag(struct zram_meta *meta, u32 index, + enum zram_pageflags flag) +{ + meta->table[index].flags |= BIT(flag); +} + +static void zram_clear_flag(struct zram_meta *meta, u32 index, + enum zram_pageflags flag) +{ + meta->table[index].flags &= ~BIT(flag); +} + +static inline int is_partial_io(struct bio_vec *bvec) +{ + return bvec->bv_len != PAGE_SIZE; +} + +/* + * Check if request is within bounds and aligned on zram logical blocks. + */ +static inline int valid_io_request(struct zram *zram, struct bio *bio) +{ + u64 start, end, bound; + + /* unaligned request */ + if (unlikely(bio->bi_sector & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1))) + return 0; + if (unlikely(bio->bi_size & (ZRAM_LOGICAL_BLOCK_SIZE - 1))) + return 0; + + start = bio->bi_sector; + end = start + (bio->bi_size >> SECTOR_SHIFT); + bound = zram->disksize >> SECTOR_SHIFT; + /* out of range range */ + if (unlikely(start >= bound || end > bound || start > end)) + return 0; + + /* I/O request is valid */ + return 1; +} + +static void zram_meta_free(struct zram_meta *meta) +{ + zs_destroy_pool(meta->mem_pool); + kfree(meta->compress_workmem); + free_pages((unsigned long)meta->compress_buffer, 1); + vfree(meta->table); + kfree(meta); +} + +static struct zram_meta *zram_meta_alloc(u64 disksize) +{ + size_t num_pages; + struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL); + if (!meta) + goto out; + + meta->compress_workmem = kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL); + if (!meta->compress_workmem) + goto free_meta; + + meta->compress_buffer = + (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1); + if (!meta->compress_buffer) { + pr_err("Error allocating compressor buffer space\n"); + goto free_workmem; + } + + num_pages = disksize >> PAGE_SHIFT; + meta->table = vzalloc(num_pages * sizeof(*meta->table)); + if (!meta->table) { + pr_err("Error allocating zram address table\n"); + goto free_buffer; + } + + meta->mem_pool = zs_create_pool(GFP_NOIO | __GFP_HIGHMEM | + __GFP_NOWARN); + if (!meta->mem_pool) { + pr_err("Error creating memory pool\n"); + goto free_table; + } + + return meta; + +free_table: + vfree(meta->table); +free_buffer: + free_pages((unsigned long)meta->compress_buffer, 1); +free_workmem: + kfree(meta->compress_workmem); +free_meta: + kfree(meta); + meta = NULL; +out: + return meta; +} + +static void update_position(u32 *index, int *offset, struct bio_vec *bvec) +{ + if (*offset + bvec->bv_len >= PAGE_SIZE) + (*index)++; + *offset = (*offset + bvec->bv_len) % PAGE_SIZE; +} + +static int page_zero_filled(void *ptr) +{ + unsigned int pos; + unsigned long *page; + + page = (unsigned long *)ptr; + + for (pos = 0; pos != PAGE_SIZE / sizeof(*page); pos++) { + if (page[pos]) + return 0; + } + + return 1; +} + +static void handle_zero_page(struct bio_vec *bvec) +{ + struct page *page = bvec->bv_page; + void *user_mem; + + user_mem = kmap_atomic(page); + if (is_partial_io(bvec)) + memset(user_mem + bvec->bv_offset, 0, bvec->bv_len); + else + clear_page(user_mem); + kunmap_atomic(user_mem); + + flush_dcache_page(page); +} + +static void zram_free_page(struct zram *zram, size_t index) +{ + struct zram_meta *meta = zram->meta; + unsigned long handle = meta->table[index].handle; + u16 size = meta->table[index].size; + + if (unlikely(!handle)) { + /* + * No memory is allocated for zero filled pages. + * Simply clear zero page flag. + */ + if (zram_test_flag(meta, index, ZRAM_ZERO)) { + zram_clear_flag(meta, index, ZRAM_ZERO); + zram->stats.pages_zero--; + } + return; + } + + if (unlikely(size > max_zpage_size)) + zram->stats.bad_compress--; + + zs_free(meta->mem_pool, handle); + + if (size <= PAGE_SIZE / 2) + zram->stats.good_compress--; + + atomic64_sub(meta->table[index].size, &zram->stats.compr_size); + zram->stats.pages_stored--; + + meta->table[index].handle = 0; + meta->table[index].size = 0; +} + +static int zram_decompress_page(struct zram *zram, char *mem, u32 index) +{ + int ret = LZO_E_OK; + size_t clen = PAGE_SIZE; + unsigned char *cmem; + struct zram_meta *meta = zram->meta; + unsigned long handle = meta->table[index].handle; + + if (!handle || zram_test_flag(meta, index, ZRAM_ZERO)) { + clear_page(mem); + return 0; + } + + cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO); + if (meta->table[index].size == PAGE_SIZE) + copy_page(mem, cmem); + else + ret = lzo1x_decompress_safe(cmem, meta->table[index].size, + mem, &clen); + zs_unmap_object(meta->mem_pool, handle); + + /* Should NEVER happen. Return bio error if it does. */ + if (unlikely(ret != LZO_E_OK)) { + pr_err("Decompression failed! err=%d, page=%u\n", ret, index); + atomic64_inc(&zram->stats.failed_reads); + return ret; + } + + return 0; +} + +static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, + u32 index, int offset, struct bio *bio) +{ + int ret; + struct page *page; + unsigned char *user_mem, *uncmem = NULL; + struct zram_meta *meta = zram->meta; + page = bvec->bv_page; + + if (unlikely(!meta->table[index].handle) || + zram_test_flag(meta, index, ZRAM_ZERO)) { + handle_zero_page(bvec); + return 0; + } + + if (is_partial_io(bvec)) + /* Use a temporary buffer to decompress the page */ + uncmem = kmalloc(PAGE_SIZE, GFP_NOIO); + + user_mem = kmap_atomic(page); + if (!is_partial_io(bvec)) + uncmem = user_mem; + + if (!uncmem) { + pr_info("Unable to allocate temp memory\n"); + ret = -ENOMEM; + goto out_cleanup; + } + + ret = zram_decompress_page(zram, uncmem, index); + /* Should NEVER happen. Return bio error if it does. */ + if (unlikely(ret != LZO_E_OK)) + goto out_cleanup; + + if (is_partial_io(bvec)) + memcpy(user_mem + bvec->bv_offset, uncmem + offset, + bvec->bv_len); + + flush_dcache_page(page); + ret = 0; +out_cleanup: + kunmap_atomic(user_mem); + if (is_partial_io(bvec)) + kfree(uncmem); + return ret; +} + +static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, + int offset) +{ + int ret = 0; + size_t clen; + unsigned long handle; + struct page *page; + unsigned char *user_mem, *cmem, *src, *uncmem = NULL; + struct zram_meta *meta = zram->meta; + static unsigned long zram_rs_time; + + page = bvec->bv_page; + src = meta->compress_buffer; + + if (is_partial_io(bvec)) { + /* + * This is a partial IO. We need to read the full page + * before to write the changes. + */ + uncmem = kmalloc(PAGE_SIZE, GFP_NOIO); + if (!uncmem) { + ret = -ENOMEM; + goto out; + } + ret = zram_decompress_page(zram, uncmem, index); + if (ret) + goto out; + } + + user_mem = kmap_atomic(page); + + if (is_partial_io(bvec)) { + memcpy(uncmem + offset, user_mem + bvec->bv_offset, + bvec->bv_len); + kunmap_atomic(user_mem); + user_mem = NULL; + } else { + uncmem = user_mem; + } + + if (page_zero_filled(uncmem)) { + kunmap_atomic(user_mem); + /* Free memory associated with this sector now. */ + zram_free_page(zram, index); + + zram->stats.pages_zero++; + zram_set_flag(meta, index, ZRAM_ZERO); + ret = 0; + goto out; + } + + /* + * zram_slot_free_notify could miss free so that let's + * double check. + */ + if (unlikely(meta->table[index].handle || + zram_test_flag(meta, index, ZRAM_ZERO))) + zram_free_page(zram, index); + + ret = lzo1x_1_compress(uncmem, PAGE_SIZE, src, &clen, + meta->compress_workmem); + + if (!is_partial_io(bvec)) { + kunmap_atomic(user_mem); + user_mem = NULL; + uncmem = NULL; + } + + if (unlikely(ret != LZO_E_OK)) { + pr_err("Compression failed! err=%d\n", ret); + goto out; + } + + if (unlikely(clen > max_zpage_size)) { + zram->stats.bad_compress++; + clen = PAGE_SIZE; + src = NULL; + if (is_partial_io(bvec)) + src = uncmem; + } + + handle = zs_malloc(meta->mem_pool, clen); + if (!handle) { + if (printk_timed_ratelimit(&zram_rs_time, + ALLOC_ERROR_LOG_RATE_MS)) + pr_info("Error allocating memory for compressed page: %u, size=%zu\n", + index, clen); + ret = -ENOMEM; + goto out; + } + cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO); + + if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) { + src = kmap_atomic(page); + copy_page(cmem, src); + kunmap_atomic(src); + } else { + memcpy(cmem, src, clen); + } + + zs_unmap_object(meta->mem_pool, handle); + + /* + * Free memory associated with this sector + * before overwriting unused sectors. + */ + zram_free_page(zram, index); + + meta->table[index].handle = handle; + meta->table[index].size = clen; + + /* Update stats */ + atomic64_add(clen, &zram->stats.compr_size); + zram->stats.pages_stored++; + if (clen <= PAGE_SIZE / 2) + zram->stats.good_compress++; + +out: + if (is_partial_io(bvec)) + kfree(uncmem); + + if (ret) + atomic64_inc(&zram->stats.failed_writes); + return ret; +} + +static void handle_pending_slot_free(struct zram *zram) +{ + struct zram_slot_free *free_rq; + + spin_lock(&zram->slot_free_lock); + while (zram->slot_free_rq) { + free_rq = zram->slot_free_rq; + zram->slot_free_rq = free_rq->next; + zram_free_page(zram, free_rq->index); + kfree(free_rq); + } + spin_unlock(&zram->slot_free_lock); +} + +static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, + int offset, struct bio *bio, int rw) +{ + int ret; + + if (rw == READ) { + down_read(&zram->lock); + handle_pending_slot_free(zram); + ret = zram_bvec_read(zram, bvec, index, offset, bio); + up_read(&zram->lock); + } else { + down_write(&zram->lock); + handle_pending_slot_free(zram); + ret = zram_bvec_write(zram, bvec, index, offset); + up_write(&zram->lock); + } + + return ret; +} + +static void zram_reset_device(struct zram *zram, bool reset_capacity) +{ + size_t index; + struct zram_meta *meta; + + flush_work(&zram->free_work); + + down_write(&zram->init_lock); + if (!zram->init_done) { + up_write(&zram->init_lock); + return; + } + + meta = zram->meta; + zram->init_done = 0; + + /* Free all pages that are still in this zram device */ + for (index = 0; index < zram->disksize >> PAGE_SHIFT; index++) { + unsigned long handle = meta->table[index].handle; + if (!handle) + continue; + + zs_free(meta->mem_pool, handle); + } + + zram_meta_free(zram->meta); + zram->meta = NULL; + /* Reset stats */ + memset(&zram->stats, 0, sizeof(zram->stats)); + + zram->disksize = 0; + if (reset_capacity) + set_capacity(zram->disk, 0); + up_write(&zram->init_lock); +} + +static void zram_init_device(struct zram *zram, struct zram_meta *meta) +{ + if (zram->disksize > 2 * (totalram_pages << PAGE_SHIFT)) { + pr_info( + "There is little point creating a zram of greater than " + "twice the size of memory since we expect a 2:1 compression " + "ratio. Note that zram uses about 0.1%% of the size of " + "the disk when not in use so a huge zram is " + "wasteful.\n" + "\tMemory Size: %lu kB\n" + "\tSize you selected: %llu kB\n" + "Continuing anyway ...\n", + (totalram_pages << PAGE_SHIFT) >> 10, zram->disksize >> 10 + ); + } + + /* zram devices sort of resembles non-rotational disks */ + queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue); + + zram->meta = meta; + zram->init_done = 1; + + pr_debug("Initialization done!\n"); +} + +static ssize_t disksize_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t len) +{ + u64 disksize; + struct zram_meta *meta; + struct zram *zram = dev_to_zram(dev); + + disksize = memparse(buf, NULL); + if (!disksize) + return -EINVAL; + + disksize = PAGE_ALIGN(disksize); + meta = zram_meta_alloc(disksize); + down_write(&zram->init_lock); + if (zram->init_done) { + up_write(&zram->init_lock); + zram_meta_free(meta); + pr_info("Cannot change disksize for initialized device\n"); + return -EBUSY; + } + + zram->disksize = disksize; + set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT); + zram_init_device(zram, meta); + up_write(&zram->init_lock); + + return len; +} + +static ssize_t reset_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t len) +{ + int ret; + unsigned short do_reset; + struct zram *zram; + struct block_device *bdev; + + zram = dev_to_zram(dev); + bdev = bdget_disk(zram->disk, 0); + + if (!bdev) + return -ENOMEM; + + /* Do not reset an active device! */ + if (bdev->bd_holders) { + ret = -EBUSY; + goto out; + } + + ret = kstrtou16(buf, 10, &do_reset); + if (ret) + goto out; + + if (!do_reset) { + ret = -EINVAL; + goto out; + } + + /* Make sure all pending I/O is finished */ + fsync_bdev(bdev); + bdput(bdev); + + zram_reset_device(zram, true); + return len; + +out: + bdput(bdev); + return ret; +} + +static void __zram_make_request(struct zram *zram, struct bio *bio, int rw) +{ + int i, offset; + u32 index; + struct bio_vec *bvec; + + switch (rw) { + case READ: + atomic64_inc(&zram->stats.num_reads); + break; + case WRITE: + atomic64_inc(&zram->stats.num_writes); + break; + } + + index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT; + offset = (bio->bi_sector & (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT; + + bio_for_each_segment(bvec, bio, i) { + int max_transfer_size = PAGE_SIZE - offset; + + if (bvec->bv_len > max_transfer_size) { + /* + * zram_bvec_rw() can only make operation on a single + * zram page. Split the bio vector. + */ + struct bio_vec bv; + + bv.bv_page = bvec->bv_page; + bv.bv_len = max_transfer_size; + bv.bv_offset = bvec->bv_offset; + + if (zram_bvec_rw(zram, &bv, index, offset, bio, rw) < 0) + goto out; + + bv.bv_len = bvec->bv_len - max_transfer_size; + bv.bv_offset += max_transfer_size; + if (zram_bvec_rw(zram, &bv, index+1, 0, bio, rw) < 0) + goto out; + } else + if (zram_bvec_rw(zram, bvec, index, offset, bio, rw) + < 0) + goto out; + + update_position(&index, &offset, bvec); + } + + set_bit(BIO_UPTODATE, &bio->bi_flags); + bio_endio(bio, 0); + return; + +out: + bio_io_error(bio); +} + +/* + * Handler function for all zram I/O requests. + */ +static int zram_make_request(struct request_queue *queue, struct bio *bio) +{ + struct zram *zram = queue->queuedata; + + down_read(&zram->init_lock); + if (unlikely(!zram->init_done)) + goto error; + + if (!valid_io_request(zram, bio)) { + atomic64_inc(&zram->stats.invalid_io); + goto error; + } + + __zram_make_request(zram, bio, bio_data_dir(bio)); + up_read(&zram->init_lock); + + return 0; + +error: + up_read(&zram->init_lock); + bio_io_error(bio); + + return 0; +} + +static void zram_slot_free(struct work_struct *work) +{ + struct zram *zram; + + zram = container_of(work, struct zram, free_work); + down_write(&zram->lock); + handle_pending_slot_free(zram); + up_write(&zram->lock); +} + +static void add_slot_free(struct zram *zram, struct zram_slot_free *free_rq) +{ + spin_lock(&zram->slot_free_lock); + free_rq->next = zram->slot_free_rq; + zram->slot_free_rq = free_rq; + spin_unlock(&zram->slot_free_lock); +} + +static void zram_slot_free_notify(struct block_device *bdev, + unsigned long index) +{ + struct zram *zram; + struct zram_slot_free *free_rq; + + zram = bdev->bd_disk->private_data; + atomic64_inc(&zram->stats.notify_free); + + free_rq = kmalloc(sizeof(struct zram_slot_free), GFP_ATOMIC); + if (!free_rq) + return; + + free_rq->index = index; + add_slot_free(zram, free_rq); + schedule_work(&zram->free_work); +} + +static const struct block_device_operations zram_devops = { + .swap_slot_free_notify = zram_slot_free_notify, + .owner = THIS_MODULE +}; + +static DEVICE_ATTR(disksize, S_IRUGO | S_IWUSR, + disksize_show, disksize_store); +static DEVICE_ATTR(initstate, S_IRUGO, initstate_show, NULL); +static DEVICE_ATTR(reset, S_IWUSR, NULL, reset_store); +static DEVICE_ATTR(num_reads, S_IRUGO, num_reads_show, NULL); +static DEVICE_ATTR(num_writes, S_IRUGO, num_writes_show, NULL); +static DEVICE_ATTR(invalid_io, S_IRUGO, invalid_io_show, NULL); +static DEVICE_ATTR(notify_free, S_IRUGO, notify_free_show, NULL); +static DEVICE_ATTR(zero_pages, S_IRUGO, zero_pages_show, NULL); +static DEVICE_ATTR(orig_data_size, S_IRUGO, orig_data_size_show, NULL); +static DEVICE_ATTR(compr_data_size, S_IRUGO, compr_data_size_show, NULL); +static DEVICE_ATTR(mem_used_total, S_IRUGO, mem_used_total_show, NULL); + +static struct attribute *zram_disk_attrs[] = { + &dev_attr_disksize.attr, + &dev_attr_initstate.attr, + &dev_attr_reset.attr, + &dev_attr_num_reads.attr, + &dev_attr_num_writes.attr, + &dev_attr_invalid_io.attr, + &dev_attr_notify_free.attr, + &dev_attr_zero_pages.attr, + &dev_attr_orig_data_size.attr, + &dev_attr_compr_data_size.attr, + &dev_attr_mem_used_total.attr, + NULL, +}; + +static struct attribute_group zram_disk_attr_group = { + .attrs = zram_disk_attrs, +}; + +static int create_device(struct zram *zram, int device_id) +{ + int ret = -ENOMEM; + + init_rwsem(&zram->lock); + init_rwsem(&zram->init_lock); + + INIT_WORK(&zram->free_work, zram_slot_free); + spin_lock_init(&zram->slot_free_lock); + zram->slot_free_rq = NULL; + + zram->queue = blk_alloc_queue(GFP_KERNEL); + if (!zram->queue) { + pr_err("Error allocating disk queue for device %d\n", + device_id); + goto out; + } + + blk_queue_make_request(zram->queue, zram_make_request); + zram->queue->queuedata = zram; + + /* gendisk structure */ + zram->disk = alloc_disk(1); + if (!zram->disk) { + pr_warn("Error allocating disk structure for device %d\n", + device_id); + goto out_free_queue; + } + + zram->disk->major = zram_major; + zram->disk->first_minor = device_id; + zram->disk->fops = &zram_devops; + zram->disk->queue = zram->queue; + zram->disk->private_data = zram; + snprintf(zram->disk->disk_name, 16, "zram%d", device_id); + + /* Actual capacity set using syfs (/sys/block/zram<id>/disksize */ + set_capacity(zram->disk, 0); + + /* + * To ensure that we always get PAGE_SIZE aligned + * and n*PAGE_SIZED sized I/O requests. + */ + blk_queue_physical_block_size(zram->disk->queue, PAGE_SIZE); + blk_queue_logical_block_size(zram->disk->queue, + ZRAM_LOGICAL_BLOCK_SIZE); + blk_queue_io_min(zram->disk->queue, PAGE_SIZE); + blk_queue_io_opt(zram->disk->queue, PAGE_SIZE); + + add_disk(zram->disk); + + ret = sysfs_create_group(&disk_to_dev(zram->disk)->kobj, + &zram_disk_attr_group); + if (ret < 0) { + pr_warn("Error creating sysfs group"); + goto out_free_disk; + } + + zram->init_done = 0; + return 0; + +out_free_disk: + del_gendisk(zram->disk); + put_disk(zram->disk); +out_free_queue: + blk_cleanup_queue(zram->queue); +out: + return ret; +} + +static void destroy_device(struct zram *zram) +{ + sysfs_remove_group(&disk_to_dev(zram->disk)->kobj, + &zram_disk_attr_group); + + del_gendisk(zram->disk); + put_disk(zram->disk); + + blk_cleanup_queue(zram->queue); +} + +static int __init zram_init(void) +{ + int ret, dev_id; + + if (num_devices > max_num_devices) { + pr_warn("Invalid value for num_devices: %u\n", + num_devices); + ret = -EINVAL; + goto out; + } + + zram_major = register_blkdev(0, "zram"); + if (zram_major <= 0) { + pr_warn("Unable to get major number\n"); + ret = -EBUSY; + goto out; + } + + /* Allocate the device array and initialize each one */ + zram_devices = kzalloc(num_devices * sizeof(struct zram), GFP_KERNEL); + if (!zram_devices) { + ret = -ENOMEM; + goto unregister; + } + + for (dev_id = 0; dev_id < num_devices; dev_id++) { + ret = create_device(&zram_devices[dev_id], dev_id); + if (ret) + goto free_devices; + } + + pr_info("Created %u device(s) ...\n", num_devices); + + return 0; + +free_devices: + while (dev_id) + destroy_device(&zram_devices[--dev_id]); + kfree(zram_devices); +unregister: + unregister_blkdev(zram_major, "zram"); +out: + return ret; +} + +static void __exit zram_exit(void) +{ + int i; + struct zram *zram; + + for (i = 0; i < num_devices; i++) { + zram = &zram_devices[i]; + + destroy_device(zram); + /* + * Shouldn't access zram->disk after destroy_device + * because destroy_device already released zram->disk. + */ + zram_reset_device(zram, false); + } + + unregister_blkdev(zram_major, "zram"); + + kfree(zram_devices); + pr_debug("Cleanup done!\n"); +} + +module_init(zram_init); +module_exit(zram_exit); + +module_param(num_devices, uint, 0); +MODULE_PARM_DESC(num_devices, "Number of zram devices"); + +MODULE_LICENSE("Dual BSD/GPL"); +MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>"); +MODULE_DESCRIPTION("Compressed RAM Block Device"); diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h new file mode 100644 index 0000000..1c39fed --- /dev/null +++ b/drivers/block/zram/zram_drv.h @@ -0,0 +1,124 @@ +/* + * Compressed RAM block device + * + * Copyright (C) 2008, 2009, 2010 Nitin Gupta + * + * 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 + * + * Project home: http://compcache.googlecode.com + */ + +#ifndef _ZRAM_DRV_H_ +#define _ZRAM_DRV_H_ + +#include <linux/spinlock.h> +#include <linux/mutex.h> +#include <linux/zsmalloc.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 / 10 * 9; + +/* + * 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 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 +#define ZRAM_LOGICAL_BLOCK_SIZE (1 << ZRAM_LOGICAL_BLOCK_SHIFT) +#define ZRAM_SECTOR_PER_LOGICAL_BLOCK \ + (1 << (ZRAM_LOGICAL_BLOCK_SHIFT - SECTOR_SHIFT)) + +/* Flags for zram pages (table[page_no].flags) */ +enum zram_pageflags { + /* Page consists entirely of zeros */ + ZRAM_ZERO, + + __NR_ZRAM_PAGEFLAGS, +}; + +/*-- Data structures */ + +/* Allocated for each disk page */ +struct table { + unsigned long handle; + u16 size; /* object size (excluding header) */ + u8 count; /* object ref count (not yet used) */ + u8 flags; +} __aligned(4); + +/* + * All 64bit fields should only be manipulated by 64bit atomic accessors. + * All modifications to 32bit counter should be protected by zram->lock. + */ +struct zram_stats { + atomic64_t compr_size; /* compressed size of pages stored */ + atomic64_t num_reads; /* failed + successful */ + atomic64_t num_writes; /* --do-- */ + atomic64_t failed_reads; /* should NEVER! happen */ + 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 */ + u32 pages_zero; /* no. of zero filled pages */ + u32 pages_stored; /* no. of pages currently stored */ + u32 good_compress; /* % of pages with compression ratio<=50% */ + u32 bad_compress; /* % of pages with compression ratio>=75% */ +}; + +struct zram_meta { + void *compress_workmem; + void *compress_buffer; + struct table *table; + struct zs_pool *mem_pool; +}; + +struct zram_slot_free { + unsigned long index; + struct zram_slot_free *next; +}; + +struct zram { + struct zram_meta *meta; + struct rw_semaphore lock; /* protect compression buffers, table, + * 32bit stat counters against concurrent + * notifications, reads and writes */ + + struct work_struct free_work; /* handle pending free request */ + struct zram_slot_free *slot_free_rq; /* list head of free request */ + + struct request_queue *queue; + struct gendisk *disk; + int init_done; + /* Prevent concurrent execution of device init, reset and R/W request */ + struct rw_semaphore init_lock; + /* + * This is the limit on amount of *uncompressed* worth of data + * we can store in a disk. + */ + u64 disksize; /* bytes */ + spinlock_t slot_free_lock; + + struct zram_stats stats; +}; +#endif |