diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-block-zram | 9 | ||||
| -rw-r--r-- | Documentation/blockdev/zram.txt | 31 | ||||
| -rw-r--r-- | drivers/block/zram/zcomp.c | 124 | ||||
| -rw-r--r-- | drivers/block/zram/zcomp.h | 4 | ||||
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 42 | ||||
| -rw-r--r-- | drivers/block/zram/zram_drv.h | 2 |
6 files changed, 201 insertions, 11 deletions
diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram index d460d12..9fe4c51 100644 --- a/Documentation/ABI/testing/sysfs-block-zram +++ b/Documentation/ABI/testing/sysfs-block-zram @@ -49,7 +49,6 @@ Description: The failed_reads file is read-only and specifies the number of failed reads happened on this device. - What: /sys/block/zram<id>/failed_writes Date: February 2014 Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> @@ -57,6 +56,14 @@ Description: The failed_writes file is read-only and specifies the number of failed writes happened on this device. +What: /sys/block/zram<id>/max_comp_streams +Date: February 2014 +Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> +Description: + The max_comp_streams file is read-write and specifies the + number of backend's zcomp_strm compression streams (number of + concurrent compress operations). + What: /sys/block/zram<id>/notify_free Date: August 2010 Contact: Nitin Gupta <ngupta@vflare.org> diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt index d389fb7..ad29acf 100644 --- a/Documentation/blockdev/zram.txt +++ b/Documentation/blockdev/zram.txt @@ -23,7 +23,28 @@ Following shows a typical sequence of steps for using zram. This creates 4 devices: /dev/zram{0,1,2,3} (num_devices parameter is optional. Default: 1) -2) Set Disksize +2) Set max number of compression streams + Compression backend may use up to max_comp_streams compression streams, + thus allowing up to max_comp_streams concurrent compression operations. + By default, compression backend uses single compression stream. + + Examples: + #show max compression streams number + cat /sys/block/zram0/max_comp_streams + + #set max compression streams number to 3 + echo 3 > /sys/block/zram0/max_comp_streams + +Note: +In order to enable compression backend's multi stream support max_comp_streams +must be initially set to desired concurrency level before ZRAM device +initialisation. Once the device initialised as a single stream compression +backend (max_comp_streams equals to 0) changing the value of max_comp_streams +will not take any effect, because single stream compression backend implemented +as a special case and does not support dynamic max_comp_streams. Only multi +stream backend supports dynamic max_comp_streams adjustment. + +3) Set Disksize Set disk size by writing the value to sysfs node 'disksize'. The value can be either in bytes or you can use mem suffixes. Examples: @@ -40,14 +61,14 @@ 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. -3) Activate: +4) Activate: mkswap /dev/zram0 swapon /dev/zram0 mkfs.ext4 /dev/zram1 mount /dev/zram1 /tmp -4) Stats: +5) Stats: Per-device statistics are exported as various nodes under /sys/block/zram<id>/ disksize @@ -62,11 +83,11 @@ size of the disk when not in use so a huge zram is wasteful. compr_data_size mem_used_total -5) Deactivate: +6) Deactivate: swapoff /dev/zram0 umount /dev/zram1 -6) Reset: +7) Reset: Write any positive value to 'reset' sysfs node echo 1 > /sys/block/zram0/reset echo 1 > /sys/block/zram1/reset diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c index 72e8071..c06f75f 100644 --- a/drivers/block/zram/zcomp.c +++ b/drivers/block/zram/zcomp.c @@ -24,6 +24,21 @@ struct zcomp_strm_single { struct zcomp_strm *zstrm; }; +/* + * multi zcomp_strm backend + */ +struct zcomp_strm_multi { + /* protect strm list */ + spinlock_t strm_lock; + /* max possible number of zstrm streams */ + int max_strm; + /* number of available zstrm streams */ + int avail_strm; + /* list of available strms */ + struct list_head idle_strm; + wait_queue_head_t strm_wait; +}; + static struct zcomp_backend *find_backend(const char *compress) { if (strncmp(compress, "lzo", 3) == 0) @@ -62,6 +77,107 @@ static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp) return zstrm; } +/* + * get idle zcomp_strm or wait until other process release + * (zcomp_strm_release()) one for us + */ +static struct zcomp_strm *zcomp_strm_multi_find(struct zcomp *comp) +{ + struct zcomp_strm_multi *zs = comp->stream; + struct zcomp_strm *zstrm; + + while (1) { + spin_lock(&zs->strm_lock); + if (!list_empty(&zs->idle_strm)) { + zstrm = list_entry(zs->idle_strm.next, + struct zcomp_strm, list); + list_del(&zstrm->list); + spin_unlock(&zs->strm_lock); + return zstrm; + } + /* zstrm streams limit reached, wait for idle stream */ + if (zs->avail_strm >= zs->max_strm) { + spin_unlock(&zs->strm_lock); + wait_event(zs->strm_wait, !list_empty(&zs->idle_strm)); + continue; + } + /* allocate new zstrm stream */ + zs->avail_strm++; + spin_unlock(&zs->strm_lock); + + zstrm = zcomp_strm_alloc(comp); + if (!zstrm) { + spin_lock(&zs->strm_lock); + zs->avail_strm--; + spin_unlock(&zs->strm_lock); + wait_event(zs->strm_wait, !list_empty(&zs->idle_strm)); + continue; + } + break; + } + return zstrm; +} + +/* add stream back to idle list and wake up waiter or free the stream */ +static void zcomp_strm_multi_release(struct zcomp *comp, struct zcomp_strm *zstrm) +{ + struct zcomp_strm_multi *zs = comp->stream; + + spin_lock(&zs->strm_lock); + if (zs->avail_strm <= zs->max_strm) { + list_add(&zstrm->list, &zs->idle_strm); + spin_unlock(&zs->strm_lock); + wake_up(&zs->strm_wait); + return; + } + + zs->avail_strm--; + spin_unlock(&zs->strm_lock); + zcomp_strm_free(comp, zstrm); +} + +static void zcomp_strm_multi_destroy(struct zcomp *comp) +{ + struct zcomp_strm_multi *zs = comp->stream; + struct zcomp_strm *zstrm; + + while (!list_empty(&zs->idle_strm)) { + zstrm = list_entry(zs->idle_strm.next, + struct zcomp_strm, list); + list_del(&zstrm->list); + zcomp_strm_free(comp, zstrm); + } + kfree(zs); +} + +static int zcomp_strm_multi_create(struct zcomp *comp, int max_strm) +{ + struct zcomp_strm *zstrm; + struct zcomp_strm_multi *zs; + + comp->destroy = zcomp_strm_multi_destroy; + comp->strm_find = zcomp_strm_multi_find; + comp->strm_release = zcomp_strm_multi_release; + zs = kmalloc(sizeof(struct zcomp_strm_multi), GFP_KERNEL); + if (!zs) + return -ENOMEM; + + comp->stream = zs; + spin_lock_init(&zs->strm_lock); + INIT_LIST_HEAD(&zs->idle_strm); + init_waitqueue_head(&zs->strm_wait); + zs->max_strm = max_strm; + zs->avail_strm = 1; + + zstrm = zcomp_strm_alloc(comp); + if (!zstrm) { + kfree(zs); + return -ENOMEM; + } + list_add(&zstrm->list, &zs->idle_strm); + return 0; +} + static struct zcomp_strm *zcomp_strm_single_find(struct zcomp *comp) { struct zcomp_strm_single *zs = comp->stream; @@ -139,7 +255,7 @@ void zcomp_destroy(struct zcomp *comp) * if requested algorithm is not supported or in case * of init error */ -struct zcomp *zcomp_create(const char *compress) +struct zcomp *zcomp_create(const char *compress, int max_strm) { struct zcomp *comp; struct zcomp_backend *backend; @@ -153,7 +269,11 @@ struct zcomp *zcomp_create(const char *compress) return NULL; comp->backend = backend; - if (zcomp_strm_single_create(comp) != 0) { + if (max_strm > 1) + zcomp_strm_multi_create(comp, max_strm); + else + zcomp_strm_single_create(comp); + if (!comp->stream) { kfree(comp); return NULL; } diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h index dc3500d..2a36844 100644 --- a/drivers/block/zram/zcomp.h +++ b/drivers/block/zram/zcomp.h @@ -21,6 +21,8 @@ struct zcomp_strm { * working memory) */ void *private; + /* used in multi stream backend, protected by backend strm_lock */ + struct list_head list; }; /* static compression backend */ @@ -47,7 +49,7 @@ struct zcomp { void (*destroy)(struct zcomp *comp); }; -struct zcomp *zcomp_create(const char *comp); +struct zcomp *zcomp_create(const char *comp, int max_strm); void zcomp_destroy(struct zcomp *comp); struct zcomp_strm *zcomp_strm_find(struct zcomp *comp); diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 9678407..d498c82 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -116,6 +116,40 @@ static ssize_t mem_used_total_show(struct device *dev, return sprintf(buf, "%llu\n", val); } +static ssize_t max_comp_streams_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int val; + struct zram *zram = dev_to_zram(dev); + + down_read(&zram->init_lock); + val = zram->max_comp_streams; + up_read(&zram->init_lock); + + return sprintf(buf, "%d\n", val); +} + +static ssize_t max_comp_streams_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t len) +{ + int num; + struct zram *zram = dev_to_zram(dev); + + if (kstrtoint(buf, 0, &num)) + return -EINVAL; + if (num < 1) + return -EINVAL; + down_write(&zram->init_lock); + if (init_done(zram)) { + up_write(&zram->init_lock); + pr_info("Can't set max_comp_streams for initialized device\n"); + return -EBUSY; + } + zram->max_comp_streams = num; + up_write(&zram->init_lock); + return len; +} + /* flag operations needs meta->tb_lock */ static int zram_test_flag(struct zram_meta *meta, u32 index, enum zram_pageflags flag) @@ -513,6 +547,8 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity) } zcomp_destroy(zram->comp); + zram->max_comp_streams = 1; + zram_meta_free(zram->meta); zram->meta = NULL; /* Reset stats */ @@ -548,7 +584,7 @@ static ssize_t disksize_store(struct device *dev, goto out_free_meta; } - zram->comp = zcomp_create(default_compressor); + zram->comp = zcomp_create(default_compressor, zram->max_comp_streams); if (!zram->comp) { pr_info("Cannot initialise %s compressing backend\n", default_compressor); @@ -709,6 +745,8 @@ static DEVICE_ATTR(initstate, S_IRUGO, initstate_show, NULL); static DEVICE_ATTR(reset, S_IWUSR, NULL, reset_store); static DEVICE_ATTR(orig_data_size, S_IRUGO, orig_data_size_show, NULL); static DEVICE_ATTR(mem_used_total, S_IRUGO, mem_used_total_show, NULL); +static DEVICE_ATTR(max_comp_streams, S_IRUGO | S_IWUSR, + max_comp_streams_show, max_comp_streams_store); ZRAM_ATTR_RO(num_reads); ZRAM_ATTR_RO(num_writes); @@ -733,6 +771,7 @@ static struct attribute *zram_disk_attrs[] = { &dev_attr_orig_data_size.attr, &dev_attr_compr_data_size.attr, &dev_attr_mem_used_total.attr, + &dev_attr_max_comp_streams.attr, NULL, }; @@ -795,6 +834,7 @@ static int create_device(struct zram *zram, int device_id) } zram->meta = NULL; + zram->max_comp_streams = 1; return 0; out_free_disk: diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h index c6b910e..9e1d3fd 100644 --- a/drivers/block/zram/zram_drv.h +++ b/drivers/block/zram/zram_drv.h @@ -100,7 +100,7 @@ struct zram { * we can store in a disk. */ u64 disksize; /* bytes */ - + int max_comp_streams; struct zram_stats stats; }; #endif |