zram: support compaction

Now that zsmalloc supports compaction, zram can use it.  For the first
step, this patch exports compact knob via sysfs so user can do compaction
via "echo 1 > /sys/block/zram0/compact".

Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Juneho Choi <juno.choi@lge.com>
Cc: Gunho Lee <gunho.lee@lge.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram
index a6148eaf91e5f32f43b8448a7ec0ee16677c83eb..bede9028a5a0d3e7ebbc1f2dfeab08d58828b4cd 100644 (file)
--- a/Documentation/ABI/testing/sysfs-block-zram
+++ b/Documentation/ABI/testing/sysfs-block-zram
@@ -141,3 +141,18 @@ Description:
                amount of memory ZRAM can use to store the compressed data.  The
                limit could be changed in run time and "0" means disable the
                limit.  No limit is the initial state.  Unit: bytes
+
+What:          /sys/block/zram<id>/compact
+Date:          August 2015
+Contact:       Minchan Kim <minchan@kernel.org>
+Description:
+               The compact file is write-only and trigger compaction for
+               allocator zrm uses. The allocator moves some objects so that
+               it could free fragment space.
+
+What:          /sys/block/zram<id>/num_migrated
+Date:          August 2015
+Contact:       Minchan Kim <minchan@kernel.org>
+Description:
+               The compact file is read-only and shows how many object
+               migrated by compaction.

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 871bd3550cb0e0842296771412e749225542ffac..1626961fdb2f1306b1c47d7e7cd88a3df3ab3b57 100644 (file)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -63,6 +63,27 @@ static inline struct zram *dev_to_zram(struct device *dev)
        return (struct zram *)dev_to_disk(dev)->private_data;
 }
 
+static ssize_t compact_store(struct device *dev,
+               struct device_attribute *attr, const char *buf, size_t len)
+{
+       unsigned long nr_migrated;
+       struct zram *zram = dev_to_zram(dev);
+       struct zram_meta *meta;
+
+       down_read(&zram->init_lock);
+       if (!init_done(zram)) {
+               up_read(&zram->init_lock);
+               return -EINVAL;
+       }
+
+       meta = zram->meta;
+       nr_migrated = zs_compact(meta->mem_pool);
+       atomic64_add(nr_migrated, &zram->stats.num_migrated);
+       up_read(&zram->init_lock);
+
+       return len;
+}
+
 static ssize_t disksize_show(struct device *dev,
                struct device_attribute *attr, char *buf)
 {
@@ -1017,6 +1038,7 @@ static const struct block_device_operations zram_devops = {
        .owner = THIS_MODULE
 };
 
+static DEVICE_ATTR_WO(compact);
 static DEVICE_ATTR_RW(disksize);
 static DEVICE_ATTR_RO(initstate);
 static DEVICE_ATTR_WO(reset);
@@ -1035,6 +1057,7 @@ ZRAM_ATTR_RO(invalid_io);
 ZRAM_ATTR_RO(notify_free);
 ZRAM_ATTR_RO(zero_pages);
 ZRAM_ATTR_RO(compr_data_size);
+ZRAM_ATTR_RO(num_migrated);
 
 static struct attribute *zram_disk_attrs[] = {
        &dev_attr_disksize.attr,
@@ -1044,6 +1067,8 @@ static struct attribute *zram_disk_attrs[] = {
        &dev_attr_num_writes.attr,
        &dev_attr_failed_reads.attr,
        &dev_attr_failed_writes.attr,
+       &dev_attr_num_migrated.attr,
+       &dev_attr_compact.attr,
        &dev_attr_invalid_io.attr,
        &dev_attr_notify_free.attr,
        &dev_attr_zero_pages.attr,

diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 17056e5891467caafc3a238633f9b3eb6b094158..570c598f4ce9af9fca13f99f8c214cf0f24f874f 100644 (file)
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -84,6 +84,7 @@ 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 */