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authorSergey Senozhatsky <sergey.senozhatsky@gmail.com>2014-04-07 15:38:17 -0700
committerAlex Shi <alex.shi@linaro.org>2015-05-11 20:43:29 +0800
commit0626b80d185372c3b9f28f5c6c5e11647f381472 (patch)
tree086eef015de427817d325ab87e793bfa71318a6e /drivers
parent9634c9a147869de6d78f53a49823980aaea7233c (diff)
downloadlinux-linaro-stable-0626b80d185372c3b9f28f5c6c5e11647f381472.tar.gz
zram: make compression algorithm selection possible
Add and document `comp_algorithm' device attribute. This attribute allows to show supported compression and currently selected compression algorithms: cat /sys/block/zram0/comp_algorithm [lzo] lz4 and change selected compression algorithm: echo lzo > /sys/block/zram0/comp_algorithm Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> (cherry picked from commit e46b8a030d76d3c94156c545c3f4c3676d813435) Signed-off-by: Alex Shi <alex.shi@linaro.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/block/zram/zcomp.c32
-rw-r--r--drivers/block/zram/zcomp.h2
-rw-r--r--drivers/block/zram/zram_drv.c37
-rw-r--r--drivers/block/zram/zram_drv.h1
4 files changed, 66 insertions, 6 deletions
diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index ac276f79f21c..aad533a8bc55 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -39,11 +39,20 @@ struct zcomp_strm_multi {
wait_queue_head_t strm_wait;
};
+static struct zcomp_backend *backends[] = {
+ &zcomp_lzo,
+ NULL
+};
+
static struct zcomp_backend *find_backend(const char *compress)
{
- if (strncmp(compress, "lzo", 3) == 0)
- return &zcomp_lzo;
- return NULL;
+ int i = 0;
+ while (backends[i]) {
+ if (sysfs_streq(compress, backends[i]->name))
+ break;
+ i++;
+ }
+ return backends[i];
}
static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm)
@@ -251,6 +260,23 @@ static int zcomp_strm_single_create(struct zcomp *comp)
return 0;
}
+/* show available compressors */
+ssize_t zcomp_available_show(const char *comp, char *buf)
+{
+ ssize_t sz = 0;
+ int i = 0;
+
+ while (backends[i]) {
+ if (sysfs_streq(comp, backends[i]->name))
+ sz += sprintf(buf + sz, "[%s] ", backends[i]->name);
+ else
+ sz += sprintf(buf + sz, "%s ", backends[i]->name);
+ i++;
+ }
+ sz += sprintf(buf + sz, "\n");
+ return sz;
+}
+
int zcomp_set_max_streams(struct zcomp *comp, int num_strm)
{
return comp->set_max_streams(comp, num_strm);
diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h
index bd11d59c5dd1..8b8997f8613b 100644
--- a/drivers/block/zram/zcomp.h
+++ b/drivers/block/zram/zcomp.h
@@ -50,6 +50,8 @@ struct zcomp {
void (*destroy)(struct zcomp *comp);
};
+ssize_t zcomp_available_show(const char *comp, char *buf);
+
struct zcomp *zcomp_create(const char *comp, int max_strm);
void zcomp_destroy(struct zcomp *comp);
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index c03d0053309b..f15564e65d87 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -141,6 +141,34 @@ static ssize_t max_comp_streams_store(struct device *dev,
return len;
}
+static ssize_t comp_algorithm_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ size_t sz;
+ struct zram *zram = dev_to_zram(dev);
+
+ down_read(&zram->init_lock);
+ sz = zcomp_available_show(zram->compressor, buf);
+ up_read(&zram->init_lock);
+
+ return sz;
+}
+
+static ssize_t comp_algorithm_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ struct zram *zram = dev_to_zram(dev);
+ down_write(&zram->init_lock);
+ if (init_done(zram)) {
+ up_write(&zram->init_lock);
+ pr_info("Can't change algorithm for initialized device\n");
+ return -EBUSY;
+ }
+ strlcpy(zram->compressor, buf, sizeof(zram->compressor));
+ 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)
@@ -571,10 +599,10 @@ static ssize_t disksize_store(struct device *dev,
goto out_free_meta;
}
- zram->comp = zcomp_create(default_compressor, zram->max_comp_streams);
+ zram->comp = zcomp_create(zram->compressor, zram->max_comp_streams);
if (!zram->comp) {
pr_info("Cannot initialise %s compressing backend\n",
- default_compressor);
+ zram->compressor);
err = -EINVAL;
goto out_free_meta;
}
@@ -733,6 +761,8 @@ 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);
+static DEVICE_ATTR(comp_algorithm, S_IRUGO | S_IWUSR,
+ comp_algorithm_show, comp_algorithm_store);
ZRAM_ATTR_RO(num_reads);
ZRAM_ATTR_RO(num_writes);
@@ -758,6 +788,7 @@ static struct attribute *zram_disk_attrs[] = {
&dev_attr_compr_data_size.attr,
&dev_attr_mem_used_total.attr,
&dev_attr_max_comp_streams.attr,
+ &dev_attr_comp_algorithm.attr,
NULL,
};
@@ -818,7 +849,7 @@ static int create_device(struct zram *zram, int device_id)
pr_warn("Error creating sysfs group");
goto out_free_disk;
}
-
+ strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor));
zram->meta = NULL;
zram->max_comp_streams = 1;
return 0;
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index ccf36d11755a..7f21c145e317 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -101,5 +101,6 @@ struct zram {
u64 disksize; /* bytes */
int max_comp_streams;
struct zram_stats stats;
+ char compressor[10];
};
#endif