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zram: add recompression algorithm sysfs knob

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Introduce recomp_algorithm sysfs knob that controls secondary algorithm
selection used for recompression.

We will support up to 3 secondary compression algorithms which are sorted
in order of their priority.  To select an algorithm user has to provide
its name and priority:

  echo "algo=zstd priority=1" > /sys/block/zramX/recomp_algorithm
  echo "algo=deflate priority=2" > /sys/block/zramX/recomp_algorithm

During recompression zram iterates through the list of registered
secondary algorithms in order of their priorities.

We also have a short version for cases when there is only
one secondary compression algorithm:

  echo "algo=zstd" > /sys/block/zramX/recomp_algorithm

This will register zstd as the secondary algorithm with priority 1.

Link: https://lkml.kernel.org/r/20221109115047.2921851-3-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Alexey Romanov <avromanov@sberdevices.ru>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Sergey Senozhatsky 2022-11-09 20:50:36 +09:00 committed by Andrew Morton
parent 7ac07a26de
commit 001d927357
1 changed files with 105 additions and 19 deletions
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124
drivers/block/zram/zram_drv.c
View File

@ -997,31 +997,28 @@ 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)
static void comp_algorithm_set(struct zram *zram, u32 prio, const char *alg)
{
size_t sz;
struct zram *zram = dev_to_zram(dev);
/* Do not free statically defined compression algorithms */
if (zram->comp_algs[prio] != default_compressor)
kfree(zram->comp_algs[prio]);
zram->comp_algs[prio] = alg;
}
static ssize_t __comp_algorithm_show(struct zram *zram, u32 prio, char *buf)
{
ssize_t sz;
down_read(&zram->init_lock);
sz = zcomp_available_show(zram->comp_algs[ZRAM_PRIMARY_COMP], buf);
sz = zcomp_available_show(zram->comp_algs[prio], buf);
up_read(&zram->init_lock);
return sz;
}
static void comp_algorithm_set(struct zram *zram, u32 prio, const char *alg)
static int __comp_algorithm_store(struct zram *zram, u32 prio, const char *buf)
{
/* Do not kfree() algs that we didn't allocate, IOW the default ones */
if (zram->comp_algs[prio] != default_compressor)
kfree(zram->comp_algs[prio]);
zram->comp_algs[prio] = alg;
}
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);
char *compressor;
size_t sz;
@ -1050,11 +1047,94 @@ static ssize_t comp_algorithm_store(struct device *dev,
return -EBUSY;
}
comp_algorithm_set(zram, ZRAM_PRIMARY_COMP, compressor);
comp_algorithm_set(zram, prio, compressor);
up_write(&zram->init_lock);
return len;
return 0;
}
static ssize_t comp_algorithm_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct zram *zram = dev_to_zram(dev);
return __comp_algorithm_show(zram, ZRAM_PRIMARY_COMP, buf);
}
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);
int ret;
ret = __comp_algorithm_store(zram, ZRAM_PRIMARY_COMP, buf);
return ret ? ret : len;
}
#ifdef CONFIG_ZRAM_MULTI_COMP
static ssize_t recomp_algorithm_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct zram *zram = dev_to_zram(dev);
ssize_t sz = 0;
u32 prio;
for (prio = ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
if (!zram->comp_algs[prio])
continue;
sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, "#%d: ", prio);
sz += __comp_algorithm_show(zram, prio, buf + sz);
}
return sz;
}
static ssize_t recomp_algorithm_store(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
struct zram *zram = dev_to_zram(dev);
int prio = ZRAM_SECONDARY_COMP;
char *args, *param, *val;
char *alg = NULL;
int ret;
args = skip_spaces(buf);
while (*args) {
args = next_arg(args, &param, &val);
if (!*val)
return -EINVAL;
if (!strcmp(param, "algo")) {
alg = val;
continue;
}
if (!strcmp(param, "priority")) {
ret = kstrtoint(val, 10, &prio);
if (ret)
return ret;
continue;
}
}
if (!alg)
return -EINVAL;
if (prio < ZRAM_SECONDARY_COMP || prio >= ZRAM_MAX_COMPS)
return -EINVAL;
ret = __comp_algorithm_store(zram, prio, alg);
return ret ? ret : len;
}
#endif
static ssize_t compact_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
@ -1895,6 +1975,9 @@ static DEVICE_ATTR_WO(writeback);
static DEVICE_ATTR_RW(writeback_limit);
static DEVICE_ATTR_RW(writeback_limit_enable);
#endif
#ifdef CONFIG_ZRAM_MULTI_COMP
static DEVICE_ATTR_RW(recomp_algorithm);
#endif
static struct attribute *zram_disk_attrs[] = {
&dev_attr_disksize.attr,
@ -1918,6 +2001,9 @@ static struct attribute *zram_disk_attrs[] = {
&dev_attr_bd_stat.attr,
#endif
&dev_attr_debug_stat.attr,
#ifdef CONFIG_ZRAM_MULTI_COMP
&dev_attr_recomp_algorithm.attr,
#endif
NULL,
};
@ -1997,7 +2083,7 @@ static int zram_add(void)
if (ret)
goto out_cleanup_disk;
zram->comp_algs[ZRAM_PRIMARY_COMP] = default_compressor;
comp_algorithm_set(zram, ZRAM_PRIMARY_COMP, default_compressor);
zram_debugfs_register(zram);
pr_info("Added device: %s\n", zram->disk->disk_name);