1) Extend zram_comp zcomp_create() with `num_wm' parameter.
`num_wm' limits the number of workmem structs in compression
backend's idle list (max buffers).
2) Introduce zram device attribute max_buffers to show and
store current device's zram_comp max number (num_wm) of workmems.
Usage example:
echo 4 > /sys/block/zram0/max_buffers
set max_buffers to 4
cat /sys/block/zram0/max_buffers
show current max_buffers (default value is 1).
iozone -t -T -R -l 3 -u 3 -r 16K -s 60M -I +Z
(write tests. ext4, lzo, each test performed on newly created
zram0 device)
test max_buffers 1 max_buffers 3
---------------------------------------------------
" Initial write " 631583.39 | 727834.88
" Rewrite " 456248.23 | 2105054.97
" Mixed workload " 3370016.43 | 3509382.86
" Random write " 467703.56 | 1953464.78
" Pwrite " 629146.88 | 775372.46
" Fwrite " 2573117.39 | 2529637.62
test max_buffers 1 max_buffers 3
---------------------------------------------------
" Initial write " 601112.91 | 765866.05
" Rewrite " 447834.33 | 2163449.58
" Mixed workload " 2575128.08 | 3257711.77
" Random write " 461327.45 | 1974731.12
" Pwrite " 567038.36 | 740242.52
" Fwrite " 2527107.44 | 2754336.64
Signed-off-by: Sergey Senozhatsky <sergey.senozhat...@gmail.com>
---
drivers/block/zram/zram_comp.c | 15 +++++++++------
drivers/block/zram/zram_comp.h | 2 +-
drivers/block/zram/zram_drv.c | 42 +++++++++++++++++++++++++++++++++++++++++-
drivers/block/zram/zram_drv.h | 2 +-
4 files changed, 52 insertions(+), 9 deletions(-)
diff --git a/drivers/block/zram/zram_comp.c b/drivers/block/zram/zram_comp.c
index 139a468..d9b34ba 100644
--- a/drivers/block/zram/zram_comp.c
+++ b/drivers/block/zram/zram_comp.c
@@ -118,11 +118,12 @@ static struct zram_comp_backend *find_backend(const char
*compress)
* allocate new zram_comp and initialize it. return NULL
* if requested algorithm is not supported or in case
* of init error */
-struct zram_comp *zcomp_create(const char *compress)
+struct zram_comp *zcomp_create(const char *compress, int num_wm)
{
struct zram_comp *comp;
struct zram_comp_backend *backend;
struct zcomp_workmem *wm;
+ int i;
backend = find_backend(compress);
if (!backend)
@@ -137,11 +138,13 @@ struct zram_comp *zcomp_create(const char *compress)
INIT_LIST_HEAD(&comp->idle_workmem);
init_waitqueue_head(&comp->workmem_wait);
- wm = workmem_alloc(comp);
- if (!wm) {
- zcomp_destroy(comp);
- return NULL;
+ for (i = 0; i < num_wm; i++) {
+ wm = workmem_alloc(comp);
+ if (!wm) {
+ zcomp_destroy(comp);
+ return NULL;
+ }
+ list_add_tail(&wm->list, &comp->idle_workmem);
}
- list_add_tail(&wm->list, &comp->idle_workmem);
return comp;
}
diff --git a/drivers/block/zram/zram_comp.h b/drivers/block/zram/zram_comp.h
index 90355e8..277afa0 100644
--- a/drivers/block/zram/zram_comp.h
+++ b/drivers/block/zram/zram_comp.h
@@ -43,7 +43,7 @@ struct zram_comp {
struct zram_comp_backend *backend;
};
-struct zram_comp *zcomp_create(const char *comp);
+struct zram_comp *zcomp_create(const char *comp, int num_wm);
void zcomp_destroy(struct zram_comp *comp);
struct zcomp_workmem *zcomp_workmem_get(struct zram_comp *comp);
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 4875a16..a065c1b 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -107,6 +107,41 @@ static ssize_t mem_used_total_show(struct device *dev,
return sprintf(buf, "%llu\n", val);
}
+static ssize_t max_buffers_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ long val;
+ struct zram *zram = dev_to_zram(dev);
+
+ down_read(&zram->init_lock);
+ val = zram->max_buffers;
+ up_read(&zram->init_lock);
+
+ return sprintf(buf, "%ld\n", val);
+}
+
+static ssize_t max_buffers_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ long num;
+ struct zram *zram = dev_to_zram(dev);
+
+ if (kstrtol(buf, 0, &num))
+ return -EINVAL;
+ if (num < 1 || num > 100)
+ return -EINVAL;
+ down_write(&zram->init_lock);
+ if (init_done(zram)) {
+ up_write(&zram->init_lock);
+ pr_info("Cannot set max buffers for initialized device\n");
+ return -EBUSY;
+ }
+ zram->max_buffers = 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)
@@ -505,6 +540,7 @@ static void zram_reset_device(struct zram *zram, bool
reset_capacity)
if (zram->comp)
zcomp_destroy(zram->comp);
zram->comp = NULL;
+ zram->max_buffers = 1;
zram_meta_free(zram->meta);
zram->meta = NULL;
@@ -534,7 +570,7 @@ static ssize_t disksize_store(struct device *dev,
return -EBUSY;
}
- zram->comp = zcomp_create(default_compressor);
+ zram->comp = zcomp_create(default_compressor, zram->max_buffers);
if (!zram->comp) {
up_write(&zram->init_lock);
pr_info("Cannot initialise compressing backend\n");
@@ -697,6 +733,8 @@ 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_buffers, S_IRUGO | S_IWUSR,
+ max_buffers_show, max_buffers_store);
ZRAM_ATTR_RO(num_reads);
ZRAM_ATTR_RO(num_writes);
@@ -721,6 +759,7 @@ 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_buffers.attr,
NULL,
};
@@ -784,6 +823,7 @@ static int create_device(struct zram *zram, int device_id)
zram->meta = NULL;
zram->comp = NULL;
+ zram->max_buffers = 1;
return 0;
out_free_disk:
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index a2e17d7..68a5421 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -99,7 +99,7 @@ struct zram {
* we can store in a disk.
*/
u64 disksize; /* bytes */
-
+ long max_buffers;
struct zram_stats stats;
};
#endif
--
1.9.0.rc3.244.g3497008
--
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