[PATCHv2 3/4] zram: rework reported to end-user zram statistics
From: Sergey Senozhatsky
Date: Wed Jan 15 2014 - 05:20:15 EST
1) Introduce ZRAM_ATTR_RO macro to generate zram atomic64_t stats
`show' functions and reduce code duplication.
2) Remove `good' and `bad' compressed sub-requests stats. RW request may
cause a number of RW sub-requests. zram used to account `good' compressed
sub-queries (with compressed size less than 50% of original size), `bad'
compressed sub-queries (with compressed size greater that 75% of original
size), leaving sub-requests with compression size between 50% and 75% of
original size not accounted and not reported. zram already accounts each
sub-request's compression size so we can calculate real device compression
ratio.
Acked-by: Minchan Kim <minchan@xxxxxxxxxx>
Acked-by: Jerome Marchand <jmarchan@xxxxxxxxxx>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 163 ++++++++++++------------------------------
drivers/block/zram/zram_drv.h | 17 ++---
2 files changed, 51 insertions(+), 129 deletions(-)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index b0bcb7e..6eb2155 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -42,6 +42,17 @@ static struct zram *zram_devices;
/* Module params (documentation at end) */
static unsigned int num_devices = 1;
+#define ZRAM_ATTR_RO(name) \
+static ssize_t zram_attr_##name##_show(struct device *d, \
+ struct device_attribute *attr, char *b) \
+{ \
+ struct zram *zram = dev_to_zram(d); \
+ return sprintf(b, "%llu\n", \
+ (u64)atomic64_read(&zram->stats.name)); \
+} \
+static struct device_attribute dev_attr_##name = \
+ __ATTR(name, S_IRUGO, zram_attr_##name##_show, NULL);
+
static inline int init_done(struct zram *zram)
{
return zram->meta != NULL;
@@ -52,97 +63,36 @@ static inline struct zram *dev_to_zram(struct device *dev)
return (struct zram *)dev_to_disk(dev)->private_data;
}
-static ssize_t disksize_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- struct zram *zram = dev_to_zram(dev);
-
- return sprintf(buf, "%llu\n", zram->disksize);
-}
-
-static ssize_t initstate_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- struct zram *zram = dev_to_zram(dev);
-
- return sprintf(buf, "%u\n", init_done(zram));
-}
-
-static ssize_t num_reads_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- struct zram *zram = dev_to_zram(dev);
-
- return sprintf(buf, "%llu\n",
- (u64)atomic64_read(&zram->stats.num_reads));
-}
-
-static ssize_t num_writes_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- struct zram *zram = dev_to_zram(dev);
-
- return sprintf(buf, "%llu\n",
- (u64)atomic64_read(&zram->stats.num_writes));
-}
-
-static ssize_t invalid_io_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- struct zram *zram = dev_to_zram(dev);
-
- return sprintf(buf, "%llu\n",
- (u64)atomic64_read(&zram->stats.invalid_io));
-}
-
-static ssize_t notify_free_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- struct zram *zram = dev_to_zram(dev);
-
- return sprintf(buf, "%llu\n",
- (u64)atomic64_read(&zram->stats.notify_free));
-}
-
-static ssize_t zero_pages_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- struct zram *zram = dev_to_zram(dev);
-
- return sprintf(buf, "%u\n", atomic_read(&zram->stats.pages_zero));
-}
-
-static ssize_t orig_data_size_show(struct device *dev,
+static ssize_t memory_used_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
+ u64 val = 0;
struct zram *zram = dev_to_zram(dev);
+ struct zram_meta *meta = zram->meta;
- return sprintf(buf, "%llu\n",
- (u64)(atomic_read(&zram->stats.pages_stored)) << PAGE_SHIFT);
+ down_read(&zram->init_lock);
+ if (init_done(zram))
+ val = zs_get_total_size_bytes(meta->mem_pool);
+ up_read(&zram->init_lock);
+ return sprintf(buf, "%llu\n", val);
}
-static ssize_t compr_data_size_show(struct device *dev,
+static ssize_t disksize_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct zram *zram = dev_to_zram(dev);
-
- return sprintf(buf, "%llu\n",
- (u64)atomic64_read(&zram->stats.compr_size));
+ return sprintf(buf, "%llu\n", zram->disksize);
}
-static ssize_t mem_used_total_show(struct device *dev,
+static ssize_t initstate_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- u64 val = 0;
+ u32 val = 0;
struct zram *zram = dev_to_zram(dev);
- struct zram_meta *meta = zram->meta;
-
down_read(&zram->init_lock);
- if (init_done(zram))
- val = zs_get_total_size_bytes(meta->mem_pool);
+ val = init_done(zram);
up_read(&zram->init_lock);
-
- return sprintf(buf, "%llu\n", val);
+ return sprintf(buf, "%u\n", val);
}
/* flag operations needs meta->tb_lock */
@@ -293,7 +243,6 @@ static void zram_free_page(struct zram *zram, size_t index)
{
struct zram_meta *meta = zram->meta;
unsigned long handle = meta->table[index].handle;
- u16 size = meta->table[index].size;
if (unlikely(!handle)) {
/*
@@ -302,21 +251,15 @@ static void zram_free_page(struct zram *zram, size_t index)
*/
if (zram_test_flag(meta, index, ZRAM_ZERO)) {
zram_clear_flag(meta, index, ZRAM_ZERO);
- atomic_dec(&zram->stats.pages_zero);
+ atomic64_dec(&zram->stats.pages_zero);
}
return;
}
- if (unlikely(size > max_zpage_size))
- atomic_dec(&zram->stats.bad_compress);
-
zs_free(meta->mem_pool, handle);
- if (size <= PAGE_SIZE / 2)
- atomic_dec(&zram->stats.good_compress);
-
- atomic64_sub(meta->table[index].size, &zram->stats.compr_size);
- atomic_dec(&zram->stats.pages_stored);
+ atomic64_sub(meta->table[index].size, &zram->stats.compressed_size);
+ atomic64_dec(&zram->stats.pages_stored);
meta->table[index].handle = 0;
meta->table[index].size = 0;
@@ -459,7 +402,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
zram_set_flag(meta, index, ZRAM_ZERO);
write_unlock(&zram->meta->tb_lock);
- atomic_inc(&zram->stats.pages_zero);
+ atomic64_inc(&zram->stats.pages_zero);
ret = 0;
goto out;
}
@@ -478,7 +421,6 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
}
if (unlikely(clen > max_zpage_size)) {
- atomic_inc(&zram->stats.bad_compress);
clen = PAGE_SIZE;
src = NULL;
if (is_partial_io(bvec))
@@ -516,11 +458,8 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
write_unlock(&zram->meta->tb_lock);
/* Update stats */
- atomic64_add(clen, &zram->stats.compr_size);
- atomic_inc(&zram->stats.pages_stored);
- if (clen <= PAGE_SIZE / 2)
- atomic_inc(&zram->stats.good_compress);
-
+ atomic64_add(clen, &zram->stats.compressed_size);
+ atomic64_inc(&zram->stats.pages_stored);
out:
if (locked)
mutex_unlock(&meta->buffer_lock);
@@ -583,23 +522,8 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity)
static void zram_init_device(struct zram *zram, struct zram_meta *meta)
{
- if (zram->disksize > 2 * (totalram_pages << PAGE_SHIFT)) {
- pr_info(
- "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.\n"
- "\tMemory Size: %lu kB\n"
- "\tSize you selected: %llu kB\n"
- "Continuing anyway ...\n",
- (totalram_pages << PAGE_SHIFT) >> 10, zram->disksize >> 10
- );
- }
-
/* zram devices sort of resembles non-rotational disks */
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue);
-
zram->meta = meta;
pr_debug("Initialization done!\n");
}
@@ -771,14 +695,15 @@ static DEVICE_ATTR(disksize, S_IRUGO | S_IWUSR,
disksize_show, disksize_store);
static DEVICE_ATTR(initstate, S_IRUGO, initstate_show, NULL);
static DEVICE_ATTR(reset, S_IWUSR, NULL, reset_store);
-static DEVICE_ATTR(num_reads, S_IRUGO, num_reads_show, NULL);
-static DEVICE_ATTR(num_writes, S_IRUGO, num_writes_show, NULL);
-static DEVICE_ATTR(invalid_io, S_IRUGO, invalid_io_show, NULL);
-static DEVICE_ATTR(notify_free, S_IRUGO, notify_free_show, NULL);
-static DEVICE_ATTR(zero_pages, S_IRUGO, zero_pages_show, NULL);
-static DEVICE_ATTR(orig_data_size, S_IRUGO, orig_data_size_show, NULL);
-static DEVICE_ATTR(compr_data_size, S_IRUGO, compr_data_size_show, NULL);
-static DEVICE_ATTR(mem_used_total, S_IRUGO, mem_used_total_show, NULL);
+static DEVICE_ATTR(memory_used, S_IRUGO, memory_used_show, NULL);
+
+ZRAM_ATTR_RO(num_reads);
+ZRAM_ATTR_RO(num_writes);
+ZRAM_ATTR_RO(pages_stored);
+ZRAM_ATTR_RO(invalid_io);
+ZRAM_ATTR_RO(notify_free);
+ZRAM_ATTR_RO(pages_zero);
+ZRAM_ATTR_RO(compressed_size);
static struct attribute *zram_disk_attrs[] = {
&dev_attr_disksize.attr,
@@ -786,12 +711,12 @@ static struct attribute *zram_disk_attrs[] = {
&dev_attr_reset.attr,
&dev_attr_num_reads.attr,
&dev_attr_num_writes.attr,
+ &dev_attr_pages_stored.attr,
&dev_attr_invalid_io.attr,
&dev_attr_notify_free.attr,
- &dev_attr_zero_pages.attr,
- &dev_attr_orig_data_size.attr,
- &dev_attr_compr_data_size.attr,
- &dev_attr_mem_used_total.attr,
+ &dev_attr_pages_zero.attr,
+ &dev_attr_compressed_size.attr,
+ &dev_attr_memory_used.attr,
NULL,
};
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index e81e9cd..277023d 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -64,22 +64,19 @@ enum zram_pageflags {
struct table {
unsigned long handle;
u16 size; /* object size (excluding header) */
- u8 count; /* object ref count (not yet used) */
- u8 flags;
+ u16 flags;
} __aligned(4);
struct zram_stats {
- atomic64_t compr_size; /* compressed size of pages stored */
- atomic64_t num_reads; /* failed + successful */
- atomic64_t num_writes; /* --do-- */
- atomic64_t failed_reads; /* should NEVER! happen */
+ atomic64_t num_writes; /* number of writes */
+ atomic64_t num_reads; /* number of reads */
+ atomic64_t pages_stored; /* no. of pages currently stored */
+ atomic64_t compressed_size; /* compressed size of pages stored */
+ atomic64_t pages_zero; /* no. of zero filled pages */
+ atomic64_t failed_reads; /* no. of failed reads */
atomic64_t failed_writes; /* can happen when memory is too low */
atomic64_t invalid_io; /* non-page-aligned I/O requests */
atomic64_t notify_free; /* no. of swap slot free notifications */
- atomic_t pages_zero; /* no. of zero filled pages */
- atomic_t pages_stored; /* no. of pages currently stored */
- atomic_t good_compress; /* % of pages with compression ratio<=50% */
- atomic_t bad_compress; /* % of pages with compression ratio>=75% */
};
struct zram_meta {
--
1.8.5.3.493.gb139ac2
--
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