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path: root/drivers/block/zram/zram_drv.c
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Diffstat (limited to 'drivers/block/zram/zram_drv.c')
-rw-r--r--drivers/block/zram/zram_drv.c104
1 files changed, 64 insertions, 40 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 370c2f760..8fcad8b76 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -304,46 +304,25 @@ static ssize_t mem_used_max_store(struct device *dev,
return len;
}
+/*
+ * We switched to per-cpu streams and this attr is not needed anymore.
+ * However, we will keep it around for some time, because:
+ * a) we may revert per-cpu streams in the future
+ * b) it's visible to user space and we need to follow our 2 years
+ * retirement rule; but we already have a number of 'soon to be
+ * altered' attrs, so max_comp_streams need to wait for the next
+ * layoff cycle.
+ */
static ssize_t max_comp_streams_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- int val;
- struct zram *zram = dev_to_zram(dev);
-
- down_read(&zram->init_lock);
- val = zram->max_comp_streams;
- up_read(&zram->init_lock);
-
- return scnprintf(buf, PAGE_SIZE, "%d\n", val);
+ return scnprintf(buf, PAGE_SIZE, "%d\n", num_online_cpus());
}
static ssize_t max_comp_streams_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
- int num;
- struct zram *zram = dev_to_zram(dev);
- int ret;
-
- ret = kstrtoint(buf, 0, &num);
- if (ret < 0)
- return ret;
- if (num < 1)
- return -EINVAL;
-
- down_write(&zram->init_lock);
- if (init_done(zram)) {
- if (!zcomp_set_max_streams(zram->comp, num)) {
- pr_info("Cannot change max compression streams\n");
- ret = -EINVAL;
- goto out;
- }
- }
-
- zram->max_comp_streams = num;
- ret = len;
-out:
- up_write(&zram->init_lock);
- return ret;
+ return len;
}
static ssize_t comp_algorithm_show(struct device *dev,
@@ -456,8 +435,26 @@ static ssize_t mm_stat_show(struct device *dev,
return ret;
}
+static ssize_t debug_stat_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int version = 1;
+ struct zram *zram = dev_to_zram(dev);
+ ssize_t ret;
+
+ down_read(&zram->init_lock);
+ ret = scnprintf(buf, PAGE_SIZE,
+ "version: %d\n%8llu\n",
+ version,
+ (u64)atomic64_read(&zram->stats.writestall));
+ up_read(&zram->init_lock);
+
+ return ret;
+}
+
static DEVICE_ATTR_RO(io_stat);
static DEVICE_ATTR_RO(mm_stat);
+static DEVICE_ATTR_RO(debug_stat);
ZRAM_ATTR_RO(num_reads);
ZRAM_ATTR_RO(num_writes);
ZRAM_ATTR_RO(failed_reads);
@@ -514,7 +511,7 @@ static struct zram_meta *zram_meta_alloc(char *pool_name, u64 disksize)
goto out_error;
}
- meta->mem_pool = zs_create_pool(pool_name, GFP_NOIO | __GFP_HIGHMEM);
+ meta->mem_pool = zs_create_pool(pool_name);
if (!meta->mem_pool) {
pr_err("Error creating memory pool\n");
goto out_error;
@@ -650,7 +647,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
{
int ret = 0;
size_t clen;
- unsigned long handle;
+ unsigned long handle = 0;
struct page *page;
unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
struct zram_meta *meta = zram->meta;
@@ -673,9 +670,8 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
goto out;
}
- zstrm = zcomp_strm_find(zram->comp);
+compress_again:
user_mem = kmap_atomic(page);
-
if (is_partial_io(bvec)) {
memcpy(uncmem + offset, user_mem + bvec->bv_offset,
bvec->bv_len);
@@ -699,6 +695,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
goto out;
}
+ zstrm = zcomp_strm_find(zram->comp);
ret = zcomp_compress(zram->comp, zstrm, uncmem, &clen);
if (!is_partial_io(bvec)) {
kunmap_atomic(user_mem);
@@ -710,6 +707,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
pr_err("Compression failed! err=%d\n", ret);
goto out;
}
+
src = zstrm->buffer;
if (unlikely(clen > max_zpage_size)) {
clen = PAGE_SIZE;
@@ -717,8 +715,35 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
src = uncmem;
}
- handle = zs_malloc(meta->mem_pool, clen);
+ /*
+ * handle allocation has 2 paths:
+ * a) fast path is executed with preemption disabled (for
+ * per-cpu streams) and has __GFP_DIRECT_RECLAIM bit clear,
+ * since we can't sleep;
+ * b) slow path enables preemption and attempts to allocate
+ * the page with __GFP_DIRECT_RECLAIM bit set. we have to
+ * put per-cpu compression stream and, thus, to re-do
+ * the compression once handle is allocated.
+ *
+ * if we have a 'non-null' handle here then we are coming
+ * from the slow path and handle has already been allocated.
+ */
+ if (!handle)
+ handle = zs_malloc(meta->mem_pool, clen,
+ __GFP_KSWAPD_RECLAIM |
+ __GFP_NOWARN |
+ __GFP_HIGHMEM);
if (!handle) {
+ zcomp_strm_release(zram->comp, zstrm);
+ zstrm = NULL;
+
+ atomic64_inc(&zram->stats.writestall);
+
+ handle = zs_malloc(meta->mem_pool, clen,
+ GFP_NOIO | __GFP_HIGHMEM);
+ if (handle)
+ goto compress_again;
+
pr_err("Error allocating memory for compressed page: %u, size=%zu\n",
index, clen);
ret = -ENOMEM;
@@ -1009,7 +1034,6 @@ static void zram_reset_device(struct zram *zram)
/* Reset stats */
memset(&zram->stats, 0, sizeof(zram->stats));
zram->disksize = 0;
- zram->max_comp_streams = 1;
set_capacity(zram->disk, 0);
part_stat_set_all(&zram->disk->part0, 0);
@@ -1038,7 +1062,7 @@ static ssize_t disksize_store(struct device *dev,
if (!meta)
return -ENOMEM;
- comp = zcomp_create(zram->compressor, zram->max_comp_streams);
+ comp = zcomp_create(zram->compressor);
if (IS_ERR(comp)) {
pr_err("Cannot initialise %s compressing backend\n",
zram->compressor);
@@ -1177,6 +1201,7 @@ static struct attribute *zram_disk_attrs[] = {
&dev_attr_comp_algorithm.attr,
&dev_attr_io_stat.attr,
&dev_attr_mm_stat.attr,
+ &dev_attr_debug_stat.attr,
NULL,
};
@@ -1273,7 +1298,6 @@ static int zram_add(void)
}
strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor));
zram->meta = NULL;
- zram->max_comp_streams = 1;
pr_info("Added device: %s\n", zram->disk->disk_name);
return device_id;