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authorMinchan Kim <minchan@kernel.org>2014-10-09 15:29:55 -0700
committerAlex Shi <alex.shi@linaro.org>2015-05-11 21:23:25 +0800
commitcda6b06454ce34ec784cc45c427eb4b0131581e1 (patch)
tree7e6c7d5f55ef08a8f6d0f9749856ed19a815a446
parent3c854b64635888527504dfc898687ab10dad6191 (diff)
downloadlinux-linaro-stable-cda6b06454ce34ec784cc45c427eb4b0131581e1.tar.gz
zram: report maximum used memory
Normally, zram user could get maximum memory usage zram consumed via polling mem_used_total with sysfs in userspace. But it has a critical problem because user can miss peak memory usage during update inverval of polling. For avoiding that, user should poll it with shorter interval(ie, 0.0000000001s) with mlocking to avoid page fault delay when memory pressure is heavy. It would be troublesome. This patch adds new knob "mem_used_max" so user could see the maximum memory usage easily via reading the knob and reset it via "echo 0 > /sys/block/zram0/mem_used_max". Signed-off-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Dan Streetman <ddstreet@ieee.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: <juno.choi@lge.com> Cc: <seungho1.park@lge.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Seth Jennings <sjennings@variantweb.net> Reviewed-by: David Horner <ds2horner@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> (cherry picked from commit 461a8eee6af3b55745be64bea403ed0b743563cf) Signed-off-by: Alex Shi <alex.shi@linaro.org>
-rw-r--r--Documentation/ABI/testing/sysfs-block-zram10
-rw-r--r--Documentation/blockdev/zram.txt1
-rw-r--r--drivers/block/zram/zram_drv.c60
-rw-r--r--drivers/block/zram/zram_drv.h1
4 files changed, 70 insertions, 2 deletions
diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram
index f861cbfab6b1..31db44f01936 100644
--- a/Documentation/ABI/testing/sysfs-block-zram
+++ b/Documentation/ABI/testing/sysfs-block-zram
@@ -128,6 +128,16 @@ Description:
statistic.
Unit: bytes
+What: /sys/block/zram<id>/mem_used_max
+Date: August 2014
+Contact: Minchan Kim <minchan@kernel.org>
+Description:
+ The mem_used_max file is read/write and specifies the amount
+ of maximum memory zram have consumed to store compressed data.
+ For resetting the value, you should write "0". Otherwise,
+ you could see -EINVAL.
+ Unit: bytes
+
What: /sys/block/zram<id>/mem_limit
Date: August 2014
Contact: Minchan Kim <minchan@kernel.org>
diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt
index 4331ebf94bf0..5cd0bd903f54 100644
--- a/Documentation/blockdev/zram.txt
+++ b/Documentation/blockdev/zram.txt
@@ -110,6 +110,7 @@ size of the disk when not in use so a huge zram is wasteful.
orig_data_size
compr_data_size
mem_used_total
+ mem_used_max
8) Deactivate:
swapoff /dev/zram0
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 3f4da06c89c0..204b7fa9d78e 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -153,6 +153,41 @@ static ssize_t mem_limit_store(struct device *dev,
return len;
}
+static ssize_t mem_used_max_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ u64 val = 0;
+ struct zram *zram = dev_to_zram(dev);
+
+ down_read(&zram->init_lock);
+ if (init_done(zram))
+ val = atomic_long_read(&zram->stats.max_used_pages);
+ up_read(&zram->init_lock);
+
+ return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT);
+}
+
+static ssize_t mem_used_max_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ int err;
+ unsigned long val;
+ struct zram *zram = dev_to_zram(dev);
+ struct zram_meta *meta = zram->meta;
+
+ err = kstrtoul(buf, 10, &val);
+ if (err || val != 0)
+ return -EINVAL;
+
+ down_read(&zram->init_lock);
+ if (init_done(zram))
+ atomic_long_set(&zram->stats.max_used_pages,
+ zs_get_total_pages(meta->mem_pool));
+ up_read(&zram->init_lock);
+
+ return len;
+}
+
static ssize_t max_comp_streams_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
@@ -464,6 +499,21 @@ out_cleanup:
return ret;
}
+static inline void update_used_max(struct zram *zram,
+ const unsigned long pages)
+{
+ int old_max, cur_max;
+
+ old_max = atomic_long_read(&zram->stats.max_used_pages);
+
+ do {
+ cur_max = old_max;
+ if (pages > cur_max)
+ old_max = atomic_long_cmpxchg(
+ &zram->stats.max_used_pages, cur_max, pages);
+ } while (old_max != cur_max);
+}
+
static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
int offset)
{
@@ -475,6 +525,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
struct zram_meta *meta = zram->meta;
struct zcomp_strm *zstrm;
bool locked = false;
+ unsigned long alloced_pages;
page = bvec->bv_page;
if (is_partial_io(bvec)) {
@@ -544,13 +595,15 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
goto out;
}
- if (zram->limit_pages &&
- zs_get_total_pages(meta->mem_pool) > zram->limit_pages) {
+ alloced_pages = zs_get_total_pages(meta->mem_pool);
+ if (zram->limit_pages && alloced_pages > zram->limit_pages) {
zs_free(meta->mem_pool, handle);
ret = -ENOMEM;
goto out;
}
+ update_used_max(zram, alloced_pages);
+
cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO);
if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) {
@@ -899,6 +952,8 @@ 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(mem_limit, S_IRUGO | S_IWUSR, mem_limit_show,
mem_limit_store);
+static DEVICE_ATTR(mem_used_max, S_IRUGO | S_IWUSR, mem_used_max_show,
+ mem_used_max_store);
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,
@@ -928,6 +983,7 @@ static struct attribute *zram_disk_attrs[] = {
&dev_attr_compr_data_size.attr,
&dev_attr_mem_used_total.attr,
&dev_attr_mem_limit.attr,
+ &dev_attr_mem_used_max.attr,
&dev_attr_max_comp_streams.attr,
&dev_attr_comp_algorithm.attr,
NULL,
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index b7aa9c21553f..c6ee271317f5 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -90,6 +90,7 @@ struct zram_stats {
atomic64_t notify_free; /* no. of swap slot free notifications */
atomic64_t zero_pages; /* no. of zero filled pages */
atomic64_t pages_stored; /* no. of pages currently stored */
+ atomic_long_t max_used_pages; /* no. of maximum pages stored */
};
struct zram_meta {