The patch titled Subject: zram: add bd_stat statistics has been added to the -mm tree. Its filename is zram-add-bd_stat-statistics.patch
This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/zram-add-bd_stat-statistics.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/zram-add-bd_stat-statistics.patch
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------------------------------------------------------ From: Minchan Kim minchan@kernel.org Subject: zram: add bd_stat statistics
bd_stat represents things that happened in the backing device. Currently it supports bd_counts, bd_reads and bd_writes which are helpful to understand wearout of flash and memory saving.
Link: http://lkml.kernel.org/r/20181127055429.251614-7-minchan@kernel.org Signed-off-by: Minchan Kim minchan@kernel.org Cc: Joey Pabalinas joeypabalinas@gmail.com Cc: Sergey Senozhatsky sergey.senozhatsky.work@gmail.com Cc: stable@vger.kernel.org [4.14+] Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
Documentation/ABI/testing/sysfs-block-zram | 8 +++++ Documentation/blockdev/zram.txt | 11 +++++++ drivers/block/zram/zram_drv.c | 29 +++++++++++++++++++ drivers/block/zram/zram_drv.h | 5 +++ 4 files changed, 53 insertions(+)
--- a/Documentation/ABI/testing/sysfs-block-zram~zram-add-bd_stat-statistics +++ a/Documentation/ABI/testing/sysfs-block-zram @@ -113,3 +113,11 @@ Contact: Minchan Kim <minchan@kernel.org Description: The writeback file is write-only and trigger idle and/or huge page writeback to backing device. + +What: /sys/block/zram<id>/bd_stat +Date: November 2018 +Contact: Minchan Kim minchan@kernel.org +Description: + The bd_stat file is read-only and represents backing device's + statistics (bd_count, bd_reads, bd_writes) in a format + similar to block layer statistics file format. --- a/Documentation/blockdev/zram.txt~zram-add-bd_stat-statistics +++ a/Documentation/blockdev/zram.txt @@ -221,6 +221,17 @@ line of text and contains the following pages_compacted the number of pages freed during compaction huge_pages the number of incompressible pages
+File /sys/block/zram<id>/bd_stat + +The stat file represents device's backing device statistics. It consists of +a single line of text and contains the following stats separated by whitespace: + bd_count size of data written in backing device. + Unit: 4K bytes + bd_reads the number of reads from backing device + Unit: 4K bytes + bd_writes the number of writes to backing device + Unit: 4K bytes + 9) Deactivate: swapoff /dev/zram0 umount /dev/zram1 --- a/drivers/block/zram/zram_drv.c~zram-add-bd_stat-statistics +++ a/drivers/block/zram/zram_drv.c @@ -502,6 +502,7 @@ retry: if (test_and_set_bit(blk_idx, zram->bitmap)) goto retry;
+ atomic64_inc(&zram->stats.bd_count); return blk_idx; }
@@ -511,6 +512,7 @@ static void free_block_bdev(struct zram
was_set = test_and_clear_bit(blk_idx, zram->bitmap); WARN_ON_ONCE(!was_set); + atomic64_dec(&zram->stats.bd_count); }
static void zram_page_end_io(struct bio *bio) @@ -668,6 +670,7 @@ static ssize_t writeback_store(struct de continue; }
+ atomic64_inc(&zram->stats.bd_writes); /* * We released zram_slot_lock so need to check if the slot was * changed. If there is freeing for the slot, we can catch it @@ -757,6 +760,7 @@ static int read_from_bdev_sync(struct zr static int read_from_bdev(struct zram *zram, struct bio_vec *bvec, unsigned long entry, struct bio *parent, bool sync) { + atomic64_inc(&zram->stats.bd_reads); if (sync) return read_from_bdev_sync(zram, bvec, entry, parent); else @@ -1013,6 +1017,25 @@ static ssize_t mm_stat_show(struct devic return ret; }
+#ifdef CONFIG_ZRAM_WRITEBACK +static ssize_t bd_stat_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct zram *zram = dev_to_zram(dev); + ssize_t ret; + + down_read(&zram->init_lock); + ret = scnprintf(buf, PAGE_SIZE, + "%8llu %8llu %8llu\n", + (u64)atomic64_read(&zram->stats.bd_count), + (u64)atomic64_read(&zram->stats.bd_reads), + (u64)atomic64_read(&zram->stats.bd_writes)); + up_read(&zram->init_lock); + + return ret; +} +#endif + static ssize_t debug_stat_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -1033,6 +1056,9 @@ static ssize_t debug_stat_show(struct de
static DEVICE_ATTR_RO(io_stat); static DEVICE_ATTR_RO(mm_stat); +#ifdef CONFIG_ZRAM_WRITEBACK +static DEVICE_ATTR_RO(bd_stat); +#endif static DEVICE_ATTR_RO(debug_stat);
static void zram_meta_free(struct zram *zram, u64 disksize) @@ -1759,6 +1785,9 @@ static struct attribute *zram_disk_attrs #endif &dev_attr_io_stat.attr, &dev_attr_mm_stat.attr, +#ifdef CONFIG_ZRAM_WRITEBACK + &dev_attr_bd_stat.attr, +#endif &dev_attr_debug_stat.attr, NULL, }; --- a/drivers/block/zram/zram_drv.h~zram-add-bd_stat-statistics +++ a/drivers/block/zram/zram_drv.h @@ -82,6 +82,11 @@ struct zram_stats { atomic_long_t max_used_pages; /* no. of maximum pages stored */ atomic64_t writestall; /* no. of write slow paths */ atomic64_t miss_free; /* no. of missed free */ +#ifdef CONFIG_ZRAM_WRITEBACK + atomic64_t bd_count; /* no. of pages in backing device */ + atomic64_t bd_reads; /* no. of reads from backing device */ + atomic64_t bd_writes; /* no. of writes from backing device */ +#endif };
struct zram { _
Patches currently in -mm which might be from minchan@kernel.org are
zram-fix-lockdep-warning-of-free-block-handling.patch zram-fix-double-free-backing-device.patch zram-refactoring-flags-and-writeback-stuff.patch zram-introduce-zram_idle-flag.patch zram-support-idle-huge-page-writeback.patch zram-add-bd_stat-statistics.patch zram-writeback-throttle.patch