zram: add recompress flag to read_block_state()

Add a new flag to zram block state that shows if the page was recompressed
(using alternative compression algorithm).

Link: https://lkml.kernel.org/r/20221109115047.2921851-6-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Alexey Romanov <avromanov@sberdevices.ru>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/Documentation/admin-guide/blockdev/zram.rst b/Documentation/admin-guide/blockdev/zram.rst
index c73b169..177a142 100644 (file)
--- a/Documentation/admin-guide/blockdev/zram.rst
+++ b/Documentation/admin-guide/blockdev/zram.rst
@@ -411,9 +411,10 @@ pages of the process with*pagemap.
 If you enable the feature, you could see block state via
 /sys/kernel/debug/zram/zram0/block_state". The output is as follows::
 
-         300    75.033841 .wh.
-         301    63.806904 s...
-         302    63.806919 ..hi
+         300    75.033841 .wh..
+         301    63.806904 s....
+         302    63.806919 ..hi.
+         303    62.801919 ....r
 
 First column
        zram's block index.
@@ -430,6 +431,8 @@ Third column
                huge page
        i:
                idle page
+       r:
+               recompressed page (secondary compression algorithm)
 
 First line of above example says 300th block is accessed at 75.033841sec
 and the block's state is huge so it is written back to the backing

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 97300b3..ddbfa70 100644 (file)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -936,13 +936,14 @@ static ssize_t read_block_state(struct file *file, char __user *buf,
 
                ts = ktime_to_timespec64(zram->table[index].ac_time);
                copied = snprintf(kbuf + written, count,
-                       "%12zd %12lld.%06lu %c%c%c%c\n",
+                       "%12zd %12lld.%06lu %c%c%c%c%c\n",
                        index, (s64)ts.tv_sec,
                        ts.tv_nsec / NSEC_PER_USEC,
                        zram_test_flag(zram, index, ZRAM_SAME) ? 's' : '.',
                        zram_test_flag(zram, index, ZRAM_WB) ? 'w' : '.',
                        zram_test_flag(zram, index, ZRAM_HUGE) ? 'h' : '.',
-                       zram_test_flag(zram, index, ZRAM_IDLE) ? 'i' : '.');
+                       zram_test_flag(zram, index, ZRAM_IDLE) ? 'i' : '.',
+                       zram_get_priority(zram, index) ? 'r' : '.');
 
                if (count <= copied) {
                        zram_slot_unlock(zram, index);