linux-kernel - [PATCHv4 7/9] zram: Add recompress flag to read_block

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Message-Id: <20221018045533.2396670-8-senozhatsky@chromium.org>
Date:   Tue, 18 Oct 2022 13:55:31 +0900
From:   Sergey Senozhatsky <senozhatsky@...omium.org>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Minchan Kim <minchan@...nel.org>
Cc:     Nitin Gupta <ngupta@...are.org>, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, Sergey Senozhatsky <senozhatsky@...omium.org>
Subject: [PATCHv4 7/9] 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).

Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>
---
 Documentation/admin-guide/blockdev/zram.rst | 9 ++++++---
 drivers/block/zram/zram_drv.c               | 5 +++--
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/Documentation/admin-guide/blockdev/zram.rst b/Documentation/admin-guide/blockdev/zram.rst
index c916c2b9da55..010fb05a5999 100644
--- a/Documentation/admin-guide/blockdev/zram.rst
+++ b/Documentation/admin-guide/blockdev/zram.rst
@@ -466,9 +466,10 @@ 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.
@@ -485,6 +486,8 @@ 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 1e9561217466..5d760467e0bc 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -925,13 +925,14 @@ 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_test_flag(zram, index, ZRAM_RECOMP) ? 'r' : '.');
 
 		if (count <= copied) {
 			zram_slot_unlock(zram, index);
-- 
2.38.0.413.g74048e4d9e-goog