+ zram-add-incompressible-flag-to-read_block_state.patch added to mm-unstable branch

+ zram-add-incompressible-flag-to-read_block_state.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: zram: add incompressible flag to read_block_state()
has been added to the -mm mm-unstable branch.  Its filename is
     zram-add-incompressible-flag-to-read_block_state.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-add-incompressible-flag-to-read_block_state.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Subject: zram: add incompressible flag to read_block_state()
Date: Wed, 9 Nov 2022 20:50:47 +0900

Add a new flag to zram block state that shows if the page is
incompressible: that none of the algorithm (including secondary ones)
could compress it.

Link: https://lkml.kernel.org/r/20221109115047.2921851-14-senozhatsky@chromium.org
Suggested-by: Minchan Kim <minchan@kernel.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>
---

 Documentation/admin-guide/blockdev/zram.rst |   11 +++++++----
 drivers/block/zram/zram_drv.c               |    6 ++++--
 2 files changed, 11 insertions(+), 6 deletions(-)

--- a/Documentation/admin-guide/blockdev/zram.rst~zram-add-incompressible-flag-to-read_block_state
+++ a/Documentation/admin-guide/blockdev/zram.rst
@@ -497,10 +497,11 @@ 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.
-	  303    62.801919 ....r
+	  300    75.033841 .wh...
+	  301    63.806904 s.....
+	  302    63.806919 ..hi..
+	  303    62.801919 ....r.
+	  304   146.781902 ..hi.n
 
 First column
 	zram's block index.
@@ -519,6 +520,8 @@ Third column
 		idle page
 	r:
 		recompressed page (secondary compression algorithm)
+	n:
+		none (including secondary) of algorithms could compress it
 
 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
--- a/drivers/block/zram/zram_drv.c~zram-add-incompressible-flag-to-read_block_state
+++ a/drivers/block/zram/zram_drv.c
@@ -946,14 +946,16 @@ static ssize_t read_block_state(struct f
 
 		ts = ktime_to_timespec64(zram->table[index].ac_time);
 		copied = snprintf(kbuf + written, count,
-			"%12zd %12lld.%06lu %c%c%c%c%c\n",
+			"%12zd %12lld.%06lu %c%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_get_priority(zram, index) ? 'r' : '.');
+			zram_get_priority(zram, index) ? 'r' : '.',
+			zram_test_flag(zram, index,
+				       ZRAM_INCOMPRESSIBLE) ? 'n' : '.');
 
 		if (count <= copied) {
 			zram_slot_unlock(zram, index);
_

Patches currently in -mm which might be from senozhatsky@chromium.org are

zram-preparation-for-multi-zcomp-support.patch
zram-add-recompression-algorithm-sysfs-knob.patch
zram-factor-out-wb-and-non-wb-zram-read-functions.patch
zram-introduce-recompress-sysfs-knob.patch
zram-add-recompress-flag-to-read_block_state.patch
zram-clarify-writeback_store-comment.patch
zram-use-is_err_value-to-check-for-zs_malloc-errors.patch
zram-remove-redundant-checks-from-zram_recompress.patch
zram-add-algo-parameter-support-to-zram_recompress.patch
documentation-add-zram-recompression-documentation.patch
zram-add-incompressible-writeback.patch
zram-add-incompressible-flag-to-read_block_state.patch