From e899007a5e10084649f558593f7e8f26088492fc Mon Sep 17 00:00:00 2001
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Date: Mon, 2 Sep 2024 19:56:12 +0900
Subject: [PATCH] zram: support priority parameter in recompression
recompress device attribute supports alg=NAME parameter so that we can
specify only one particular algorithm we want to perform recompression
with. However, with algo params we now can have several exactly same
secondary algorithms but each with its own params tuning (e.g. priority 1
configured to use more aggressive level, and priority 2 configured to use
a pre-trained dictionary). Support priority=NUM parameter so that we can
correctly determine which secondary algorithm we want to use.
Link: https://lkml.kernel.org/r/20240902105656.1383858-25-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
Documentation/admin-guide/blockdev/zram.rst | 5 ++++-
drivers/block/zram/zram_drv.c | 12 ++++++++++++
2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/blockdev/zram.rst b/Documentation/admin-guide/blockdev/zram.rst
index d3b6762735280..678d70d6e1c3a 100644
--- a/Documentation/admin-guide/blockdev/zram.rst
+++ b/Documentation/admin-guide/blockdev/zram.rst
@@ -512,11 +512,14 @@ registered compression algorithms, increases our chances of finding the
algorithm that successfully compresses a particular page. Sometimes, however,
it is convenient (and sometimes even necessary) to limit recompression to
only one particular algorithm so that it will not try any other algorithms.
-This can be achieved by providing a algo=NAME parameter:::
+This can be achieved by providing a `algo` or `priority` parameter:::
#use zstd algorithm only (if registered)
echo "type=huge algo=zstd" > /sys/block/zramX/recompress
+ #use zstd algorithm only (if zstd was registered under priority 1)
+ echo "type=huge priority=1" > /sys/block/zramX/recompress
+
memory tracking
===============
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 9b29f9e6cb503..1f1bf175a6c34 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1855,6 +1855,18 @@ static ssize_t recompress_store(struct device *dev,
algo = val;
continue;
}
+
+ if (!strcmp(param, "priority")) {
+ ret = kstrtouint(val, 10, &prio);
+ if (ret)
+ return ret;
+
+ if (prio == ZRAM_PRIMARY_COMP)
+ prio = ZRAM_SECONDARY_COMP;
+
+ prio_max = min(prio + 1, ZRAM_MAX_COMPS);
+ continue;
+ }
}
if (threshold >= huge_class_size)
--
GitLab