diff --git a/Documentation/btrfs-man5.asciidoc b/Documentation/btrfs-man5.asciidoc
index 6a1a04b7..3b8a9672 100644
--- a/Documentation/btrfs-man5.asciidoc
+++ b/Documentation/btrfs-man5.asciidoc
@@ -125,10 +125,10 @@ The upper bound is not forced, but a warning is printed if it's more than 300
 seconds (5 minutes). Use with care.
 
 *compress*::
-*compress='type'*::
+*compress='type[:level]'*::
 *compress-force*::
-*compress-force='type'*::
-(default: off)
+*compress-force='type[:level]'*::
+(default: off, level support since: 5.1)
 +
 Control BTRFS file data compression.  Type may be specified as 'zlib',
 'lzo', 'zstd' or 'no' (for no compression, used for remounting).  If no type
@@ -136,6 +136,13 @@ is specified, 'zlib' is used.  If 'compress-force' is specified,
 then compression will always be attempted, but the data may end up uncompressed
 if the compression would make them larger.
 +
+Both 'zlib' and 'zstd' (since version 5.1) expose the compression level as a
+tunable knob with higher levels trading speed and memory ('zstd') for higher
+compression ratios. This can be set by appending a colon and the desired level.
+Zlib accepts the range [1, 9] and zstd accepts [1, 15]. If no level is set,
+both currently use a default level of 3. The value 0 is an alias for the defaul
+level.
++
 Otherwise some simple heuristics are applied to detect an incompressible file.
 If the first blocks written to a file are not compressible, the whole file is
 permanently marked to skip compression. As this is too simple, the