[PATCH v5][makedumpfile 8/9] Doc: Add --extension option to makedumpfile manual

[Tao Liu <ltao@redhat.com>]

Suggested-by: Kazuhito Hagio <k-hagio-ab@nec.com>
Signed-off-by: Tao Liu <ltao@redhat.com>
---
 README            |  6 ++++++
 makedumpfile.8.in | 11 ++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/README b/README
index b2666cb..0f1ccb9 100644
--- a/README
+++ b/README
@@ -65,6 +65,12 @@
     # make USEZSTD=on ; make install
     The user has to prepare zstd library.
 
+  - Build with extension support:
+    # make EXTENSION=on ; make install
+    The user has to prepare bpf library with version(>=v1.4.0).
+    Note: the extension will only work for kernels with DEBUG_INFO_BTF
+    & KALLSYMS enabled.
+
   - Build the extension module for --eppic option.
     # make eppic_makedumpfile.so
     The user has to prepare eppic library from the following site:
diff --git a/makedumpfile.8.in b/makedumpfile.8.in
index 1edd0ff..5af1786 100644
--- a/makedumpfile.8.in
+++ b/makedumpfile.8.in
@@ -2,7 +2,7 @@
 .SH NAME
 makedumpfile \- make a small dumpfile of kdump
 .SH SYNOPSIS
-\fBmakedumpfile\fR    [\fIOPTION\fR] [\-x \fIVMLINUX\fR|\-i \fIVMCOREINFO\fR] \fIVMCORE\fR \fIDUMPFILE\fR
+\fBmakedumpfile\fR    [\fIOPTION\fR] [\-x \fIVMLINUX\fR|\-i \fIVMCOREINFO\fR] [--extension \fIEXTENSION1.SO\fR [--extension \fIEXTENSION2.SO\fR ..]] \fIVMCORE\fR \fIDUMPFILE\fR
 .br
 \fBmakedumpfile\fR \-F [\fIOPTION\fR] [\-x \fIVMLINUX\fR|\-i \fIVMCOREINFO\fR] \fIVMCORE\fR
 .br
@@ -664,6 +664,15 @@ This option cannot be used with the --dump-dmesg, --reassemble and -g options.
 Display report messages. This is an alternative to enabling bit 4 in the level
 provided to --message-level.
 
+.TP
+\fB\-\-extension\fR \fIEXTENSION.SO\fR
+Load makedumpfile extensions. By using extensions, users can programmably
+customize mm page keeping / discard, alone with the traditional page-flag
+(-d dump_level) based filtering. The option can be used multiple times to
+select various extensions. NOTE: this option needs EXTENSION=on when build
+makedumpfile with libbpf(>=v1.4.0). Also this option only works for kernels
+with DEBUG_INFO_BTF & KALLSYMS enabled.
+
 .SH ENVIRONMENT VARIABLES
 
 .TP 8
-- 
2.47.0