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

Tao Liu
2026-04-14T10:28:00Z

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