Hello Dave, From: Dave Anderson <anderson@xxxxxxxxxx> Subject: Re: [RFC] makedumpfile, crash: LZO compression support Date: Thu, 17 Nov 2011 13:25:31 -0500 (EST) > > > ----- Original Message ----- >> Hello, >> >> This is a RFC patch set that adds LZO compression support to >> makedumpfile and crash utility. LZO is as good as in size but by far >> better in speed than ZLIB, leading to reducing down time during >> generation of crash dump and refiltering. >> >> How to build: >> >> 1. Get LZO library, which is provided as lzo-devel package on recent >> linux distributions, and is also available on author's website: >> http://www.oberhumer.com/opensource/lzo/. >> >> 2. Apply the patch set to makedumpfile v1.4.0 and crash v6.0.0. >> >> 3. Build both using make. But for crash, do the following now: >> >> $ make CFLAGS="-llzo2" >> >> How to use: >> >> I've newly used -l option for lzo compression in this patch. So for >> example, do as follows: >> >> $ makedumpfile -l vmcore dumpfile >> $ crash vmlinux dumpfile >> >> Request of configure-like feature for crash utility: >> >> I would like configure-like feature on crash utility for users to >> select wheather to add LZO feature actually or not in build-time, >> that is: ./configure --enable-lzo or ./configure --disable-lzo. >> >> The reason is that support staff often downloads and installs the >> latest version of crash utility on machines where lzo library is not >> provided. > > Right, at least on Fedora, these three packages would need to be installed: > > lzo-2.06-1.fc15.x86_64 > lzo-minilzo-2.06-1.fc15.x86_64 > lzo-devel-2.06-1.fc15.x86_64 > >> >> Looking at the source code, it looks to me that crash does some kind >> of configuration processing in a local manner, around configure.c, >> and I guess it's difficult to use autoconf tools directly. >> >> Or is there another better way? > > Instead of using CFLAGS, it would be preferable to dynamically append "-llzo2" to > the string that the gdb_merge stanza in the Makefile writes to the "mergelibs" > file here: > > gdb_merge: force > @if [ ! -f ${GDB}/README ]; then \ > make --no-print-directory gdb_unzip; fi > ===> @echo "${LDFLAGS} -lz -ldl -rdynamic" > ${GDB}/gdb/mergelibs > @echo "../../${PROGRAM} ../../${PROGRAM}lib.a" > ${GDB}/gdb/mergeobj > @if [ ! -f ${GDB}/config.status ]; then \ > (cd ${GDB}; ./configure ${GDB_CONF_FLAGS} --with-separate-debug-dir=/usr/lib/debug \ > --with-bugurl="" --with-expat=no --with-python=no; \ > make --no-print-directory; echo ${TARGET} > crash.target) \ > else (cd ${GDB}/gdb; make --no-print-directory;); fi > @if [ ! -f ${GDB}/gdb/libgdb.a ]; then \ > echo; echo "gdb build failed: ${GDB}/gdb/libgdb.a does not exist"; \ > echo; exit 1; fi > > It also requires an additional #define so that the #include line in defs.h > and the calls to lzo_init() and lzo1x_decompress_safe() in diskdump.c can > be encapsulated, i.e., something like: > > #ifdef LZO > #include <lzo/lzo1x.h> > #endif > > #ifdef LZO > dd->lzo_supported = lzo_init() == LZO_E_OK; > #endif > > #ifdef LZO > ret = lzo1x_decompress_safe(dd->compressed_page, pd.size, > dd->page_cache_hdr[i].pg_bufptr, > &retlen, LZO1X_MEM_DECOMPRESS); > #endif > > The -DLZO would only need to be passed to the diskump.c compile line. > > This could involve configure.c, but conceivably it could all be done within the > Makefile itself. For example, by entering something like "make compress=lzo2", > and then adding this to the Makefile: > > ifneq ($(compress),) > ifeq ($(compress), lzo2) > LZOFLAG=-DLZO > LZOLIB=-llzo2 > endif > endif > > And then the diskdump.c compile line could use ${LZOFLAG}, and the > gdb_merge stanza could include ${LZOLIB}. > Thanks for accepting the request and for detailed instructions. I'll reflect these configuration logic in the next patch. Thanks. HATAYAMA, Daisuke -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/crash-utility
