Messages in this thread | | | Date | Fri, 4 Dec 2009 14:17:33 -0800 | From | Randy Dunlap <> | Subject | Re: [PATCH] page-types: kernel pageflags mode |
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On Fri, 04 Dec 2009 14:29:48 -0700 Alex Chiang wrote:
> An earlier commit taught page-types the -d|--describe argument, which > allows the user to describe page flags passed on the command line: > > # ./Documentation/vm/page-types -d 0x4000 > 0x0000000000004000 ______________b___________________ swapbacked > > In -d mode, page-types expects the page flag bits in the order generated > by the kernel function get_uflags(). > > However, those bits are rearranged compared to what is actually stored > in struct page->flags. A kernel developer dumping a page's flags > using printk, e.g., may get misleading results in -d mode. > > Teach page-types the -k mode, which parses and describes the bits in > the internal kernel order: > > # ./Documentation/vm/page-types -k 0x4000 > 0x0000000000004000 ______________H_________ compound_head > > Note that the recommended way to build page-types is from the top-level > kernel source directory. This ensures that it will get the same CONFIG_* > defines used to build the kernel source. > > # make Documentation/vm/ > > The implication is that attempting to use page-types -k on a kernel > with different CONFIG_* settings may lead to surprising and misleading > results. To retain sanity, always use the page-types built out of the > kernel tree you are actually testing. > > Cc: fengguang.wu@intel.com > Cc: Haicheng Li <haicheng.li@intel.com> > Cc: Andi Kleen <andi@firstfloor.org> > Cc: Randy Dunlap <randy.dunlap@oracle.com> > Signed-off-by: Alex Chiang <achiang@hp.com> > --- > > Applies on top of mmotm. > > Documentation/vm/Makefile | 2 + > Documentation/vm/page-types.c | 117 +++++++++++++++++++++++++++++++++++++++-- > 2 files changed, 113 insertions(+), 6 deletions(-) > > diff --git a/Documentation/vm/Makefile b/Documentation/vm/Makefile > index 5bd269b..1bebc43 100644 > --- a/Documentation/vm/Makefile > +++ b/Documentation/vm/Makefile > @@ -1,6 +1,8 @@ > # kbuild trick to avoid linker error. Can be omitted if a module is built. > obj- := dummy.o > > +HOSTCFLAGS_page-types.o += $(LINUXINCLUDE) > + > # List of programs to build > hostprogs-y := slabinfo page-types
I can ack the Makefile part. Thanks for the patch.
Not that I expect this patch to change for this, but I think that we need to move tools (like this one) from Documentation/ to tools/ and possibly move examples from Documentation/ to samples/ or tools/.
--- ~Randy
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