Messages in this thread | | | Date | Tue, 7 Apr 2009 09:51:31 +0200 | Subject | Re: [PATCH 0/8][RFC] IO latency/throughput fixes | From | Geert Uytterhoeven <> |
| |
On Tue, Apr 7, 2009 at 01:10, Linus Torvalds <torvalds@linux-foundation.org> wrote: > On Mon, 6 Apr 2009, Linus Torvalds wrote: >> thing that we think people would be happiest with. >> >> I think "ordered" was a reasonable default, but that was at least partly >> because _both_ ordered and writeback sucked (partly in different ways). >> >> I do think we could make it a config option. > > A patch _something_ like this. > > A few notes: > > - This is UNTESTED (of course) > > - If I did this right, this _only_ overrides the data mode if it's not > explicitly specified on disk in the superblock mount options. > > IOW, if you have done a > > tune2fs -o journal_data_ordered > > then this will _not_ override that. Only in the absense of any explicit > flags should this trigger and then make the choice be 'writeback'. > > And just to be _extra_ backwards compatible, if you really want the old > behavior, and don't want to set the ordering flag explicitly, just answer > 'y' to the EXT3_DEFAULTS_TO_ORDERED Kconfig question. > > What do people think? Anybody want to test? > > Linus > > --- > fs/ext3/Kconfig | 19 +++++++++++++++++++ > fs/ext3/super.c | 8 +++++++- > 2 files changed, 26 insertions(+), 1 deletions(-) > > diff --git a/fs/ext3/Kconfig b/fs/ext3/Kconfig > index 8e0cfe4..fb3c1a2 100644 > --- a/fs/ext3/Kconfig > +++ b/fs/ext3/Kconfig > @@ -28,6 +28,25 @@ config EXT3_FS > To compile this file system support as a module, choose M here: the > module will be called ext3. > > +config EXT3_DEFAULTS_TO_ORDERED > + bool "Default to 'data=ordered' in ext3 (legacy option)" > + depends on EXT3_FS > + help > + If a filesystem does not explicitly specify a data ordering > + mode, and the journal capability allowed it, ext3 used to > + historically default to 'data=ordered'. > + > + That was a rather unfortunate choice, because it leads to all > + kinds of latency problems, and the 'data=writeback' mode is more > + appropriate these days. > + > + You should probably always answer 'n' here, and if you really ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > + want to use 'data=ordered' mode, set it in the filesystem itself > + with 'tune2fs -o journal_data_ordered'. > + > + But if you really want to enable the legacy default, you can do > + so by answering 'y' to this question. > +
So `allmodconfig' will enable it? Is that the right thing to do, or should it be inverted?
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |