Messages in this thread | | | Date | Mon, 23 Jan 2006 22:02:22 +0100 | From | Jens Axboe <> | Subject | Re: [PATCH 1/2][RESEND] Default iosched fixes (was: Fall back io scheduler for 2.6.15?) |
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On Mon, Jan 23 2006, Nate Diller wrote: > On 1/21/06, Jens Axboe <axboe@suse.de> wrote: > > On Fri, Jan 20 2006, Nate Diller wrote: > > > My previous default iosched patch did a poor job dealing with the > > > 'elevator=' boot-time option. The old behavior falls back to the > > > compiled-in default if the requested one is not registered at boot > > > time. This patch dynamically evaluates which default > > > to use, and emits a suitable error message when the requested scheduler > > > is not available. It also does the 'as' -> 'anticipatory' conversion > > > before elevator registration, which along with a modified registration > > > function, allows it to correctly indicate which default scheduler is > > > in use. > > > > I'm a little confused by your description - what problem does this patch > > actually solve? We already fall back to the default, and we already do > > the "as" conversion. It does seem to cleanup the code, just curious > > since your description seems to promise a little more than what it > > actually adds. > > It makes the ' (default)' printk that happens at elevator registration > time behave (more) correctly. My original patch rather ignored that > segment of code. The current behavior is to only print ' (default)' > when one was specified at boot time, and not if 'as' was requested > either, since it doesn't understand the 'as -> anticipatory' > conversion. Now, it will display correctly the one selected at > compile-time, if none was specified at boot, and when the boot-time > option was 'as'. > > It also handles modular defaults better; although they cannot be > specified in kconfig, a default requested at boot-time will now still > work, even if it's a module. When the boot-time requested scheduler > is not loaded, it will fall back to the compiled-in default; when it > is, it gets used.
Ok, thanks for the (better) explanation. I'll add your patch for inclusion, thanks.
-- Jens Axboe
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