Messages in this thread | | | Date | Wed, 11 Sep 2002 19:42:26 -0700 | From | Andrew Morton <> | Subject | Re: [RFC][PATCH] sard changes for 2.5.34 |
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Rick Lindsley wrote: > > Here's a patch to put sard changes similar to those in 2.4 into 2.5. I > say "similar" because the I/O subsystem has changed sufficiently in 2.5 > that making them exactly the same might be more effort that it's > worth. Still, we do record per-partition reads/writes/sectors, and > per-disk stats on the same plus queue time and number of I/O merges. > Once applied, "cat /proc/diskstats" outputs this information.
It would be very nice to get better disk accounting into the kernel.
> Because in 2.5.34, gendisk->part[0] no longer is an hd_struct that > refers to the whole disk, there wasn't a convenient place to record > this information. I gratuitously added an hd_struct to gendisk to have > a place to store the information, below, but that's distasteful and > ugly. I'd like to move it to a different place. > > Also, with this patch, we are collecting stats twice, once for these > stats and once for /proc/stat (kstat). That's stupid and I'd like to > get the stats only once and use them, perhaps, in two places.
kstat should be a lighter-weight per-cpu thing. But the current disk accounting in there would make it 12 kilobytes per CPU.
My vote: remove the disk accounting from kernel_stat and use this.
> What follows works, but needs refinements. Comments welcome.
What are those refinements?
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