Messages in this thread | | | From | Bill Davidsen <> | Subject | Re: [PATCH 00/23] per device dirty throttling -v8 | Date | Thu, 09 Aug 2007 20:21:22 -0400 |
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Andrew Morton wrote: > On Wed, 08 Aug 2007 14:10:15 -0700 > "Martin J. Bligh" <mbligh@mbligh.org> wrote: > >> Why isn't this easily fixable by just adding an additional dirty >> flag that says atime has changed? Then we only cause a write >> when we remove the inode from the inode cache, if only atime >> is updated. > > I think that could be made to work, and it would fix the performance > issue. > > It is a behaviour change. At present ext3 (for example) commits everything > every five seconds. After a change like this, a crash+recovery could cause > a file's atime to go backwards by an arbitrarily large time interval - it > could easily be months. > I would think that (really) updating atime on open would be enough, hopefully without being too much. The "lazyatime" thing I was playing with only updated on open, final close, write, and fork.
I like the idea of updating once in a while, but one of the benefits of noatime is allowing drives to spin down via inactivity. If something does get done in the area of less but non-zero atime tracking, perhaps that could be taken into account. I have to check what "laptop_mode actually does, since my laptops are old installs.
-- Bill Davidsen <davidsen@tmr.com> "We have more to fear from the bungling of the incompetent than from the machinations of the wicked." - from Slashdot
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