Messages in this thread | | | Date | Thu, 9 Feb 2006 20:43:14 -0800 | From | Andrew Morton <> | Subject | Re: msync() behaviour broken for MS_ASYNC, revert patch? |
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Nick Piggin <nickpiggin@yahoo.com.au> wrote: > > > Secondly, consider the behaviour of the above application if it is modifying > > the same page relatively frequently (quite likely). If MS_ASYNC starts I/O > > immediately, that page will get written 10, 100 or 1000 times per second. > > If MS_ASYNC leaves it to pdflush, that page gets written once per 30 > > seconds, so we do far much less I/O. > > > > We just don't know. It's better to leave it up to the application designer > > rather than lumping too many operations into the one syscall. > > Well it remains the same conceptual operation (asynchronously "schedule" > dirty pages for writeout). However it simply becomes more useful to start > the writeout immediately, given that's the (pretty explicit) hint that is > given to us.
If you want to start the I/O now, fine, start the I/O now.
If you don't want to start I/O now, fine, don't start I/O now.
If msync() were to unconditionally start I/O, you don't get that option.
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