Messages in this thread | | | Date | Thu, 14 May 2009 11:40:46 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH 4/6] PM/Hibernate: Rework shrinking of memory |
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> > > > The main point (I thought) was to remove shrink_all_memory(). Instead, > > > > we're retaining it and adding even more stuff? > > > > > > The idea is that afterwards we can drop shrink_all_memory() once the > > > performance problem has been resolved. Also, we now allocate memory for the > > > image using GFP_KERNEL instead of doing it with GFP_ATOMIC after freezing > > > devices. I'd think that's an improvement? > > > > Dunno. GFP_KERNEL might attempt to do writeback/swapout/etc, which > > could be embarrassing if the devices are frozen. > > They aren't, because the preallocation is done upfront, so once the OOM killer > has been taken care of, it's totally safe. :-)
As is GFP_ATOMIC. Except that GFP_KERNEL will cause catastrophic consequences when accounting goes wrong. (New kernel's idea of what is on disk will differ from what is _really_ on disk.)
If accounting is right, GFP_ATOMIC and GFP_KERNEL is equivalent.
If accounting is wrong, GFP_ATOMIC will fail with NULL, while GFP_KERNEL will do something bad.
I'd keep GFP_ATOMIC (or GFP_NOIO or similar).
Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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