Messages in this thread | | | Date | Wed, 30 Jul 2014 12:19:20 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 0/2] new API to allocate buffer-cache for superblock in non-movable area |
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On Wed, Jul 30, 2014 at 12:11:43PM +0200, Jan Kara wrote: > > sb_bread allocates page from movable area but it is not movable until the > > reference counter of the buffer-head becomes zero. > > There is no lock for the buffer but the reference counter acts like lock. > OK, but why do you care about a single page (of at most handful if you > have more filesystems) which isn't movable? That shouldn't make a big > difference to compaction...
The thing is, CMA _must_ be able to clear all the pages in its range, otherwise its broken.
So placing nonmovable pages in a movable block utterly wrecks that.
Now, Ted said that there's more effectively pinned stuff from filesystems (and I imagine those would be things like the root inode etc.) and those would equally wreck this..
But Gioh didn't mention any of that.. he should I suppose. [unhandled content-type:application/pgp-signature] | |