Messages in this thread | | | Date | Fri, 19 Nov 2010 10:06:41 -0500 | From | Christoph Hellwig <> | Subject | Re: [PATCH 3/3] mlock: avoid dirtying pages and triggering writeback |
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On Fri, Nov 19, 2010 at 08:42:05AM -0500, Theodore Tso wrote: > My vote would be against. ? If you if you mmap a sparse file and then > try writing to it willy-nilly, bad things will happen. ?This is true without > a mlock(). ? Where is it written that mlock() has anything to do with > improving this situation?
Exactly. Allocating space has been a side-effect on a handfull filesystem for about 20 kernel releases.
> If userspace wants to call fallocate() before it calls mlock(), it should > do that. ?And in fact, in most cases, userspace should probably be > encouraged to do that. ? But having mlock() call fallocate() and > then return ENOSPC if there's no room? Isn't it confusing that mlock() > call ENOSPC? Doesn't that give you cognitive dissonance? It should > because fundamentally mlock() has nothing to do with block allocation!! > Read the API spec!
Indeed. There is no need to make mlock + flag a parallel-API to fallocate.
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