Messages in this thread |  | | Subject | Re: Bounce buffer deadlock | Date | Sat, 30 Jun 2001 12:48:21 -0500 | From | Steve Lord <> |
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> > On Sat, 30 Jun 2001, Steve Lord wrote: > > > > It looks to me as if all memory allocations of type GFP_BUFFER which happen > > in generic_make_request downwards can hit the same type of deadlock, so > > bounce buffers, the request functions of the raid and lvm paths can all > > end up in try_to_free_buffers on a buffer they themselves hold the lock on. > > .. which is why GFP_BUFFER doesn't exist any more in the most recent > pre-kernels (oops, this is pre8 only, not pre7 like I said in the previous > email) > > The problem is that GFP_BUFFER used to mean two things: "don't call > low-level filesystem" and "don't do IO". Some of the pre-kernels starting > to make it mean "don't call low-level FS" only. The later ones split up > the semantics, so that the cases which care about FS deadlocks use > "GFP_NOFS", and the cases that care about IO recursion use "GFP_NOIO", so > that we don't overload the meaning of GFP_BUFFER. > > That allows us to do the best we can - still flushing out dirty buffers > when that's ok (like when a filesystem wants more memory), and giving the > allocator better control over exactly _what_ he objects to. > > Linus
OK, sounds reasonable, time to go download and merge again I guess!
Steve
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