FUJITA Tomonori wrote: > On Wed, 02 Apr 2008 11:43:21 +0300 > Boaz Harrosh <bharrosh@xxxxxxxxxxx> wrote: > >> On Wed, Apr 02 2008 at 6:37 +0300, FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> wrote: >>> On Mon, 17 Mar 2008 22:34:22 +0100 >>> Andi Kleen <andi@xxxxxxxxxxxxxx> wrote: >>> >>>>> Look further down in the email, queue_bounce_to_mask() or whatever you >>>>> would want to call it. As also written there, the PRINCIPLE is the same. >>>>> And that is that exporting a to_allocator_mask() helper is a lot saner >>>>> than exporting an allocator api tied to the queue. >>>>> >>>>> Can we get over this, please? >>>> Ok it would have helped if you had explained why it is saner, but I >>>> bow to your superior experience on block layer issues. >>>> >>>> The only open issue is right now if it isn't better to go back >>>> for automatic bouncing for SCSI scan and the other users. Do you >>>> have an opinion on that too? If you have one can you please convince >>>> James of it too. >>> There are other things that don't want the automatic bouncing; sg, st, >>> and osst. >>> >>> Your patches remove unchecked_isa_dma in them and Boaz said that they >>> are fine since they get bounced anyway, however, it's not correct. >>> >>> As Doug said in another thread (about your patch to change GFP_ATOMIC >>> to GFP_KERNEL in sg), they try to avoid waiting for a long time and >>> want an early failure (though they are not complete; can't avoid non >>> unchecked_isa_dma bouncing) . >>> >>> We can change the bounce path in that way, but I think it's better if >>> they can allocate memory that will not get bounced. >> I was looking in blk_queue_bounce (in mm/bounce.c) and have not seen any >> case of q->bounce_gfp with __GFP_WAIT. Are you sure we are waiting for >> the bounce buffers? It will take few more CPU cycles, but I don't see >> where it will sleep. > > Hmm, q->bounce_gfp is GFP_NOIO or (GFP_NOIO | __GFP_DMA). And > __blk_queue_bounce also allocates bio with GFP_NOIO. So the bounce > path always use __GFP_WAIT. OK, Thanks, GFP_NOIO is __GFP_WAIT I didn't realize that. Any way in my new patchset we do not use bouncing and we use the new mask allocator so every one should be happy. Boaz -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
