From: Andi Kleen <andi@firstfloor.org>
To: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: andi@firstfloor.org, dgilbert@interlog.com,
James.Bottomley@HansenPartnership.com, axboe@kernel.dk,
linux-scsi@vger.kernel.org
Subject: Re: [PATCH] [13/21] Use blk_q_mask/get_pages_mask in sg driver
Date: Mon, 17 Nov 2008 12:23:46 +0100 [thread overview]
Message-ID: <20081117112346.GI6703@one.firstfloor.org> (raw)
In-Reply-To: <20081117200720M.fujita.tomonori@lab.ntt.co.jp>
> > I would rather prefer to fix the driver to always GFP_DMA, but I am
> > not aware of any driver who needs it. Are you?
>
> Well, theoretically, there migth be an user who want these ioctl with
> all the drivers that are not capable of 64bit DMA since sg allocates
> the reserved buffer with GFP_KERNEL. These driver might use the
> block-layer bounce buffer. Users might want to use
> SG_SET_FORCE_LOW_DMA to avoid the bounce buffer latency.
But that would force everything through the 16MB zone,
putting a lot of pressure on it and might even overflow on some
loads. I don't think that's a good strategy for any application.
-Andi
--
ak@linux.intel.com
next prev parent reply other threads:[~2008-11-17 11:14 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-15 23:11 [PATCH] [0/21] Remove isa_unchecked_dma and some more GFP_DMAs in the mid layer v5 Andi Kleen
2008-11-15 23:11 ` [PATCH] [1/21] Add the alloc/get_pages_mask calls Andi Kleen
2008-11-15 23:11 ` [PATCH] [2/21] Add blk_q_mask Andi Kleen
2008-11-16 14:21 ` James Bottomley
2008-11-16 17:40 ` Theodore Tso
2008-11-16 22:19 ` Andi Kleen
2008-11-15 23:11 ` [PATCH] [3/21] Pass gfp to scsi_allocate_command Andi Kleen
2008-11-16 15:29 ` James Bottomley
2008-11-16 22:21 ` Andi Kleen
2008-11-15 23:11 ` [PATCH] [4/21] Add sense_buffer_isa to host template Andi Kleen
2008-11-15 23:11 ` [PATCH] [5/21] Remove unchecked_isa in BusLogic Andi Kleen
2008-11-16 15:46 ` James Bottomley
2008-11-16 22:31 ` Andi Kleen
2008-11-17 11:03 ` James Bottomley
2008-11-15 23:11 ` [PATCH] [6/21] Remove unchecked_isa_dma in advansys.c Andi Kleen
2008-11-16 16:56 ` James Bottomley
2008-11-16 22:33 ` Andi Kleen
2008-11-17 11:32 ` James Bottomley
2008-11-15 23:11 ` [PATCH] [7/21] Remove unchecked_isa_dma in gdth Andi Kleen
2008-11-15 23:11 ` [PATCH] [8/21] Remove unchecked_isa_dma in eata.c Andi Kleen
2008-11-15 23:11 ` [PATCH] [9/21] Remove unchecked_isa_dma in aha1542 Andi Kleen
2008-11-15 23:11 ` [PATCH] [10/21] Remove unchecked_isa_dma in aha152x/wd7000/sym53c416/u14-34f/NCR53c406a Andi Kleen
2008-11-15 23:11 ` [PATCH] [11/21] Remove GFP_DMA uses in st/osst Andi Kleen
2008-11-15 23:11 ` [PATCH] [12/21] Remove unchecked_isa_dma support for hostdata Andi Kleen
2008-11-15 23:11 ` [PATCH] [13/21] Use blk_q_mask/get_pages_mask in sg driver Andi Kleen
2008-11-16 2:11 ` Douglas Gilbert
2008-11-16 22:17 ` Andi Kleen
2008-11-17 5:11 ` FUJITA Tomonori
2008-11-17 10:22 ` Andi Kleen
2008-11-17 11:07 ` FUJITA Tomonori
2008-11-17 11:23 ` Andi Kleen [this message]
2008-11-17 11:22 ` FUJITA Tomonori
2008-11-17 11:43 ` Andi Kleen
2008-11-17 11:47 ` FUJITA Tomonori
2008-11-15 23:11 ` [PATCH] [14/21] Rely on block layer bouncing for ISA DMA devices scanning Andi Kleen
2008-11-15 23:11 ` [PATCH] [15/21] Don't disable direct_io for unchecked_isa_dma in st.c Andi Kleen
2008-11-15 23:11 ` [PATCH] [16/21] Remove automatic block layer bouncing for unchecked_isa_dma Andi Kleen
2008-11-15 23:11 ` [PATCH] [17/21] Remove GFP_DMA use in sr.c Andi Kleen
2008-11-15 23:11 ` [PATCH] [18/21] Remove unchecked_isa_dma from sysfs Andi Kleen
2008-11-15 23:11 ` [PATCH] [19/21] Switch to a single SCSI command pool Andi Kleen
2008-11-15 23:11 ` [PATCH] [20/21] Finally kill unchecked_isa_dma Andi Kleen
2008-11-15 23:11 ` [PATCH] [21/21] Convert DMA buffers in ch.c to allocate via the block layer Andi Kleen
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