On Thu, May 03, 2018 at 02:03:38PM +0200, Michal Hocko wrote:
> On Sat 28-04-18 19:10:47, Matthew Wilcox wrote:
> > Another way we could approach this is to get rid of ZONE_DMA. Make GFP_DMA
> > a flag which doesn't map to a zone. Rather, it redirects to a separate
> > allocator. At boot, we hand a
On Sat 28-04-18 19:10:47, Matthew Wilcox wrote:
> Another way we could approach this is to get rid of ZONE_DMA. Make GFP_DMA
> a flag which doesn't map to a zone. Rather, it redirects to a separate
> allocator. At boot, we hand all memory under 16MB to the DMA allocator. The
> DMA allocator can hav
Hi Luis,
On Thu, Apr 26, 2018 at 11:54 PM, Luis R. Rodriguez wrote:
> x86 implicit and explicit ZONE_DMA users
> -
>
> We list below all x86 implicit and explicit ZONE_DMA users.
>
> # Explicit x86 users of GFP_DMA or __GFP_DMA
>
> * drivers/iio/common/ss
Here are some improved results, also taking into account the pci
functions.
julia
too small: drivers/gpu/drm/i915/i915_drv.c:1138: 30
too small: drivers/hwtracing/coresight/coresight-tmc.c:335: 0
too small: drivers/media/pci/sta2x11/sta2x11_vip.c:859: 29
too small: drivers/media/pci/sta2x11/sta2x
On Sat, Apr 28, 2018 at 09:46:52PM +0200, Julia Lawall wrote:
> FWIW, here is my semantic patch and the output - it reports on things that
> appear to be too small and things that it doesn't know about.
>
> What are the relevant pci wrappers? I didn't find them.
Basically all of the functions in
On Sat, 28 Apr 2018, Luis R. Rodriguez wrote:
> On Sat, Apr 28, 2018 at 01:42:21AM -0700, Christoph Hellwig wrote:
> > On Fri, Apr 27, 2018 at 04:14:56PM +, Luis R. Rodriguez wrote:
> > > Do we have a list of users for x86 with a small DMA mask?
> > > Or, given that I'm not aware of a tool t
On Sat, Apr 28, 2018 at 01:42:21AM -0700, Christoph Hellwig wrote:
> On Fri, Apr 27, 2018 at 04:14:56PM +, Luis R. Rodriguez wrote:
> > Do we have a list of users for x86 with a small DMA mask?
> > Or, given that I'm not aware of a tool to be able to look
> > for this in an easy way, would it b
On Fri, Apr 27, 2018 at 04:14:56PM +, Luis R. Rodriguez wrote:
> But curious, on a standard qemu x86_x64 KVM guest, which of the
> drivers do we know for certain *are* being used from the ones
> listed?
On a KVM guest probably none. But not all the world is relatively
sane and standardized VM
On Fri, Apr 27, 2018 at 11:36:23AM -0500, Christopher Lameter wrote:
> On Fri, 27 Apr 2018, Matthew Wilcox wrote:
>
> > Some devices have incredibly bogus hardware like 28 bit addressing
> > or 39 bit addressing. We don't have a good way to allocate memory by
> > physical address other than than
On Fri, Apr 27, 2018 at 11:07:07AM -0500, Christopher Lameter wrote:
> Well it looks like what we are using it for is to force allocation from
> low physical memory if we fail to obtain proper memory through a normal
> channel. The use of ZONE_DMA is only there for emergency purposes.
> I think we
On Fri, Apr 27, 2018 at 09:18:43AM +0200, Michal Hocko wrote:
> > On Thu, Apr 26, 2018 at 09:54:06PM +, Luis R. Rodriguez wrote:
> > > In practice if you don't have a floppy device on x86, you don't need
> > > ZONE_DMA,
> >
> > I call BS on that, and you actually explain later why it it BS du
On Fri 27-04-18 11:07:07, Cristopher Lameter wrote:
> On Fri, 27 Apr 2018, Michal Hocko wrote:
>
> > On Thu 26-04-18 22:35:56, Christoph Hellwig wrote:
> > > On Thu, Apr 26, 2018 at 09:54:06PM +, Luis R. Rodriguez wrote:
> > > > In practice if you don't have a floppy device on x86, you don't n
On Fri, 27 Apr 2018, Matthew Wilcox wrote:
> Some devices have incredibly bogus hardware like 28 bit addressing
> or 39 bit addressing. We don't have a good way to allocate memory by
> physical address other than than saying "GFP_DMA for anything less than
> 32, GFP_DMA32 (or GFP_KERNEL on 32-bit
On Fri, Apr 27, 2018 at 04:14:56PM +, Luis R. Rodriguez wrote:
> > Not really. We have unchecked_isa_dma to support about 4 drivers,
>
> Ah very neat:
>
> * CONFIG_CHR_DEV_OSST - "SCSI OnStream SC-x0 tape support"
That's an upper level driver, like cdrom, disk and regular tapes.
> * CO
On Fri, Apr 27, 2018 at 11:07:07AM -0500, Christopher Lameter wrote:
> Well it looks like what we are using it for is to force allocation from
> low physical memory if we fail to obtain proper memory through a normal
> channel. The use of ZONE_DMA is only there for emergency purposes.
> I think we
On Fri, 27 Apr 2018, Michal Hocko wrote:
> On Thu 26-04-18 22:35:56, Christoph Hellwig wrote:
> > On Thu, Apr 26, 2018 at 09:54:06PM +, Luis R. Rodriguez wrote:
> > > In practice if you don't have a floppy device on x86, you don't need
> > > ZONE_DMA,
> >
> > I call BS on that, and you actual
On Thu, Apr 26, 2018 at 10:35:56PM -0700, Christoph Hellwig wrote:
> On Thu, Apr 26, 2018 at 09:54:06PM +, Luis R. Rodriguez wrote:
> > In practice if you don't have a floppy device on x86, you don't need
> > ZONE_DMA,
>
> I call BS on that,
I did not explain though that it was not me who c
On Thu 26-04-18 22:35:56, Christoph Hellwig wrote:
> On Thu, Apr 26, 2018 at 09:54:06PM +, Luis R. Rodriguez wrote:
> > In practice if you don't have a floppy device on x86, you don't need
> > ZONE_DMA,
>
> I call BS on that, and you actually explain later why it it BS due
> to some drivers u
On Thu, Apr 26, 2018 at 09:54:06PM +, Luis R. Rodriguez wrote:
> In practice if you don't have a floppy device on x86, you don't need ZONE_DMA,
I call BS on that, and you actually explain later why it it BS due
to some drivers using it more explicitly. But even more importantly
we have plenty
On Thu, 2018-04-26 at 21:54 +, Luis R. Rodriguez wrote:
> Below are my notes on the ZONE_DMA discussion at LSF/MM 2018. There
> were some
> earlier discussion prior to my arrival to the session about moving
> around
> ZOME_DMA around, if someone has notes on that please share too :)
We took no
Below are my notes on the ZONE_DMA discussion at LSF/MM 2018. There were some
earlier discussion prior to my arrival to the session about moving around
ZOME_DMA around, if someone has notes on that please share too :)
PS. I'm not subscribed to linux-mm
Luis
Determining you don't need to suppor
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