[lkml]   [2018]   [Dec]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] dma-debug: Kconfig for PREALLOC_DMA_DEBUG_ENTRIES
On Mon, Dec 03, 2018 at 11:56:11AM +0000, John Garry wrote:
> On 01/12/2018 16:36, Christoph Hellwig wrote:
>> On Fri, Nov 30, 2018 at 07:39:50PM +0000, Robin Murphy wrote:
>>> I was assuming the point was to also add something like
>>> default 131072 if HNS_ENET
>>> so that DMA debug doesn't require too much thought from the user. If they
>>> still have to notice the overflow message and empirically figure out a
>>> value that does work, rebuilding the kernel each time is far less
>>> convenient than simply adding "dma_debug_entries=..." to their kernel
>>> command line and rebooting, which they can do today. If they do already
>>> know up-front that the default will need overriding and what the
>>> appropriate value is, then the command line still seems seems just as
>>> convenient.
>> I'm not so fond of random drivers changing the defaults. My idea
>> was rather to have the config option so that the defconfig files for
>> the Hisilicon SOCs with this hardware could select a larger number
>> without making a total mess of the kernel configuration.
>> If we really have to we could do different defaults, but I'd still
>> much rather do this on a arch/platform basis than specific drivers.
> As I understand, some drivers could even use much more than this (131072),
> to such a point where I can't imagine that we would want to set an arch
> default to support them. For this HNS_ENET case, it is arm64 specific so it
> would be an arch defconfig.

But I'm not sure we could always do the right thing for everyone.

I think we might be better of trying to just dynamically allocate
entries when we run out of them instead of coming up with a perfect

 \ /
  Last update: 2018-12-03 18:34    [W:0.076 / U:5.156 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site