On 10/28/2014 12:57 PM, Michal Nazarewicz wrote: >> On 10/28/2014 08:38 AM, Michal Nazarewicz wrote: >>> Like Laura wrote, the message is not (should not be) a problem in >>> itself: >> >> [...] >> >>> So as you can see cma_alloc will try another part of the cma region if >>> test_pages_isolated fails. >>> >>> Obviously, if CMA region is fragmented or there's enough space for only >>> one allocation of required size isolation failures will cause allocation >>> failures, so it's best to avoid them, but they are not always avoidable. >>> >>> To debug you would probably want to add more debug information about the >>> page (i.e. data from struct page) that failed isolation after the >>> pr_warn in alloc_contig_range. > > On Tue, Oct 28 2014, Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> wrote: >> If the message does not indicate an actual problem, then its printk level is >> too high. These messages have been reported when using 3.16+ distro kernels. > > I think it could be argued both ways. The condition is not an error, > since in many cases cma_alloc will be able to continue, but it *is* an > undesired state. As such it's not an error but feels to me a bit more > then just information, hence a warning. I don't care either way, though. This "undesired state" is trivially reproducible on 3.16.y on the x86 arch; a smattering of these will show up just building a distro kernel. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>