On 09.05.2017 13:34, Andrew Turner wrote: >> On 9 May 2017, at 12:05, Michal Meloun <[email protected]> wrote: >> >> Author: mmel >> Date: Tue May 9 11:05:32 2017 >> New Revision: 318021 >> URL: https://svnweb.freebsd.org/changeset/base/318021 >> >> Log: >> Introduce pmap_remap_vm_attr(), >> it allows to remap one VM memattr class to another. >> >> This function is intent to be used as workaround for various SoC bugs, >> mainly access ordering/sequencing related bugs in crossbar fabric. > This seems quite heavy handed to change the attribute for all memory of a > given type. Yes, exactly. See comment in D10218 - /* * Workaround for Marvell Armada38X family HW issue * between Cortex-A9 CPUs and on-chip devices that may * cause hang on heavy load. * To avoid that, map all registers including PCIe IO * as strongly ordered instead of device memory. */
> Other architectures have pmap_change_attr to change the attribute on a > specific range of memory. Right. Problem is that I don't known any method how we can change memory attribute for live memory in SMP system, without hitting undefined behavior. Michal _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "[email protected]"
