> On 04 Aug 2015, at 19:46 , Jason A. Harmening <j...@freebsd.org> wrote: > > Author: jah > Date: Tue Aug 4 19:46:13 2015 > New Revision: 286296 > URL: https://svnweb.freebsd.org/changeset/base/286296 > > Log: > Add two new pmap functions: > vm_offset_t pmap_quick_enter_page(vm_page_t m) > void pmap_quick_remove_page(vm_offset_t kva) > > These will create and destroy a temporary, CPU-local KVA mapping of a > specified page. > > Guarantees: > --Will not sleep and will not fail. > --Safe to call under a non-sleepable lock or from an ithread > > Restrictions: > --Not guaranteed to be safe to call from an interrupt filter or under a spin > mutex on all platforms > --Current implementation does not guarantee more than one page of mapping > space across all platforms. MI code should not make nested calls to > pmap_quick_enter_page. > --MI code should not perform locking while holding onto a mapping created by > pmap_quick_enter_page > > The idea is to use this in busdma, for bounce buffer copies as well as > virtually-indexed cache maintenance on mips and arm. > > NOTE: the non-i386, non-amd64 implementations of these functions still need > review and testing.
Most of this description should go into a section 9 man page rather than the commit message ;-) /bz _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
