On Sat, Dec 28, 2013 at 06:49:25PM -0600, Alan Cox wrote: > On 12/28/2013 18:02, Nathan Whitehorn wrote: > > On 12/26/13 00:46, Marcel Moolenaar wrote: > >> Author: marcel > >> Date: Thu Dec 26 05:46:10 2013 > >> New Revision: 259908 > >> URL: http://svnweb.freebsd.org/changeset/base/259908 > >> > >> Log: > >> For ia64, use pmap_remove_pages() and not pmap_remove(). The problem is > >> that we don't have a good way (yet) to iterate over the mapped pages by > >> virtual address and simply try each page within the range. Given that we > >> call pmap_remove() over the entire 2^63 bytes of address space, it takes > >> a while for pmap_remove to have tried all 2^50 pages. > >> By using pmap_remove_pages() we use the PV list to find all mappings. > >> > >> Change derived from a patch by: alc > >> > > Why make this ia64-specific? It seems like a potentially useful general > > optimization and certainly shouldn't be harmful on other architectures. > > Some of the other implementations of pmap_remove_pages() have > limitations that don't permit them to be used for this purpose, e.g., > > if (pmap != PCPU_GET(curpmap)) { > printf("warning: pmap_remove_pages called with > non-current pmap\n"); > return; > }
BTW, I do not easily see why the current amd64 implementation needs the pmap being current. I do not see accesses to recursive page table mappings in the code.
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