On Tuesday, July 15, 2014 9:52:20 am Ian Lepore wrote: > On Tue, 2014-07-15 at 09:30 +0000, Konstantin Belousov wrote: > > Author: kib > > Date: Tue Jul 15 09:30:43 2014 > > New Revision: 268660 > > URL: http://svnweb.freebsd.org/changeset/base/268660 > > > > Log: > > Make amd64 pmap_copy_pages() functional for pages not mapped by DMAP. > > > > Requested and reviewed by: royger > > Tested by: pho, royger > > Sponsored by: The FreeBSD Foundation > > MFC after: 1 week > > > > Modified: > > head/sys/amd64/amd64/pmap.c > > > > Modified: head/sys/amd64/amd64/pmap.c > > ============================================================================== > > --- head/sys/amd64/amd64/pmap.c Tue Jul 15 05:45:50 2014 > > (r268659) > > +++ head/sys/amd64/amd64/pmap.c Tue Jul 15 09:30:43 2014 > > (r268660) > > @@ -390,6 +390,11 @@ SYSCTL_PROC(_vm_pmap, OID_AUTO, pcid_sav > > CTLFLAG_MPSAFE, NULL, 0, pmap_pcid_save_cnt_proc, "QU", > > "Count of saved TLB context on switch"); > > > > +/* pmap_copy_pages() over non-DMAP */ > > +static struct mtx cpage_lock; > > +static vm_offset_t cpage_a; > > +static vm_offset_t cpage_b; > > + > > /* > > * Crashdump maps. > > */ > > @@ -1055,6 +1060,10 @@ pmap_init(void) > > M_WAITOK | M_ZERO); > > for (i = 0; i < pv_npg; i++) > > TAILQ_INIT(&pv_table[i].pv_list); > > + > > + mtx_init(&cpage_lock, "cpage", NULL, MTX_DEF); > > + cpage_a = kva_alloc(PAGE_SIZE); > > + cpage_b = kva_alloc(PAGE_SIZE); > > } > > > > static SYSCTL_NODE(_vm_pmap, OID_AUTO, pde, CTLFLAG_RD, 0, > > @@ -5064,19 +5073,58 @@ pmap_copy_pages(vm_page_t ma[], vm_offse > > vm_offset_t b_offset, int xfersize) > > { > > void *a_cp, *b_cp; > > + vm_page_t m_a, m_b; > > + vm_paddr_t p_a, p_b; > > + pt_entry_t *pte; > > vm_offset_t a_pg_offset, b_pg_offset; > > int cnt; > > + boolean_t pinned; > > > > + pinned = FALSE; > > while (xfersize > 0) { > > a_pg_offset = a_offset & PAGE_MASK; > > - cnt = min(xfersize, PAGE_SIZE - a_pg_offset); > > - a_cp = (char *)PHYS_TO_DMAP(ma[a_offset >> PAGE_SHIFT]-> > > - phys_addr) + a_pg_offset; > > + m_a = ma[a_offset >> PAGE_SHIFT]; > > + p_a = m_a->phys_addr; > > b_pg_offset = b_offset & PAGE_MASK; > > + m_b = mb[b_offset >> PAGE_SHIFT]; > > + p_b = m_b->phys_addr; > > + cnt = min(xfersize, PAGE_SIZE - a_pg_offset); > > cnt = min(cnt, PAGE_SIZE - b_pg_offset); > > - b_cp = (char *)PHYS_TO_DMAP(mb[b_offset >> PAGE_SHIFT]-> > > - phys_addr) + b_pg_offset; > > + if (__predict_false(p_a < DMAP_MIN_ADDRESS || > > + p_a > DMAP_MIN_ADDRESS + dmaplimit)) { > > + mtx_lock(&cpage_lock); > > + sched_pin(); > > + pinned = TRUE; > > + pte = vtopte(cpage_a); > > + *pte = p_a | X86_PG_A | X86_PG_V | > > + pmap_cache_bits(kernel_pmap, m_a->md.pat_mode, 0); > > + invlpg(cpage_a); > > + a_cp = (char *)cpage_a + a_pg_offset; > > + } else { > > + a_cp = (char *)PHYS_TO_DMAP(p_a) + a_pg_offset; > > + } > > + if (__predict_false(p_b < DMAP_MIN_ADDRESS || > > + p_b > DMAP_MIN_ADDRESS + dmaplimit)) { > > + if (!pinned) { > > + mtx_lock(&cpage_lock); > > + sched_pin(); > > + pinned = TRUE; > > + } > > + pte = vtopte(cpage_b); > > + *pte = p_b | X86_PG_A | X86_PG_M | X86_PG_RW | > > + X86_PG_V | pmap_cache_bits(kernel_pmap, > > + m_b->md.pat_mode, 0); > > + invlpg(cpage_b); > > + b_cp = (char *)cpage_b + b_pg_offset; > > + } else { > > + b_cp = (char *)PHYS_TO_DMAP(p_b) + b_pg_offset; > > + } > > bcopy(a_cp, b_cp, cnt); > > + if (__predict_false(pinned)) { > > + sched_unpin(); > > + mtx_unlock(&cpage_lock); > > + pinned = FALSE; > > Should this pinned = FALSE be done under the cpage_lock to avoid a race?
It's a local variable, how would it race? (No other thread/CPU should be able to "get" to it to either read or write to it, only curthread, so it shouldn't need any locking.) -- John Baldwin _______________________________________________ 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"
