Date: Thu, 29 Aug 2013 12:41:32 -0500 From: Alan Cox <alc@rice.edu> To: mips@freebsd.org Cc: Alan Cox <alc@rice.edu> Subject: pmap patch Message-ID: <521F87CC.9050205@rice.edu>
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Can folks here please test the attached patch against HEAD? This patch
implements the new pmap_advise() function for MIPS.
Alan
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Index: mips/mips/pmap.c
===================================================================
--- mips/mips/pmap.c (revision 255028)
+++ mips/mips/pmap.c (working copy)
@@ -2919,6 +2919,85 @@ pmap_is_prefaultable(pmap_t pmap, vm_offset_t addr
void
pmap_advise(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, int advice)
{
+ pd_entry_t *pde, *pdpe;
+ pt_entry_t *pte;
+ vm_offset_t va, va_next;
+ vm_paddr_t pa;
+ vm_page_t m;
+
+ if (advice != MADV_DONTNEED && advice != MADV_FREE)
+ return;
+ rw_wlock(&pvh_global_lock);
+ PMAP_LOCK(pmap);
+ for (; sva < eva; sva = va_next) {
+ pdpe = pmap_segmap(pmap, sva);
+#ifdef __mips_n64
+ if (*pdpe == 0) {
+ va_next = (sva + NBSEG) & ~SEGMASK;
+ if (va_next < sva)
+ va_next = eva;
+ continue;
+ }
+#endif
+ va_next = (sva + NBPDR) & ~PDRMASK;
+ if (va_next < sva)
+ va_next = eva;
+
+ pde = pmap_pdpe_to_pde(pdpe, sva);
+ if (*pde == NULL)
+ continue;
+
+ /*
+ * Limit our scan to either the end of the va represented
+ * by the current page table page, or to the end of the
+ * range being write protected.
+ */
+ if (va_next > eva)
+ va_next = eva;
+
+ va = va_next;
+ for (pte = pmap_pde_to_pte(pde, sva); sva != va_next; pte++,
+ sva += PAGE_SIZE) {
+ if (!pte_test(pte, PTE_MANAGED | PTE_V)) {
+ if (va != va_next) {
+ pmap_invalidate_range(pmap, va, sva);
+ va = va_next;
+ }
+ continue;
+ }
+ pa = TLBLO_PTE_TO_PA(*pte);
+ m = PHYS_TO_VM_PAGE(pa);
+ m->md.pv_flags &= ~PV_TABLE_REF;
+ if (pte_test(pte, PTE_D)) {
+ if (advice == MADV_DONTNEED) {
+ /*
+ * Future calls to pmap_is_modified()
+ * can be avoided by making the page
+ * dirty now.
+ */
+ vm_page_dirty(m);
+ } else {
+ pte_clear(pte, PTE_D);
+ if (va == va_next)
+ va = sva;
+ }
+ } else {
+ /*
+ * Unless PTE_D is set, any TLB entries
+ * mapping "sva" don't allow write access, so
+ * they needn't be invalidated.
+ */
+ if (va != va_next) {
+ pmap_invalidate_range(pmap, va, sva);
+ va = va_next;
+ }
+ }
+ }
+ if (va != va_next)
+ pmap_invalidate_range(pmap, va, sva);
+ }
+ rw_wunlock(&pvh_global_lock);
+ PMAP_UNLOCK(pmap);
}
/*
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