Date: Sat, 29 Sep 2012 17:20:17 +0000 (UTC) From: Alan Cox <alc@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r241054 - head/sys/arm/arm Message-ID: <201209291720.q8THKHbq063058@svn.freebsd.org>
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Author: alc Date: Sat Sep 29 17:20:16 2012 New Revision: 241054 URL: http://svn.freebsd.org/changeset/base/241054 Log: Add support for mincore(). Specifically, this is an adaptation of the pmap_mincore() implementation that was added to the original arm pmap in r235717. Modified: head/sys/arm/arm/pmap-v6.c Modified: head/sys/arm/arm/pmap-v6.c ============================================================================== --- head/sys/arm/arm/pmap-v6.c Sat Sep 29 16:47:56 2012 (r241053) +++ head/sys/arm/arm/pmap-v6.c Sat Sep 29 17:20:16 2012 (r241054) @@ -3462,9 +3462,59 @@ pmap_remove_write(vm_page_t m) int pmap_mincore(pmap_t pmap, vm_offset_t addr, vm_paddr_t *locked_pa) { - printf("pmap_mincore()\n"); - - return (0); + struct l2_bucket *l2b; + pt_entry_t *ptep, pte; + vm_paddr_t pa; + vm_page_t m; + int val; + boolean_t managed; + + PMAP_LOCK(pmap); +retry: + l2b = pmap_get_l2_bucket(pmap, addr); + if (l2b == NULL) { + val = 0; + goto out; + } + ptep = &l2b->l2b_kva[l2pte_index(addr)]; + pte = *ptep; + if (!l2pte_valid(pte)) { + val = 0; + goto out; + } + val = MINCORE_INCORE; + if (L2_S_WRITABLE(pte)) + val |= MINCORE_MODIFIED | MINCORE_MODIFIED_OTHER; + managed = FALSE; + pa = l2pte_pa(pte); + m = PHYS_TO_VM_PAGE(pa); + if (m != NULL && (m->oflags & VPO_UNMANAGED) == 0) + managed = TRUE; + if (managed) { + /* + * The ARM pmap tries to maintain a per-mapping + * reference bit. The trouble is that it's kept in + * the PV entry, not the PTE, so it's costly to access + * here. You would need to acquire the pvh global + * lock, call pmap_find_pv(), and introduce a custom + * version of vm_page_pa_tryrelock() that releases and + * reacquires the pvh global lock. In the end, I + * doubt it's worthwhile. This may falsely report + * the given address as referenced. + */ + if ((m->md.pvh_attrs & PVF_REF) != 0) + val |= MINCORE_REFERENCED | MINCORE_REFERENCED_OTHER; + } + if ((val & (MINCORE_MODIFIED_OTHER | MINCORE_REFERENCED_OTHER)) != + (MINCORE_MODIFIED_OTHER | MINCORE_REFERENCED_OTHER) && managed) { + /* Ensure that "PHYS_TO_VM_PAGE(pa)->object" doesn't change. */ + if (vm_page_pa_tryrelock(pmap, pa, locked_pa)) + goto retry; + } else +out: + PA_UNLOCK_COND(*locked_pa); + PMAP_UNLOCK(pmap); + return (val); } void
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