Date: Sun, 15 Dec 2019 22:41:58 +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: r355787 - head/sys/arm64/arm64 Message-ID: <201912152241.xBFMfwZE083181@repo.freebsd.org>
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Author: alc Date: Sun Dec 15 22:41:57 2019 New Revision: 355787 URL: https://svnweb.freebsd.org/changeset/base/355787 Log: Apply a small optimization to pmap_remove_l3_range(). Specifically, hoist a PHYS_TO_VM_PAGE() operation that always returns the same vm_page_t out of the loop. (Since arm64 is configured as VM_PHYSSEG_SPARSE, the implementation of PHYS_TO_VM_PAGE() is more costly than that of VM_PHYSSEG_DENSE platforms, like amd64.) MFC after: 1 week Modified: head/sys/arm64/arm64/pmap.c Modified: head/sys/arm64/arm64/pmap.c ============================================================================== --- head/sys/arm64/arm64/pmap.c Sun Dec 15 21:52:40 2019 (r355786) +++ head/sys/arm64/arm64/pmap.c Sun Dec 15 22:41:57 2019 (r355787) @@ -2616,11 +2616,13 @@ pmap_remove_l3_range(pmap_t pmap, pd_entry_t l2e, vm_o struct rwlock *new_lock; pt_entry_t *l3, old_l3; vm_offset_t va; - vm_page_t m; + vm_page_t l3pg, m; PMAP_LOCK_ASSERT(pmap, MA_OWNED); KASSERT(rounddown2(sva, L2_SIZE) + L2_SIZE == roundup2(eva, L2_SIZE), ("pmap_remove_l3_range: range crosses an L3 page table boundary")); + l3pg = sva < VM_MAXUSER_ADDRESS ? PHYS_TO_VM_PAGE(l2e & ~ATTR_MASK) : + NULL; va = eva; for (l3 = pmap_l2_to_l3(&l2e, sva); sva != eva; l3++, sva += L3_SIZE) { if (!pmap_l3_valid(pmap_load(l3))) { @@ -2671,7 +2673,7 @@ pmap_remove_l3_range(pmap_t pmap, pd_entry_t l2e, vm_o } if (va == eva) va = sva; - if (pmap_unuse_pt(pmap, sva, l2e, free)) { + if (l3pg != NULL && pmap_unwire_l3(pmap, sva, l3pg, free)) { sva += L3_SIZE; break; }
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