Date: Sun, 5 Aug 2012 16:59:02 +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: r239072 - head/sys/amd64/amd64 Message-ID: <201208051659.q75Gx26M004986@svn.freebsd.org>
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Author: alc Date: Sun Aug 5 16:59:02 2012 New Revision: 239072 URL: http://svn.freebsd.org/changeset/base/239072 Log: Shave off a few more cycles from the average execution time of pmap_enter() by simplifying the control flow and reducing the live range of "om". Modified: head/sys/amd64/amd64/pmap.c Modified: head/sys/amd64/amd64/pmap.c ============================================================================== --- head/sys/amd64/amd64/pmap.c Sun Aug 5 15:55:36 2012 (r239071) +++ head/sys/amd64/amd64/pmap.c Sun Aug 5 16:59:02 2012 (r239072) @@ -3468,7 +3468,7 @@ pmap_enter(pmap_t pmap, vm_offset_t va, newpte |= PG_G; newpte |= pmap_cache_bits(m->md.pat_mode, 0); - mpte = om = NULL; + mpte = NULL; lock = NULL; rw_rlock(&pvh_global_lock); @@ -3540,12 +3540,6 @@ retry: if (((origpte ^ newpte) & ~(PG_M | PG_A)) == 0) goto unchanged; goto validate; - } else { - /* - * Yes, fall through to validate the new mapping. - */ - if ((origpte & PG_MANAGED) != 0) - om = PHYS_TO_VM_PAGE(opa); } } else { /* @@ -3578,6 +3572,7 @@ validate: opa = origpte & PG_FRAME; if (opa != pa) { if ((origpte & PG_MANAGED) != 0) { + om = PHYS_TO_VM_PAGE(opa); if ((origpte & (PG_M | PG_RW)) == (PG_M | PG_RW)) vm_page_dirty(om);
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