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author | alc <alc@FreeBSD.org> | 2005-09-04 19:06:27 +0000 |
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committer | alc <alc@FreeBSD.org> | 2005-09-04 19:06:27 +0000 |
commit | 9a159e7bd9578d2bf32cffd83221962b966d1857 (patch) | |
tree | ee4bb90320bb3a21efcb8bb76617dedf50046837 /sys/amd64 | |
parent | ea45d0596e491d812d39e558dacfc53c6833b585 (diff) | |
download | FreeBSD-src-9a159e7bd9578d2bf32cffd83221962b966d1857.zip FreeBSD-src-9a159e7bd9578d2bf32cffd83221962b966d1857.tar.gz |
Eliminate unnecessary TLB invalidations by pmap_enter(). Specifically,
eliminate TLB invalidations when permissions are relaxed, such as when a
read-only mapping is changed to a read/write mapping. Additionally,
eliminate TLB invalidations when bits that are ignored by the hardware,
such as PG_W ("wired mapping"), are changed.
Reviewed by: tegge
Diffstat (limited to 'sys/amd64')
-rw-r--r-- | sys/amd64/amd64/pmap.c | 38 |
1 files changed, 22 insertions, 16 deletions
diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c index 17c9e64..4c188aa 100644 --- a/sys/amd64/amd64/pmap.c +++ b/sys/amd64/amd64/pmap.c @@ -1872,6 +1872,7 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot, vm_paddr_t opa; pt_entry_t origpte, newpte; vm_page_t mpte, om; + boolean_t invlva; va = trunc_page(va); #ifdef PMAP_DIAGNOSTIC @@ -1935,14 +1936,6 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot, else if (!wired && (origpte & PG_W)) pmap->pm_stats.wired_count--; -#if defined(PMAP_DIAGNOSTIC) - if (pmap_nw_modified((pt_entry_t) origpte)) { - printf( - "pmap_enter: modified page not writable: va: 0x%lx, pte: 0x%lx\n", - va, origpte); - } -#endif - /* * Remove extra pte reference */ @@ -2014,17 +2007,30 @@ validate: * to update the pte. */ if ((origpte & ~(PG_M|PG_A)) != newpte) { - if (origpte & PG_MANAGED) { + if (origpte & PG_V) { + invlva = FALSE; origpte = pte_load_store(pte, newpte | PG_A); - if ((origpte & PG_M) && pmap_track_modified(va)) - vm_page_dirty(om); - if (origpte & PG_A) - vm_page_flag_set(om, PG_REFERENCED); + if (origpte & PG_A) { + if (origpte & PG_MANAGED) + vm_page_flag_set(om, PG_REFERENCED); + if (opa != VM_PAGE_TO_PHYS(m) || ((origpte & + PG_NX) == 0 && (newpte & PG_NX))) + invlva = TRUE; + } + if (origpte & PG_M) { + KASSERT((origpte & PG_RW), + ("pmap_enter: modified page not writable:" + " va: 0x%lx, pte: 0x%lx", va, origpte)); + if ((origpte & PG_MANAGED) && + pmap_track_modified(va)) + vm_page_dirty(om); + if ((newpte & PG_RW) == 0) + invlva = TRUE; + } + if (invlva) + pmap_invalidate_page(pmap, va); } else pte_store(pte, newpte | PG_A); - if (origpte) { - pmap_invalidate_page(pmap, va); - } } vm_page_unlock_queues(); PMAP_UNLOCK(pmap); |