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[src/trunk]: src/sys/arch/alpha Move the pointer to the pmap's lev1map out of...



details:   https://anonhg.NetBSD.org/src/rev/860c37fa0d2f
branches:  trunk
changeset: 379370:860c37fa0d2f
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Sat May 29 23:27:22 2021 +0000

description:
Move the pointer to the pmap's lev1map out of the shared pmap structure
and into each CPU's pmap_percpu area.  This pointer is constant for the
life of the pmap, and moving it gives us an additional 8 bytes in the
shared pmap structure.

Because the kernel pmap does not have per-CPU data, all places where we
need the kernel pmap's lev1map now just reference kernel_lev1map directly.

diffstat:

 sys/arch/alpha/alpha/pmap.c       |  113 ++++++++++++++++++++++---------------
 sys/arch/alpha/alpha/vm_machdep.c |    6 +-
 sys/arch/alpha/include/pmap.h     |   45 ++++++++++-----
 3 files changed, 100 insertions(+), 64 deletions(-)

diffs (truncated from 464 to 300 lines):

diff -r a6817a44b21c -r 860c37fa0d2f sys/arch/alpha/alpha/pmap.c
--- a/sys/arch/alpha/alpha/pmap.c       Sat May 29 22:52:35 2021 +0000
+++ b/sys/arch/alpha/alpha/pmap.c       Sat May 29 23:27:22 2021 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.c,v 1.280 2021/05/29 22:14:09 thorpej Exp $ */
+/* $NetBSD: pmap.c,v 1.281 2021/05/29 23:27:22 thorpej Exp $ */
 
 /*-
  * Copyright (c) 1998, 1999, 2000, 2001, 2007, 2008, 2020
@@ -135,7 +135,7 @@
 
 #include <sys/cdefs.h>                 /* RCS ID & Copyright macro defns */
 
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.280 2021/05/29 22:14:09 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.281 2021/05/29 23:27:22 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -1173,19 +1173,19 @@ static bool     vtophys_internal(vaddr_t, pa
 ({                                                                     \
        pt_entry_t *l1pte_, *l2pte_;                                    \
                                                                        \
-       l1pte_ = pmap_l1pte(pmap_kernel(), va);                         \
+       l1pte_ = pmap_l1pte(kernel_lev1map, va);                        \
        if (pmap_pte_v(l1pte_) == 0) {                                  \
                printf("kernel level 1 PTE not valid, va 0x%lx "        \
                    "(line %d)\n", (va), __LINE__);                     \
                panic("PMAP_KERNEL_PTE");                               \
        }                                                               \
-       l2pte_ = pmap_l2pte(pmap_kernel(), va, l1pte_);                 \
+       l2pte_ = pmap_l2pte(kernel_lev1map, va, l1pte_);                \
        if (pmap_pte_v(l2pte_) == 0) {                                  \
                printf("kernel level 2 PTE not valid, va 0x%lx "        \
                    "(line %d)\n", (va), __LINE__);                     \
                panic("PMAP_KERNEL_PTE");                               \
        }                                                               \
-       pmap_l3pte(pmap_kernel(), va, l2pte_);                          \
+       pmap_l3pte(kernel_lev1map, va, l2pte_);                         \
 })
 #else
 #define        PMAP_KERNEL_PTE(va)     (&VPT[VPT_INDEX((va))])
@@ -1388,9 +1388,8 @@ pmap_bootstrap(paddr_t ptaddr, u_int max
         * generation.
         */
        memset(pmap_kernel(), 0, sizeof(struct pmap));
-       pmap_kernel()->pm_lev1map = kernel_lev1map;
        atomic_store_relaxed(&pmap_kernel()->pm_count, 1);
-       /* Kernel pmap does not have ASN info. */
+       /* Kernel pmap does not have per-CPU info. */
        TAILQ_INSERT_TAIL(&pmap_all_pmaps, pmap_kernel(), pm_list);
 
        /*
@@ -1562,6 +1561,7 @@ pmap_t
 pmap_create(void)
 {
        pmap_t pmap;
+       pt_entry_t *lev1map;
        int i;
 
 #ifdef DEBUG
@@ -1574,24 +1574,29 @@ pmap_create(void)
 
        atomic_store_relaxed(&pmap->pm_count, 1);
 
+ try_again:
+       rw_enter(&pmap_growkernel_lock, RW_READER);
+
+       lev1map = pool_cache_get(&pmap_l1pt_cache, PR_NOWAIT);
+       if (__predict_false(lev1map == NULL)) {
+               rw_exit(&pmap_growkernel_lock);
+               (void) kpause("pmap_create", false, hz >> 2, NULL);
+               goto try_again;
+       }
+
        /*
         * There are only kernel mappings at this point; give the pmap
         * the kernel ASN.  This will be initialized to correct values
         * when the pmap is activated.
+        *
+        * We stash a pointer to the pmap's lev1map in each CPU's
+        * private data.  It remains constant for the life of the
+        * pmap, and gives us more room in the shared pmap structure.
         */
        for (i = 0; i < pmap_ncpuids; i++) {
                pmap->pm_percpu[i].pmc_asn = PMAP_ASN_KERNEL;
                pmap->pm_percpu[i].pmc_asngen = PMAP_ASNGEN_INVALID;
-       }
-
- try_again:
-       rw_enter(&pmap_growkernel_lock, RW_READER);
-
-       pmap->pm_lev1map = pool_cache_get(&pmap_l1pt_cache, PR_NOWAIT);
-       if (__predict_false(pmap->pm_lev1map == NULL)) {
-               rw_exit(&pmap_growkernel_lock);
-               (void) kpause("pmap_create", false, hz >> 2, NULL);
-               goto try_again;
+               pmap->pm_percpu[i].pmc_lev1map = lev1map;
        }
 
        mutex_enter(&pmap_all_pmaps_lock);
@@ -1623,6 +1628,9 @@ pmap_destroy(pmap_t pmap)
        if (atomic_dec_uint_nv(&pmap->pm_count) > 0)
                return;
 
+       pt_entry_t *lev1map = pmap_lev1map(pmap);
+       int i;
+
        rw_enter(&pmap_growkernel_lock, RW_READER);
 
        /*
@@ -1632,8 +1640,12 @@ pmap_destroy(pmap_t pmap)
        TAILQ_REMOVE(&pmap_all_pmaps, pmap, pm_list);
        mutex_exit(&pmap_all_pmaps_lock);
 
-       pool_cache_put(&pmap_l1pt_cache, pmap->pm_lev1map);
-       pmap->pm_lev1map = (pt_entry_t *)0xdeadbeefUL;
+       pool_cache_put(&pmap_l1pt_cache, lev1map);
+#ifdef DIAGNOSTIC
+       for (i = 0; i < pmap_ncpuids; i++) {
+               pmap->pm_percpu[i].pmc_lev1map = (pt_entry_t *)0xdeadbeefUL;
+       }
+#endif /* DIAGNOSTIC */
 
        rw_exit(&pmap_growkernel_lock);
 
@@ -1714,19 +1726,21 @@ pmap_remove_internal(pmap_t pmap, vaddr_
                return;
        }
 
+       pt_entry_t * const lev1map = pmap_lev1map(pmap);
+
        KASSERT(sva < VM_MAXUSER_ADDRESS);
        KASSERT(eva <= VM_MAXUSER_ADDRESS);
-       KASSERT(pmap->pm_lev1map != kernel_lev1map);
+       KASSERT(lev1map != kernel_lev1map);
 
        PMAP_MAP_TO_HEAD_LOCK();
        PMAP_LOCK(pmap);
 
-       l1pte = pmap_l1pte(pmap, sva);
+       l1pte = pmap_l1pte(lev1map, sva);
 
        for (; sva < eva; sva = l1eva, l1pte++) {
                l1eva = alpha_trunc_l1seg(sva) + ALPHA_L1SEG_SIZE;
                if (pmap_pte_v(l1pte)) {
-                       saved_l2pte = l2pte = pmap_l2pte(pmap, sva, l1pte);
+                       saved_l2pte = l2pte = pmap_l2pte(lev1map, sva, l1pte);
 
                        /*
                         * Add a reference to the L2 table so it won't
@@ -1739,7 +1753,7 @@ pmap_remove_internal(pmap_t pmap, vaddr_
                                    alpha_trunc_l2seg(sva) + ALPHA_L2SEG_SIZE;
                                if (pmap_pte_v(l2pte)) {
                                        saved_l3pte = l3pte =
-                                           pmap_l3pte(pmap, sva, l2pte);
+                                           pmap_l3pte(lev1map, sva, l2pte);
 
                                        /*
                                         * Add a reference to the L3 table so
@@ -1913,19 +1927,20 @@ pmap_protect(pmap_t pmap, vaddr_t sva, v
        }
 
        const pt_entry_t bits = pte_prot(pmap, prot);
+       pt_entry_t * const lev1map = pmap_lev1map(pmap);
 
        PMAP_LOCK(pmap);
 
-       l1pte = pmap_l1pte(pmap, sva);
+       l1pte = pmap_l1pte(lev1map, sva);
        for (; sva < eva; sva = l1eva, l1pte++) {
                l1eva = alpha_trunc_l1seg(sva) + ALPHA_L1SEG_SIZE;
                if (pmap_pte_v(l1pte)) {
-                       l2pte = pmap_l2pte(pmap, sva, l1pte);
+                       l2pte = pmap_l2pte(lev1map, sva, l1pte);
                        for (; sva < l1eva && sva < eva; sva = l2eva, l2pte++) {
                                l2eva =
                                    alpha_trunc_l2seg(sva) + ALPHA_L2SEG_SIZE;
                                if (pmap_pte_v(l2pte)) {
-                                       l3pte = pmap_l3pte(pmap, sva, l2pte);
+                                       l3pte = pmap_l3pte(lev1map, sva, l2pte);
                                        for (; sva < l2eva && sva < eva;
                                             sva += PAGE_SIZE, l3pte++) {
                                                if (pmap_pte_v(l3pte) &&
@@ -2065,9 +2080,10 @@ pmap_enter(pmap_t pmap, vaddr_t va, padd
                pte = PMAP_KERNEL_PTE(va);
        } else {
                pt_entry_t *l1pte, *l2pte;
+               pt_entry_t * const lev1map = pmap_lev1map(pmap);
 
                KASSERT(va < VM_MAXUSER_ADDRESS);
-               KASSERT(pmap->pm_lev1map != kernel_lev1map);
+               KASSERT(lev1map != kernel_lev1map);
 
                /*
                 * Check to see if the level 1 PTE is valid, and
@@ -2075,7 +2091,7 @@ pmap_enter(pmap_t pmap, vaddr_t va, padd
                 * A reference will be added to the level 2 table when
                 * the level 3 table is created.
                 */
-               l1pte = pmap_l1pte(pmap, va);
+               l1pte = pmap_l1pte(lev1map, va);
                if (pmap_pte_v(l1pte) == 0) {
                        pmap_physpage_addref(l1pte);
                        error = pmap_ptpage_alloc(l1pte, PGU_L2PT);
@@ -2099,7 +2115,7 @@ pmap_enter(pmap_t pmap, vaddr_t va, padd
                 * A reference will be added to the level 3 table when
                 * the mapping is validated.
                 */
-               l2pte = pmap_l2pte(pmap, va, l1pte);
+               l2pte = pmap_l2pte(lev1map, va, l1pte);
                if (pmap_pte_v(l2pte) == 0) {
                        pmap_physpage_addref(l2pte);
                        error = pmap_ptpage_alloc(l2pte, PGU_L3PT);
@@ -2123,7 +2139,7 @@ pmap_enter(pmap_t pmap, vaddr_t va, padd
                /*
                 * Get the PTE that will map the page.
                 */
-               pte = pmap_l3pte(pmap, va, l2pte);
+               pte = pmap_l3pte(lev1map, va, l2pte);
        }
 
        /* Remember all of the old PTE; used for TBI check later. */
@@ -2409,7 +2425,7 @@ pmap_unwire(pmap_t pmap, vaddr_t va)
 
        PMAP_LOCK(pmap);
 
-       pte = pmap_l3pte(pmap, va, NULL);
+       pte = pmap_l3pte(pmap_lev1map(pmap), va, NULL);
 
        KASSERT(pte != NULL);
        KASSERT(pmap_pte_v(pte));
@@ -2469,17 +2485,19 @@ pmap_extract(pmap_t pmap, vaddr_t va, pa
                return false;
        }
 
+       pt_entry_t * const lev1map = pmap_lev1map(pmap);
+
        PMAP_LOCK(pmap);
 
-       l1pte = pmap_l1pte(pmap, va);
+       l1pte = pmap_l1pte(lev1map, va);
        if (pmap_pte_v(l1pte) == 0)
                goto out;
 
-       l2pte = pmap_l2pte(pmap, va, l1pte);
+       l2pte = pmap_l2pte(lev1map, va, l1pte);
        if (pmap_pte_v(l2pte) == 0)
                goto out;
 
-       l3pte = pmap_l3pte(pmap, va, l2pte);
+       l3pte = pmap_l3pte(lev1map, va, l2pte);
        if (pmap_pte_v(l3pte) == 0)
                goto out;
 
@@ -2562,7 +2580,7 @@ pmap_activate(struct lwp *l)
                pcb->pcb_hw.apcb_asn = PMAP_ASN_KERNEL;
        }
        pcb->pcb_hw.apcb_ptbr =
-           ALPHA_K0SEG_TO_PHYS((vaddr_t)pmap->pm_lev1map) >> PGSHIFT;
+           ALPHA_K0SEG_TO_PHYS((vaddr_t)pmap_lev1map(pmap)) >> PGSHIFT;
 
        /*
         * Check to see if the ASN or page table base has changed; if
@@ -2926,7 +2944,7 @@ pmap_remove_mapping(pmap_t pmap, vaddr_t
         * PTE not provided, compute it from pmap and va.
         */
        if (pte == NULL) {
-               pte = pmap_l3pte(pmap, va, NULL);
+               pte = pmap_l3pte(pmap_lev1map(pmap), va, NULL);
                if (pmap_pte_v(pte) == 0)
                        return 0;
        }
@@ -3063,7 +3081,7 @@ pmap_emulate_reference(struct lwp *l, va
 #endif
                PMAP_LOCK(pmap);
                didlock = true;
-               pte = pmap_l3pte(pmap, v, NULL);
+               pte = pmap_l3pte(pmap_lev1map(pmap), v, NULL);
                /*
                 * We'll unlock below where we're done with the PTE.
                 */
@@ -3468,9 +3486,10 @@ pmap_kptpage_alloc(paddr_t *pap)
 vaddr_t
 pmap_growkernel(vaddr_t maxkvaddr)
 {
-       struct pmap *kpm = pmap_kernel(), *pm;
+       struct pmap *pm;
        paddr_t ptaddr;
        pt_entry_t *l1pte, *l2pte, pte;
+       pt_entry_t *lev1map;
        vaddr_t va;
        int l1idx;
 
@@ -3487,7 +3506,7 @@ pmap_growkernel(vaddr_t maxkvaddr)
                 * allocate a new L2 PT page and insert it into the
                 * L1 map.
                 */
-               l1pte = pmap_l1pte(kpm, va);
+               l1pte = pmap_l1pte(kernel_lev1map, va);
                if (pmap_pte_v(l1pte) == 0) {



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