Implement code to dynamically size the number of page tables based on available
RAM at boot. Also did some cleanup of unused functions, updated several comments, and removed unecessary 'XXX's.
This commit is contained in:
jeremy
parent
7c77aacfb1
commit
0304ff6aed
@ -1,4 +1,4 @@
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/* $NetBSD: pmap.c,v 1.21 1997/05/01 15:00:11 gwr Exp $ */
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/* $NetBSD: pmap.c,v 1.22 1997/05/20 06:01:19 jeremy Exp $ */
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/*-
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* Copyright (c) 1996, 1997 The NetBSD Foundation, Inc.
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@ -331,9 +331,13 @@ u_int total_phys_mem;
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* currently _runnable_ processes. (Sleeping ones don't count.)
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* The amount of physical memory should be irrelevant. -gwr
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*/
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#ifdef FIXED_NTABLES
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#define NUM_A_TABLES 16
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#define NUM_B_TABLES 32
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#define NUM_C_TABLES 64
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#else
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unsigned int NUM_A_TABLES, NUM_B_TABLES, NUM_C_TABLES;
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#endif /* FIXED_NTABLES */
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/*
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* This determines our total virtual mapping capacity.
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@ -728,6 +732,20 @@ pmap_bootstrap(nextva)
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* Allocate user MMU tables.
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* These must be contiguous with the preceeding.
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*/
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#ifndef FIXED_NTABLES
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/*
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* The number of user-level C tables that should be allocated is
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* related to the size of physical memory. In general, there should
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* be enough tables to map four times the amount of available RAM.
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* The extra amount is needed because some table space is wasted by
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* fragmentation.
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*/
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NUM_C_TABLES = (total_phys_mem * 4) / (MMU_C_TBL_SIZE * MMU_PAGE_SIZE);
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NUM_B_TABLES = NUM_C_TABLES / 2;
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NUM_A_TABLES = NUM_B_TABLES / 2;
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#endif /* !FIXED_NTABLES */
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size = sizeof(mmu_short_pte_t) * MMU_C_TBL_SIZE * NUM_C_TABLES;
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mmuCbase = pmap_bootstrap_alloc(size);
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@ -1368,7 +1386,7 @@ free_a_table(a_tbl, relink)
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/*
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* Flush the ATC cache of all cached descriptors derived
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* from this table.
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* XXX - Sun3x does not use 68851's cached table feature
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* Sun3x does not use 68851's cached table feature
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* flush_atc_crp(mmu_vtop(a_tbl->dte));
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*/
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@ -1376,7 +1394,7 @@ free_a_table(a_tbl, relink)
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* Remove any pending cache flushes that were designated
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* for the pmap this A table belongs to.
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* a_tbl->parent->atc_flushq[0] = 0;
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* XXX - Not implemented in sun3x.
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* Not implemented in sun3x.
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*/
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/*
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@ -1600,53 +1618,6 @@ pmap_remove_pte(pte)
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pte->attr.raw = MMU_DT_INVALID;
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}
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#if 0 /* XXX - I am eliminating this function. -j */
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/* pmap_dereference_pte INTERNAL
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**
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* Update the necessary reference counts in any tables and pmaps to
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* reflect the removal of the given pte. Only called when no knowledge of
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* the pte's associated pmap is unknown. This only occurs in the PV call
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* 'pmap_page_protect()' with a protection of VM_PROT_NONE, which means
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* that all references to a given physical page must be removed.
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*/
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void
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pmap_dereference_pte(pte)
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mmu_short_pte_t *pte;
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{
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vm_offset_t va;
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c_tmgr_t *c_tbl;
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pmap_t pmap;
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va = pmap_get_pteinfo(pte, &pmap, &c_tbl);
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/*
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* Flush the translation cache of the page mapped by the PTE, should
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* it prove to be in the current pmap. Kernel mappings appear in
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* all address spaces, so they always should be flushed
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*/
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if (pmap == pmap_kernel() || pmap == current_pmap())
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TBIS(va);
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/*
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* If the mapping belongs to a user map, update the necessary
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* reference counts in the table manager. XXX - It would be
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* much easier to keep the resident count in the c_tmgr_t -gwr
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*/
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if (pmap != pmap_kernel()) {
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/*
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* Most of the situations in which pmap_dereference_pte() is
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* called are usually temporary removals of a mapping. Often
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* the mapping is reinserted shortly afterwards. If the parent
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* C table's valid entry count reaches zero as a result of
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* removing this mapping, we could return it to the free pool,
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* but we leave it alone because it is likely to be used as
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* stated above.
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*/
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c_tbl->ct_ecnt--;
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pmap->pm_stats.resident_count--;
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}
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}
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#endif 0 /* function elimination */
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/* pmap_stroll INTERNAL
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**
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* Retrieve the addresses of all table managers involved in the mapping of
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@ -1744,9 +1715,9 @@ pmap_enter(pmap, va, pa, prot, wired)
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pa &= MMU_PAGE_MASK;
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/*
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* Determine if the physical address being mapped is managed.
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* If it isn't, the mapping should be cache inhibited. (This is
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* applied later in the function.) XXX - Why non-cached? -gwr
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* Determine if the physical address being mapped is on-board RAM.
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* Any other area of the address space is likely to belong to a
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* device and hence it would be disasterous to cache its contents.
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*/
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if ((managed = is_managed(pa)) == FALSE)
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flags |= PMAP_NC;
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@ -2102,7 +2073,7 @@ pmap_enter_kernel(va, pa, prot)
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*/
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pte_idx = (u_long) _btop(va - KERNBASE);
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/* XXX - This array is traditionally named "Sysmap" */
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/* This array is traditionally named "Sysmap" */
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pte = &kernCbase[pte_idx];
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s = splimp();
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@ -2594,14 +2565,6 @@ pmap_release(pmap)
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* which always should be the case whenever
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* this function is called, there really should
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* be nothing to do.
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*
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* XXX - This function is being called while there are
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* still valid mappings, so I guess the above must not
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* be true.
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* XXX - Unless the mappings persist due to a bug here...
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* + That's what was happening. The map had no mappings,
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* but it still had an A table. pmap_remove() was not
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* releasing tables when they were empty.
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*/
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#ifdef PMAP_DEBUG
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if (pmap == NULL)
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@ -2917,21 +2880,6 @@ pmap_get_pteinfo(idx, pmap, tbl)
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return va;
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}
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#if 0 /* XXX - I am eliminating this function. */
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/* pmap_find_tic INTERNAL
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**
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* Given the address of a pte, find the TIC (level 'C' table index) for
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* the pte within its C table.
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*/
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char
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pmap_find_tic(pte)
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mmu_short_pte_t *pte;
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{
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return ((pte - mmuCbase) % MMU_C_TBL_SIZE);
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}
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#endif /* 0 */
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/* pmap_clear_modify INTERFACE
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**
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* Clear the modification bit on the page at the specified
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@ -1,4 +1,4 @@
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/* $NetBSD: pmap.c,v 1.21 1997/05/01 15:00:11 gwr Exp $ */
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/* $NetBSD: pmap.c,v 1.22 1997/05/20 06:01:19 jeremy Exp $ */
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/*-
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* Copyright (c) 1996, 1997 The NetBSD Foundation, Inc.
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@ -331,9 +331,13 @@ u_int total_phys_mem;
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* currently _runnable_ processes. (Sleeping ones don't count.)
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* The amount of physical memory should be irrelevant. -gwr
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*/
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#ifdef FIXED_NTABLES
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#define NUM_A_TABLES 16
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#define NUM_B_TABLES 32
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#define NUM_C_TABLES 64
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#else
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unsigned int NUM_A_TABLES, NUM_B_TABLES, NUM_C_TABLES;
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#endif /* FIXED_NTABLES */
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/*
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* This determines our total virtual mapping capacity.
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@ -728,6 +732,20 @@ pmap_bootstrap(nextva)
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* Allocate user MMU tables.
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* These must be contiguous with the preceeding.
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*/
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#ifndef FIXED_NTABLES
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/*
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* The number of user-level C tables that should be allocated is
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* related to the size of physical memory. In general, there should
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* be enough tables to map four times the amount of available RAM.
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* The extra amount is needed because some table space is wasted by
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* fragmentation.
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*/
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NUM_C_TABLES = (total_phys_mem * 4) / (MMU_C_TBL_SIZE * MMU_PAGE_SIZE);
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NUM_B_TABLES = NUM_C_TABLES / 2;
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NUM_A_TABLES = NUM_B_TABLES / 2;
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#endif /* !FIXED_NTABLES */
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size = sizeof(mmu_short_pte_t) * MMU_C_TBL_SIZE * NUM_C_TABLES;
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mmuCbase = pmap_bootstrap_alloc(size);
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@ -1368,7 +1386,7 @@ free_a_table(a_tbl, relink)
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/*
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* Flush the ATC cache of all cached descriptors derived
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* from this table.
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* XXX - Sun3x does not use 68851's cached table feature
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* Sun3x does not use 68851's cached table feature
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* flush_atc_crp(mmu_vtop(a_tbl->dte));
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*/
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@ -1376,7 +1394,7 @@ free_a_table(a_tbl, relink)
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* Remove any pending cache flushes that were designated
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* for the pmap this A table belongs to.
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* a_tbl->parent->atc_flushq[0] = 0;
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* XXX - Not implemented in sun3x.
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* Not implemented in sun3x.
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*/
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/*
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@ -1600,53 +1618,6 @@ pmap_remove_pte(pte)
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pte->attr.raw = MMU_DT_INVALID;
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}
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#if 0 /* XXX - I am eliminating this function. -j */
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/* pmap_dereference_pte INTERNAL
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**
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* Update the necessary reference counts in any tables and pmaps to
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* reflect the removal of the given pte. Only called when no knowledge of
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* the pte's associated pmap is unknown. This only occurs in the PV call
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* 'pmap_page_protect()' with a protection of VM_PROT_NONE, which means
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* that all references to a given physical page must be removed.
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*/
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void
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pmap_dereference_pte(pte)
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mmu_short_pte_t *pte;
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{
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vm_offset_t va;
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c_tmgr_t *c_tbl;
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pmap_t pmap;
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va = pmap_get_pteinfo(pte, &pmap, &c_tbl);
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/*
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* Flush the translation cache of the page mapped by the PTE, should
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* it prove to be in the current pmap. Kernel mappings appear in
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* all address spaces, so they always should be flushed
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*/
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if (pmap == pmap_kernel() || pmap == current_pmap())
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TBIS(va);
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/*
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* If the mapping belongs to a user map, update the necessary
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* reference counts in the table manager. XXX - It would be
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* much easier to keep the resident count in the c_tmgr_t -gwr
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*/
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if (pmap != pmap_kernel()) {
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/*
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* Most of the situations in which pmap_dereference_pte() is
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* called are usually temporary removals of a mapping. Often
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* the mapping is reinserted shortly afterwards. If the parent
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* C table's valid entry count reaches zero as a result of
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* removing this mapping, we could return it to the free pool,
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* but we leave it alone because it is likely to be used as
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* stated above.
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*/
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c_tbl->ct_ecnt--;
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pmap->pm_stats.resident_count--;
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}
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}
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#endif 0 /* function elimination */
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/* pmap_stroll INTERNAL
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**
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* Retrieve the addresses of all table managers involved in the mapping of
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@ -1744,9 +1715,9 @@ pmap_enter(pmap, va, pa, prot, wired)
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pa &= MMU_PAGE_MASK;
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/*
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* Determine if the physical address being mapped is managed.
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* If it isn't, the mapping should be cache inhibited. (This is
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* applied later in the function.) XXX - Why non-cached? -gwr
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* Determine if the physical address being mapped is on-board RAM.
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* Any other area of the address space is likely to belong to a
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* device and hence it would be disasterous to cache its contents.
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*/
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if ((managed = is_managed(pa)) == FALSE)
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flags |= PMAP_NC;
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@ -2102,7 +2073,7 @@ pmap_enter_kernel(va, pa, prot)
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*/
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pte_idx = (u_long) _btop(va - KERNBASE);
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/* XXX - This array is traditionally named "Sysmap" */
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/* This array is traditionally named "Sysmap" */
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pte = &kernCbase[pte_idx];
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s = splimp();
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@ -2594,14 +2565,6 @@ pmap_release(pmap)
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* which always should be the case whenever
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* this function is called, there really should
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* be nothing to do.
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*
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* XXX - This function is being called while there are
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* still valid mappings, so I guess the above must not
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* be true.
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* XXX - Unless the mappings persist due to a bug here...
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* + That's what was happening. The map had no mappings,
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* but it still had an A table. pmap_remove() was not
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* releasing tables when they were empty.
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*/
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#ifdef PMAP_DEBUG
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if (pmap == NULL)
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@ -2917,21 +2880,6 @@ pmap_get_pteinfo(idx, pmap, tbl)
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return va;
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}
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#if 0 /* XXX - I am eliminating this function. */
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/* pmap_find_tic INTERNAL
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**
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* Given the address of a pte, find the TIC (level 'C' table index) for
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* the pte within its C table.
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*/
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char
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pmap_find_tic(pte)
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mmu_short_pte_t *pte;
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{
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return ((pte - mmuCbase) % MMU_C_TBL_SIZE);
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}
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#endif /* 0 */
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/* pmap_clear_modify INTERFACE
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**
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* Clear the modification bit on the page at the specified
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