riscv: optimize MADV_WILLNEED on existing superpages
Specifically, avoid pointless calls to pmap_enter_quick_locked() when
madvise(MADV_WILLNEED) is applied to an existing superpage mapping.
1d5ebad06c
made the change for amd64 and arm64.
Reviewed by: markj, alc
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D36563
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@ -3120,13 +3120,12 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
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}
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/*
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* Tries to create a read- and/or execute-only 2MB page mapping. Returns true
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* if successful. Returns false if (1) a page table page cannot be allocated
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* without sleeping, (2) a mapping already exists at the specified virtual
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* address, or (3) a PV entry cannot be allocated without reclaiming another
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* PV entry.
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* Tries to create a read- and/or execute-only 2MB page mapping. Returns
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* KERN_SUCCESS if the mapping was created. Otherwise, returns an error
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* value. See pmap_enter_l2() for the possible error values when "no sleep",
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* "no replace", and "no reclaim" are specified.
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*/
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static bool
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static int
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pmap_enter_2mpage(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
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struct rwlock **lockp)
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{
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@ -3144,18 +3143,20 @@ pmap_enter_2mpage(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
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if (va < VM_MAXUSER_ADDRESS)
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new_l2 |= PTE_U;
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return (pmap_enter_l2(pmap, va, new_l2, PMAP_ENTER_NOSLEEP |
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PMAP_ENTER_NOREPLACE | PMAP_ENTER_NORECLAIM, NULL, lockp) ==
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KERN_SUCCESS);
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PMAP_ENTER_NOREPLACE | PMAP_ENTER_NORECLAIM, NULL, lockp));
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}
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/*
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* Tries to create the specified 2MB page mapping. Returns KERN_SUCCESS if
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* the mapping was created, and either KERN_FAILURE or KERN_RESOURCE_SHORTAGE
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* otherwise. Returns KERN_FAILURE if PMAP_ENTER_NOREPLACE was specified and
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* a mapping already exists at the specified virtual address. Returns
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* KERN_RESOURCE_SHORTAGE if PMAP_ENTER_NOSLEEP was specified and a page table
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* page allocation failed. Returns KERN_RESOURCE_SHORTAGE if
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* PMAP_ENTER_NORECLAIM was specified and a PV entry allocation failed.
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* the mapping was created, and one of KERN_FAILURE, KERN_NO_SPACE, or
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* KERN_RESOURCE_SHORTAGE otherwise. Returns KERN_FAILURE if
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* PMAP_ENTER_NOREPLACE was specified and a 4KB page mapping already exists
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* within the 2MB virtual address range starting at the specified virtual
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* address. Returns KERN_NO_SPACE if PMAP_ENTER_NOREPLACE was specified and a
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* 2MB page mapping already exists at the specified virtual address. Returns
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* KERN_RESOURCE_SHORTAGE if either (1) PMAP_ENTER_NOSLEEP was specified and a
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* page table page allocation failed or (2) PMAP_ENTER_NORECLAIM was specified
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* and a PV entry allocation failed.
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*
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* The parameter "m" is only used when creating a managed, writeable mapping.
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*/
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@ -3183,11 +3184,19 @@ pmap_enter_l2(pmap_t pmap, vm_offset_t va, pd_entry_t new_l2, u_int flags,
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KASSERT(l2pg->ref_count > 1,
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("pmap_enter_l2: l2pg's ref count is too low"));
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if ((flags & PMAP_ENTER_NOREPLACE) != 0) {
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l2pg->ref_count--;
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CTR2(KTR_PMAP,
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"pmap_enter_l2: failed to replace existing mapping"
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" for va %#lx in pmap %p", va, pmap);
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return (KERN_FAILURE);
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if ((oldl2 & PTE_RWX) != 0) {
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l2pg->ref_count--;
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CTR2(KTR_PMAP,
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"pmap_enter_l2: no space for va %#lx"
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" in pmap %p", va, pmap);
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return (KERN_NO_SPACE);
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} else {
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l2pg->ref_count--;
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CTR2(KTR_PMAP, "pmap_enter_l2:"
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" failed to replace existing mapping"
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" for va %#lx in pmap %p", va, pmap);
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return (KERN_FAILURE);
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}
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}
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SLIST_INIT(&free);
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if ((oldl2 & PTE_RWX) != 0)
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@ -3280,6 +3289,7 @@ pmap_enter_object(pmap_t pmap, vm_offset_t start, vm_offset_t end,
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vm_offset_t va;
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vm_page_t m, mpte;
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vm_pindex_t diff, psize;
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int rv;
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VM_OBJECT_ASSERT_LOCKED(m_start->object);
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@ -3293,7 +3303,8 @@ pmap_enter_object(pmap_t pmap, vm_offset_t start, vm_offset_t end,
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va = start + ptoa(diff);
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if ((va & L2_OFFSET) == 0 && va + L2_SIZE <= end &&
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m->psind == 1 && pmap_ps_enabled(pmap) &&
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pmap_enter_2mpage(pmap, va, m, prot, &lock))
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((rv = pmap_enter_2mpage(pmap, va, m, prot, &lock)) ==
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KERN_SUCCESS || rv == KERN_NO_SPACE))
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m = &m[L2_SIZE / PAGE_SIZE - 1];
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else
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mpte = pmap_enter_quick_locked(pmap, va, m, prot, mpte,
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