The branch main has been updated by alc:
URL:
https://cgit.FreeBSD.org/src/commit/?id=41dfea24eec242e1e083e2a879483a7c05c7e2ff
commit 41dfea24eec242e1e083e2a879483a7c05c7e2ff
Author: Alan Cox <a...@freebsd.org>
AuthorDate: 2024-06-01 18:17:52 +0000
Commit: Alan Cox <a...@freebsd.org>
CommitDate: 2024-06-05 04:25:51 +0000
arm64 pmap: Enable L3C promotions by pmap_enter_quick()
More precisely, implement L3C (64KB/2MB, depending on base page size)
promotion in pmap_enter_quick()'s helper function,
pmap_enter_quick_locked(). At the same time, use the recently
introduced flag VM_PROT_NO_PROMOTE from pmap_enter_object() to
pmap_enter_quick_locked() to avoid L3C promotion attempts that will
fail.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D45445
---
sys/arm64/arm64/pmap.c | 29 +++++++++++++++++++++++------
1 file changed, 23 insertions(+), 6 deletions(-)
diff --git a/sys/arm64/arm64/pmap.c b/sys/arm64/arm64/pmap.c
index 03d0a1cc6676..8ac7b8f6a135 100644
--- a/sys/arm64/arm64/pmap.c
+++ b/sys/arm64/arm64/pmap.c
@@ -5883,9 +5883,19 @@ pmap_enter_object(pmap_t pmap, vm_offset_t start,
vm_offset_t end,
((rv = pmap_enter_l3c_rx(pmap, va, m, &mpte, prot,
&lock)) == KERN_SUCCESS || rv == KERN_NO_SPACE))
m = &m[L3C_ENTRIES - 1];
- else
- mpte = pmap_enter_quick_locked(pmap, va, m, prot, mpte,
- &lock);
+ else {
+ /*
+ * In general, if a superpage mapping were possible,
+ * it would have been created above. That said, if
+ * start and end are not superpage aligned, then
+ * promotion might be possible at the ends of [start,
+ * end). However, in practice, those promotion
+ * attempts are so unlikely to succeed that they are
+ * not worth trying.
+ */
+ mpte = pmap_enter_quick_locked(pmap, va, m, prot |
+ VM_PROT_NO_PROMOTE, mpte, &lock);
+ }
m = TAILQ_NEXT(m, listq);
}
if (lock != NULL)
@@ -6048,12 +6058,19 @@ pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va,
vm_page_t m,
#if VM_NRESERVLEVEL > 0
/*
- * If both the PTP and the reservation are fully populated, then
- * attempt promotion.
+ * First, attempt L3C promotion, if the virtual and physical addresses
+ * are aligned with each other and an underlying reservation has the
+ * neighboring L3 pages allocated. The first condition is simply an
+ * optimization that recognizes some eventual promotion failures early
+ * at a lower run-time cost. Then, attempt L2 promotion, if both the
+ * PTP and the reservation are fully populated.
*/
if ((prot & VM_PROT_NO_PROMOTE) == 0 &&
- (mpte == NULL || mpte->ref_count == NL3PG) &&
+ (va & L3C_OFFSET) == (pa & L3C_OFFSET) &&
(m->flags & PG_FICTITIOUS) == 0 &&
+ vm_reserv_is_populated(m, L3C_ENTRIES) &&
+ pmap_promote_l3c(pmap, l3, va) &&
+ (mpte == NULL || mpte->ref_count == NL3PG) &&
vm_reserv_level_iffullpop(m) == 0) {
if (l2 == NULL)
l2 = pmap_pde(pmap, va, &lvl);
