svn commit: r351921 - head/sys/powerpc/aim
Justin Hibbits
jhibbits at FreeBSD.org
Fri Sep 6 02:45:47 UTC 2019
Author: jhibbits
Date: Fri Sep 6 02:45:46 2019
New Revision: 351921
URL: https://svnweb.freebsd.org/changeset/base/351921
Log:
powerpc64/pmap: Simplify the code path for moea64_pte_replace_native()
Summary:
MOEA64_PTE_REPLACE() is called often with the pmap lock held, and
sometimes with the page pv lock held. The less work done while holding
a lock, the better. Since we are intending to replace the same PTE
(same hash index), we don't need to recalculate anything, just flat
replace the PTE. This cuts more than 200 instructions off the
invalidating code path. In addition, we don't need to replace a PTE
that's not occupied by this PVO.
Reviewed by: luporl
Differential Revision: https://reviews.freebsd.org/D21515
Modified:
head/sys/powerpc/aim/moea64_native.c
Modified: head/sys/powerpc/aim/moea64_native.c
==============================================================================
--- head/sys/powerpc/aim/moea64_native.c Fri Sep 6 02:28:03 2019 (r351920)
+++ head/sys/powerpc/aim/moea64_native.c Fri Sep 6 02:45:46 2019 (r351921)
@@ -358,6 +358,45 @@ moea64_pte_unset_native(mmu_t mmu, struct pvo_entry *p
}
static int64_t
+moea64_pte_replace_inval_native(mmu_t mmu, struct pvo_entry *pvo,
+ volatile struct lpte *pt)
+{
+ struct lpte properpt;
+ uint64_t ptelo;
+
+ moea64_pte_from_pvo(pvo, &properpt);
+
+ rw_rlock(&moea64_eviction_lock);
+ if ((be64toh(pt->pte_hi & LPTE_AVPN_MASK)) !=
+ (properpt.pte_hi & LPTE_AVPN_MASK)) {
+ /* Evicted */
+ STAT_MOEA64(moea64_pte_overflow--);
+ rw_runlock(&moea64_eviction_lock);
+ return (-1);
+ }
+
+ /*
+ * Replace the pte, briefly locking it to collect RC bits. No
+ * atomics needed since this is protected against eviction by the lock.
+ */
+ isync();
+ critical_enter();
+ pt->pte_hi = be64toh((pt->pte_hi & ~LPTE_VALID) | LPTE_LOCKED);
+ PTESYNC();
+ TLBIE(pvo->pvo_vpn);
+ ptelo = be64toh(pt->pte_lo);
+ EIEIO();
+ pt->pte_lo = htobe64(properpt.pte_lo);
+ EIEIO();
+ pt->pte_hi = htobe64(properpt.pte_hi); /* Release lock */
+ PTESYNC();
+ critical_exit();
+ rw_runlock(&moea64_eviction_lock);
+
+ return (ptelo & (LPTE_CHG | LPTE_REF));
+}
+
+static int64_t
moea64_pte_replace_native(mmu_t mmu, struct pvo_entry *pvo, int flags)
{
volatile struct lpte *pt = moea64_pteg_table + pvo->pvo_pte.slot;
@@ -379,8 +418,7 @@ moea64_pte_replace_native(mmu_t mmu, struct pvo_entry
rw_runlock(&moea64_eviction_lock);
} else {
/* Otherwise, need reinsertion and deletion */
- ptelo = moea64_pte_unset_native(mmu, pvo);
- moea64_pte_insert_native(mmu, pvo);
+ ptelo = moea64_pte_replace_inval_native(mmu, pvo, pt);
}
return (ptelo);
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