Date: Fri, 13 Jun 2025 17:32:40 GMT
From: Alan Cox <alc@FreeBSD.org>
To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org
Subject: git: b7536f9593a3 - main - arm64 pmap: Simplify pmap_demote_l{2,3}c()
Message-ID: <202506131732.55DHWeGV009093@gitrepo.freebsd.org>
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The branch main has been updated by alc: URL: https://cgit.FreeBSD.org/src/commit/?id=b7536f9593a30b8253546214f53c9ef063c656a9 commit b7536f9593a30b8253546214f53c9ef063c656a9 Author: Alan Cox <alc@FreeBSD.org> AuthorDate: 2025-06-09 06:34:13 +0000 Commit: Alan Cox <alc@FreeBSD.org> CommitDate: 2025-06-13 17:31:53 +0000 arm64 pmap: Simplify pmap_demote_l{2,3}c() Simplify the loop for remaking the mappings in pmap_demote_l{2,3}c(). Since the mappings are invalid, we needn't use an atomic read-modify- write operation to remake the mappings. The accessed and dirty bits won't concurrently change. --- sys/arm64/arm64/pmap.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/sys/arm64/arm64/pmap.c b/sys/arm64/arm64/pmap.c index f8e422848e94..3529314b07c7 100644 --- a/sys/arm64/arm64/pmap.c +++ b/sys/arm64/arm64/pmap.c @@ -8662,10 +8662,10 @@ pmap_demote_l2c(pmap_t pmap, pt_entry_t *l2p, vm_offset_t va) /* * Remake the mappings, updating the accessed and dirty bits. */ + l2e = (pmap_load(l2c_start) & ~mask) | nbits; for (tl2p = l2c_start; tl2p < l2c_end; tl2p++) { - l2e = pmap_load(tl2p); - while (!atomic_fcmpset_64(tl2p, &l2e, (l2e & ~mask) | nbits)) - cpu_spinwait(); + pmap_store(tl2p, l2e); + l2e += L2_SIZE; } dsb(ishst); @@ -8751,10 +8751,10 @@ pmap_demote_l3c(pmap_t pmap, pt_entry_t *l3p, vm_offset_t va) /* * Remake the mappings, updating the accessed and dirty bits. */ + l3e = (pmap_load(l3c_start) & ~mask) | nbits; for (tl3p = l3c_start; tl3p < l3c_end; tl3p++) { - l3e = pmap_load(tl3p); - while (!atomic_fcmpset_64(tl3p, &l3e, (l3e & ~mask) | nbits)) - cpu_spinwait(); + pmap_store(tl3p, l3e); + l3e += L3_SIZE; } dsb(ishst);
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