git: 1fe88bc8512b - stable/13 - amd64: Eliminate a redundant test from pmap_enter_object()
Mark Johnston
markj at FreeBSD.org
Tue Aug 31 19:09:54 UTC 2021
The branch stable/13 has been updated by markj:
URL: https://cgit.FreeBSD.org/src/commit/?id=1fe88bc8512b8444a31534f4b196a1d62af7df33
commit 1fe88bc8512b8444a31534f4b196a1d62af7df33
Author: Alan Cox <alc at FreeBSD.org>
AuthorDate: 2021-07-24 03:50:10 +0000
Commit: Mark Johnston <markj at FreeBSD.org>
CommitDate: 2021-08-31 19:09:24 +0000
amd64: Eliminate a redundant test from pmap_enter_object()
The call to pmap_allow_2m_x_page() in pmap_enter_object() is redundant.
Specifically, even without the call to pmap_allow_2m_x_page() in
pmap_enter_object(), pmap_allow_2m_x_page() is eventually called by
pmap_enter_pde(), so the outcome will be the same. Essentially,
calling pmap_allow_2m_x_page() in pmap_enter_object() amounts to
"optimizing" for the unexpected case.
Reviewed by: kib
(cherry picked from commit b7de535288362b072cf2801007e4d7e0e903d467)
---
sys/amd64/amd64/pmap.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index 9122a368823b..705bbe712bff 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -7222,7 +7222,6 @@ pmap_enter_object(pmap_t pmap, vm_offset_t start, vm_offset_t end,
va = start + ptoa(diff);
if ((va & PDRMASK) == 0 && va + NBPDR <= end &&
m->psind == 1 && pmap_ps_enabled(pmap) &&
- pmap_allow_2m_x_page(pmap, (prot & VM_PROT_EXECUTE) != 0) &&
pmap_enter_2mpage(pmap, va, m, prot, &lock))
m = &m[NBPDR / PAGE_SIZE - 1];
else
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