From: jca <jca@openbsd.org>
Date: Wed, 13 Dec 2023 18:26:41 +0000 (+0000)
Subject: Implement per-CPU caching for the page table page (vp) pool and the PTE
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=7c73d09c2efe0a1049f5556da74181668d20a1fb;p=openbsd

Implement per-CPU caching for the page table page (vp) pool and the PTE
descriptor (pted) pool in the [riscv64] pmap implementation.  This
significantly reduces the side-effects of lock contention on the kernel
map lock that is (incorrectly) translated into excessive page daemon
wakeups.  This is not a perfect solution but it does lead to significant
speedups [on the Hifive Unmatched]

Improvement and commit message adapted from kettenis' rev 1.110 commit
to arm64/pmap.c.  ok phessler@ kettenis@
---

diff --git a/sys/arch/riscv64/include/pmap.h b/sys/arch/riscv64/include/pmap.h
index fcfd60d63be..1f52a260ee5 100644
--- a/sys/arch/riscv64/include/pmap.h
+++ b/sys/arch/riscv64/include/pmap.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pmap.h,v 1.9 2023/12/11 22:12:53 kettenis Exp $	*/
+/*	$OpenBSD: pmap.h,v 1.10 2023/12/13 18:26:41 jca Exp $	*/
 
 /*
  * Copyright (c) 2019-2020 Brian Bamsch <bbamsch@google.com>
@@ -111,10 +111,10 @@ void pmap_physload_avail(void);
 struct pv_entry;
 
 /* investigate */
-#define pmap_init_percpu()		do { /* nothing */ } while (0)
 #define pmap_unuse_final(p)		do { /* nothing */ } while (0)
 int	pmap_fault_fixup(pmap_t, vaddr_t, vm_prot_t);
 void	pmap_postinit(void);
+void	pmap_init_percpu(void);
 
 #endif /* _KERNEL && !_LOCORE */
 
diff --git a/sys/arch/riscv64/riscv64/pmap.c b/sys/arch/riscv64/riscv64/pmap.c
index 30db5d9b76b..1e33584f729 100644
--- a/sys/arch/riscv64/riscv64/pmap.c
+++ b/sys/arch/riscv64/riscv64/pmap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pmap.c,v 1.36 2023/11/28 09:10:18 jsg Exp $	*/
+/*	$OpenBSD: pmap.c,v 1.37 2023/12/13 18:26:41 jca Exp $	*/
 
 /*
  * Copyright (c) 2019-2020 Brian Bamsch <bbamsch@google.com>
@@ -1773,6 +1773,13 @@ pmap_postinit(void)
 	    npages * PAGE_SIZE, VM_MAP_INTRSAFE, FALSE, NULL);
 }
 
+void
+pmap_init_percpu(void)
+{
+	pool_cache_init(&pmap_pted_pool);
+	pool_cache_init(&pmap_vp_pool);
+}
+
 void
 pmap_update(pmap_t pm)
 {