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 fcfd60d..1f52a26 100644 (file)
--- 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 30db5d9..1e33584 100644 (file)
--- 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)
 {