[src/trunk]: src/sys/uvm - uvm_pagezerocheck(): put a global lock around it t...

[ad <ad%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/698149fd5075
branches:  trunk
changeset: 467041:698149fd5075
user:      ad <ad%NetBSD.org@localhost>
date:      Sat Jan 11 19:51:01 2020 +0000

description:
- uvm_pagezerocheck(): put a global lock around it to protect the single
  page mapping (DEBUG only).

- uvm_pagefree(): increment zeropages as needed.

diffstat:

 sys/uvm/uvm_page.c |  11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diffs (60 lines):

diff -r ddb4da1925d4 -r 698149fd5075 sys/uvm/uvm_page.c
--- a/sys/uvm/uvm_page.c        Sat Jan 11 19:06:34 2020 +0000
+++ b/sys/uvm/uvm_page.c        Sat Jan 11 19:51:01 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_page.c,v 1.222 2020/01/09 16:35:03 ad Exp $        */
+/*     $NetBSD: uvm_page.c,v 1.223 2020/01/11 19:51:01 ad Exp $        */
 
 /*-
  * Copyright (c) 2019 The NetBSD Foundation, Inc.
@@ -95,7 +95,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_page.c,v 1.222 2020/01/09 16:35:03 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_page.c,v 1.223 2020/01/11 19:51:01 ad Exp $");
 
 #include "opt_ddb.h"
 #include "opt_uvm.h"
@@ -181,6 +181,7 @@
 } *uvm_page_numa_region;
 
 #ifdef DEBUG
+kmutex_t uvm_zerochecklock __cacheline_aligned;
 vaddr_t uvm_zerocheckkva;
 #endif /* DEBUG */
 
@@ -439,6 +440,7 @@
         */
        uvm_zerocheckkva = *kvm_startp;
        *kvm_startp += PAGE_SIZE;
+       mutex_init(&uvm_zerochecklock, MUTEX_DEFAULT, IPL_VM);
 #endif /* DEBUG */
 
        /*
@@ -1419,6 +1421,7 @@
         *
         * it might be better to have "CPU-local temporary map" pmap interface.
         */
+       mutex_spin_enter(&uvm_zerochecklock);
        pmap_kenter_pa(uvm_zerocheckkva, VM_PAGE_TO_PHYS(pg), VM_PROT_READ, 0);
        p = (int *)uvm_zerocheckkva;
        ep = (int *)((char *)p + PAGE_SIZE);
@@ -1429,6 +1432,7 @@
                p++;
        }
        pmap_kremove(uvm_zerocheckkva, PAGE_SIZE);
+       mutex_spin_exit(&uvm_zerochecklock);
        /*
         * pmap_update() is not necessary here because no one except us
         * uses this VA.
@@ -1574,6 +1578,9 @@
 
        /* Try to send the page to the per-CPU cache. */
        s = splvm();
+       if (pg->flags & PG_ZERO) {
+               CPU_COUNT(CPU_COUNT_ZEROPAGES, 1);
+       }
        ucpu = curcpu()->ci_data.cpu_uvm;
        bucket = uvm_page_get_bucket(pg);
        if (bucket == ucpu->pgflbucket && uvm_pgflcache_free(ucpu, pg)) {