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Add uvm_pagewanted_p(): return true if someone is waiting on the page and

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assert caller has correct lock to observe that.
This commit is contained in:
ad 2020-05-24 19:46:59 +00:00
parent 5606745f92
commit 232803aa39
2 changed files with 20 additions and 4 deletions
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21
sys/uvm/uvm_page.c
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@ -1,4 +1,4 @@
/* $NetBSD: uvm_page.c,v 1.237 2020/05/19 20:46:39 ad Exp $ */
/* $NetBSD: uvm_page.c,v 1.238 2020/05/24 19:46:59 ad Exp $ */
/*-
* Copyright (c) 2019, 2020 The NetBSD Foundation, Inc.
@ -95,7 +95,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uvm_page.c,v 1.237 2020/05/19 20:46:39 ad Exp $");
__KERNEL_RCSID(0, "$NetBSD: uvm_page.c,v 1.238 2020/05/24 19:46:59 ad Exp $");
#include "opt_ddb.h"
#include "opt_uvm.h"
@ -1718,8 +1718,8 @@ uvm_pagewait(struct vm_page *pg, krwlock_t *lock, const char *wmesg)
KASSERT(uvm_page_owner_locked_p(pg, false));
mutex_enter(&pg->interlock);
rw_exit(lock);
pg->pqflags |= PQ_WANTED;
rw_exit(lock);
UVM_UNLOCK_AND_WAIT(pg, &pg->interlock, false, wmesg, 0);
}
@ -1744,6 +1744,21 @@ uvm_pagewakeup(struct vm_page *pg)
}
}
/*
* uvm_pagewanted_p: return true if someone is waiting on the page
*
* => object must be write locked (lock out all concurrent access)
*/
bool
uvm_pagewanted_p(struct vm_page *pg)
{
KASSERT(uvm_page_owner_locked_p(pg, true));
return (atomic_load_relaxed(&pg->pqflags) & PQ_WANTED) != 0;
}
#if defined(UVM_PAGE_TRKOWN)
/*
* uvm_page_own: set or release page ownership

3
sys/uvm/uvm_page.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: uvm_page.h,v 1.103 2020/05/17 19:38:17 ad Exp $ */
/* $NetBSD: uvm_page.h,v 1.104 2020/05/24 19:46:59 ad Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
@ -378,6 +378,7 @@ bool uvm_pagecheckdirty(struct vm_page *, bool);
bool uvm_pagereadonly_p(struct vm_page *);
bool uvm_page_locked_p(struct vm_page *);
void uvm_pagewakeup(struct vm_page *);
bool uvm_pagewanted_p(struct vm_page *);
void uvm_pagewait(struct vm_page *, krwlock_t *, const char *);
int uvm_page_lookup_freelist(struct vm_page *);