Date: Thu, 01 Oct 2020 12:22:25 -0700 From: Ravi Pokala <rpokala@freebsd.org> To: Bryan Drewery <bdrewery@FreeBSD.org>, <src-committers@freebsd.org>, <svn-src-all@freebsd.org>, <svn-src-head@freebsd.org> Subject: Re: svn commit: r366340 - head/sys/kern Message-ID: <722E6718-7A24-4D15-84A8-C769C220EDCB@panasas.com> In-Reply-To: <202010011917.091JH3jX031245@repo.freebsd.org> References: <202010011917.091JH3jX031245@repo.freebsd.org>
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If you changed it to bool, shouldn't you be using "true" and "false"?
Thanks,
Ravi (rpokala@)
=EF=BB=BF-----Original Message-----
From: <owner-src-committers@freebsd.org> on behalf of Bryan Drewery <bdrewe=
ry@FreeBSD.org>
Date: 2020-10-01, Thursday at 12:17
To: <src-committers@freebsd.org>, <svn-src-all@freebsd.org>, <svn-src-head@=
freebsd.org>
Subject: svn commit: r366340 - head/sys/kern
Author: bdrewery
Date: Thu Oct 1 19:17:03 2020
New Revision: 366340
URL: https://svnweb.freebsd.org/changeset/base/366340
Log:
Use unlocked page lookup for inmem() to avoid object lock contention
Reviewed By: kib, markj
Sponsored by: Dell EMC Isilon
Submitted by: mlaier
Differential Revision: https://reviews.freebsd.org/D26597
Modified:
head/sys/kern/vfs_bio.c
Modified: head/sys/kern/vfs_bio.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D
--- head/sys/kern/vfs_bio.c Thu Oct 1 19:06:07 2020 (r366339)
+++ head/sys/kern/vfs_bio.c Thu Oct 1 19:17:03 2020 (r366340)
@@ -154,7 +154,7 @@ caddr_t __read_mostly unmapped_buf;
/* Used below and for softdep flushing threads in ufs/ffs/ffs_softdep.=
c */
struct proc *bufdaemonproc;
-static int inmem(struct vnode *vp, daddr_t blkno);
+static bool inmem(struct vnode *vp, daddr_t blkno);
static void vm_hold_free_pages(struct buf *bp, int newbsize);
static void vm_hold_load_pages(struct buf *bp, vm_offset_t from,
vm_offset_t to);
@@ -3586,20 +3586,21 @@ incore(struct bufobj *bo, daddr_t blkno)
* it also hunts around in the VM system for the data.
*/
-static int
+static bool
inmem(struct vnode * vp, daddr_t blkno)
{
vm_object_t obj;
vm_offset_t toff, tinc, size;
- vm_page_t m;
+ vm_page_t m, n;
vm_ooffset_t off;
+ int valid;
ASSERT_VOP_LOCKED(vp, "inmem");
if (incore(&vp->v_bufobj, blkno))
- return 1;
+ return (1);
if (vp->v_mount =3D=3D NULL)
- return 0;
+ return (0);
obj =3D vp->v_object;
if (obj =3D=3D NULL)
return (0);
@@ -3609,24 +3610,30 @@ inmem(struct vnode * vp, daddr_t blkno)
size =3D vp->v_mount->mnt_stat.f_iosize;
off =3D (vm_ooffset_t)blkno * (vm_ooffset_t)vp->v_mount->mnt_stat.f_ios=
ize;
- VM_OBJECT_RLOCK(obj);
for (toff =3D 0; toff < vp->v_mount->mnt_stat.f_iosize; toff +=3D tinc) {
- m =3D vm_page_lookup(obj, OFF_TO_IDX(off + toff));
- if (!m)
- goto notinmem;
+ m =3D vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff));
+recheck:
+ if (m =3D=3D NULL)
+ return (0);
+ /*
+ * Consider page validity only if page mapping didn't change
+ * during the check.
+ */
+ valid =3D vm_page_is_valid(m,
+ (vm_offset_t)((toff + off) & PAGE_MASK), tinc);
+ n =3D vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff));
+ if (m !=3D n) {
+ m =3D n;
+ goto recheck;
+ }
+ if (!valid)
+ return (0);
+
tinc =3D size;
if (tinc > PAGE_SIZE - ((toff + off) & PAGE_MASK))
tinc =3D PAGE_SIZE - ((toff + off) & PAGE_MASK);
- if (vm_page_is_valid(m,
- (vm_offset_t) ((toff + off) & PAGE_MASK), tinc) =3D=3D 0)
- goto notinmem;
}
- VM_OBJECT_RUNLOCK(obj);
- return 1;
-
-notinmem:
- VM_OBJECT_RUNLOCK(obj);
- return (0);
+ return (1);
}
/*
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