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Use unlocked page lookup for inmem() to avoid object lock contention

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Reviewed By:	kib, markj
Sponsored by:	Dell EMC Isilon
Submitted by:	mlaier
Differential Revision:	https://reviews.freebsd.org/D26597
This commit is contained in:
Bryan Drewery 2020-10-01 19:17:03 +00:00
parent 8833aad7be
commit 2398cd1103
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=366340
1 changed files with 25 additions and 18 deletions
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43
sys/kern/vfs_bio.c
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@ -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 == NULL)
return 0;
return (0);
obj = vp->v_object;
if (obj == NULL)
return (0);
@ -3609,24 +3610,30 @@ inmem(struct vnode * vp, daddr_t blkno)
size = vp->v_mount->mnt_stat.f_iosize;
off = (vm_ooffset_t)blkno * (vm_ooffset_t)vp->v_mount->mnt_stat.f_iosize;
VM_OBJECT_RLOCK(obj);
for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) {
m = vm_page_lookup(obj, OFF_TO_IDX(off + toff));
if (!m)
goto notinmem;
m = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff));
recheck:
if (m == NULL)
return (0);
/*
* Consider page validity only if page mapping didn't change
* during the check.
*/
valid = vm_page_is_valid(m,
(vm_offset_t)((toff + off) & PAGE_MASK), tinc);
n = vm_page_lookup_unlocked(obj, OFF_TO_IDX(off + toff));
if (m != n) {
m = n;
goto recheck;
}
if (!valid)
return (0);
tinc = size;
if (tinc > PAGE_SIZE - ((toff + off) & PAGE_MASK))
tinc = PAGE_SIZE - ((toff + off) & PAGE_MASK);
if (vm_page_is_valid(m,
(vm_offset_t) ((toff + off) & PAGE_MASK), tinc) == 0)
goto notinmem;
}
VM_OBJECT_RUNLOCK(obj);
return 1;
notinmem:
VM_OBJECT_RUNLOCK(obj);
return (0);
return (1);
}
/*