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Remove unnecessary object locking from the vnode pager. Recent changes to

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busy/valid/dirty locking make these acquires redundant.

Reviewed by:	kib, markj
Differential Revision:	https://reviews.freebsd.org/D22186
This commit is contained in:
jeff 2019-11-19 23:30:09 +00:00
parent be1b482c07
commit 83848ec34e
3 changed files with 9 additions and 25 deletions
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2
sys/vm/vm_page.c
View File

@ -4527,7 +4527,7 @@ vm_page_bits(int base, int size)
((vm_page_bits_t)1 << first_bit));
}
static inline void
void
vm_page_bits_set(vm_page_t m, vm_page_bits_t *bits, vm_page_bits_t set)
{

1
sys/vm/vm_page.h
View File

@ -587,6 +587,7 @@ vm_page_t vm_page_alloc_contig_domain(vm_object_t object,
vm_memattr_t memattr);
vm_page_t vm_page_alloc_freelist(int, int);
vm_page_t vm_page_alloc_freelist_domain(int, int, int);
void vm_page_bits_set(vm_page_t m, vm_page_bits_t *bits, vm_page_bits_t set);
bool vm_page_blacklist_add(vm_paddr_t pa, bool verbose);
void vm_page_change_lock(vm_page_t m, struct mtx **mtx);
vm_page_t vm_page_grab (vm_object_t, vm_pindex_t, int);

31
sys/vm/vnode_pager.c
View File

@ -649,9 +649,7 @@ vnode_pager_input_smlfs(vm_object_t object, vm_page_t m)
bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize);
KASSERT((m->dirty & bits) == 0,
("vnode_pager_input_smlfs: page %p is dirty", m));
VM_OBJECT_WLOCK(object);
m->valid |= bits;
VM_OBJECT_WUNLOCK(object);
vm_page_bits_set(m, &m->valid, bits);
}
sf_buf_free(sf);
if (error) {
@ -888,9 +886,7 @@ vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int count,
pmap_zero_page(m[0]);
KASSERT(m[0]->dirty == 0, ("%s: page %p is dirty",
__func__, m[0]));
VM_OBJECT_WLOCK(object);
vm_page_valid(m[0]);
VM_OBJECT_WUNLOCK(object);
return (VM_PAGER_OK);
}
@ -1143,7 +1139,8 @@ vnode_pager_generic_getpages_done(struct buf *bp)
bp->b_data = unmapped_buf;
}
VM_OBJECT_WLOCK(object);
/* Read lock to protect size. */
VM_OBJECT_RLOCK(object);
for (i = 0, tfoff = IDX_TO_OFF(bp->b_pages[0]->pindex);
i < bp->b_npages; i++, tfoff = nextoff) {
vm_page_t mt;
@ -1180,7 +1177,7 @@ vnode_pager_generic_getpages_done(struct buf *bp)
if (i < bp->b_pgbefore || i >= bp->b_npages - bp->b_pgafter)
vm_page_readahead_finish(mt);
}
VM_OBJECT_WUNLOCK(object);
VM_OBJECT_RUNLOCK(object);
if (error != 0)
printf("%s: I/O read error %d\n", __func__, error);
@ -1304,12 +1301,6 @@ vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount,
*/
VM_OBJECT_RLOCK(object);
if (maxsize + poffset > object->un_pager.vnp.vnp_size) {
if (!VM_OBJECT_TRYUPGRADE(object)) {
VM_OBJECT_RUNLOCK(object);
VM_OBJECT_WLOCK(object);
if (maxsize + poffset <= object->un_pager.vnp.vnp_size)
goto downgrade;
}
if (object->un_pager.vnp.vnp_size > poffset) {
maxsize = object->un_pager.vnp.vnp_size - poffset;
ncount = btoc(maxsize);
@ -1317,7 +1308,7 @@ vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount,
pgoff = roundup2(pgoff, DEV_BSIZE);
/*
* If the object is locked and the following
* If the page is busy and the following
* conditions hold, then the page's dirty
* field cannot be concurrently changed by a
* pmap operation.
@ -1336,9 +1327,8 @@ vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount,
}
for (i = ncount; i < count; i++)
rtvals[i] = VM_PAGER_BAD;
downgrade:
VM_OBJECT_LOCK_DOWNGRADE(object);
}
VM_OBJECT_RUNLOCK(object);
auio.uio_iov = &aiov;
auio.uio_segflg = UIO_NOCOPY;
@ -1384,7 +1374,6 @@ start_write:
*/
MPASS(prev_offset < next_offset);
VM_OBJECT_RUNLOCK(object);
aiov.iov_base = NULL;
auio.uio_iovcnt = 1;
auio.uio_offset = prev_offset;
@ -1400,7 +1389,6 @@ start_write:
"zero-length write at %ju resid %zd\n",
auio.uio_offset, auio.uio_resid);
}
VM_OBJECT_RLOCK(object);
break;
}
@ -1418,7 +1406,6 @@ start_write:
vn_printf(vp, "vnode_pager_putpages: residual I/O %zd "
"at %ju\n", auio.uio_resid,
(uintmax_t)ma[0]->pindex);
VM_OBJECT_RLOCK(object);
if (error != 0 || auio.uio_resid != 0)
break;
}
@ -1432,7 +1419,6 @@ write_done:
/* Unwritten pages in range, free bonus if the page is clean. */
for (; i < ncount; i++)
rtvals[i] = ma[i]->dirty == 0 ? VM_PAGER_OK : VM_PAGER_ERROR;
VM_OBJECT_RUNLOCK(object);
VM_CNT_ADD(v_vnodepgsout, i);
VM_CNT_INC(v_vnodeout);
return (rtvals[0]);
@ -1482,7 +1468,6 @@ vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written, off_t eof,
if (written == 0 && eof >= lpos)
return;
obj = ma[0]->object;
VM_OBJECT_WLOCK(obj);
for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) {
if (pos < trunc_page(written)) {
rtvals[i] = VM_PAGER_OK;
@ -1494,7 +1479,7 @@ vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written, off_t eof,
}
}
if (eof >= lpos) /* avoid truncation */
goto done;
return;
for (pos = eof, i = OFF_TO_IDX(trunc_page(pos)); pos < lpos; i++) {
if (pos != trunc_page(pos)) {
/*
@ -1523,8 +1508,6 @@ vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written, off_t eof,
pos += PAGE_SIZE;
}
}
done:
VM_OBJECT_WUNLOCK(obj);
}
static void