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Reorganize the code in bdwrite() which handles move of dirtiness

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from the buffer pages to buffer. Combine the code to set buffer
dirty range (previously in vfs_setdirty()) and to clean the pages
(vfs_clean_pages()) into new function vfs_clean_pages_dirty_buf(). Now
the vm object lock is acquired only once.

Drain the VPO_BUSY bit of the buffer pages before setting valid
and clean bits in vfs_clean_pages_dirty_buf() with new helper
vfs_drain_busy_pages(). pmap_clear_modify() asserts that page is not
busy.

In vfs_busy_pages(), move the wait for draining of VPO_BUSY before
the dirtyness handling, to follow the structure of
vfs_clean_pages_dirty_buf().

Reported and tested by:	pho
Suggested and reviewed by:	alc
MFC after:	2 weeks
This commit is contained in:
kib 2010-06-08 17:54:28 +00:00
parent 9a18b596b8
commit 317abde372
1 changed files with 65 additions and 70 deletions
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135
sys/kern/vfs_bio.c
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@ -102,8 +102,8 @@ static void vm_hold_load_pages(struct buf *bp, vm_offset_t from,
static void vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, vm_page_t m);
static void vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off,
vm_page_t m);
static void vfs_clean_pages(struct buf *bp);
static void vfs_setdirty(struct buf *bp);
static void vfs_drain_busy_pages(struct buf *bp);
static void vfs_clean_pages_dirty_buf(struct buf *bp);
static void vfs_setdirty_locked_object(struct buf *bp);
static void vfs_vmio_release(struct buf *bp);
static int vfs_bio_clcheck(struct vnode *vp, int size,
@ -1025,18 +1025,17 @@ bdwrite(struct buf *bp)
}
/*
* Set the *dirty* buffer range based upon the VM system dirty pages.
* Set the *dirty* buffer range based upon the VM system dirty
* pages.
*
* Mark the buffer pages as clean. We need to do this here to
* satisfy the vnode_pager and the pageout daemon, so that it
* thinks that the pages have been "cleaned". Note that since
* the pages are in a delayed write buffer -- the VFS layer
* "will" see that the pages get written out on the next sync,
* or perhaps the cluster will be completed.
*/
vfs_setdirty(bp);
/*
* We need to do this here to satisfy the vnode_pager and the
* pageout daemon, so that it thinks that the pages have been
* "cleaned". Note that since the pages are in a delayed write
* buffer -- the VFS layer "will" see that the pages get written
* out on the next sync, or perhaps the cluster will be completed.
*/
vfs_clean_pages(bp);
vfs_clean_pages_dirty_buf(bp);
bqrelse(bp);
/*
@ -2398,31 +2397,44 @@ inmem(struct vnode * vp, daddr_t blkno)
}
/*
* vfs_setdirty:
* Set the dirty range for a buffer based on the status of the dirty
* bits in the pages comprising the buffer. The range is limited
* to the size of the buffer.
*
* Sets the dirty range for a buffer based on the status of the dirty
* bits in the pages comprising the buffer.
* Tell the VM system that the pages associated with this buffer
* are clean. This is used for delayed writes where the data is
* going to go to disk eventually without additional VM intevention.
*
* The range is limited to the size of the buffer.
*
* This routine is primarily used by NFS, but is generalized for the
* B_VMIO case.
* Note that while we only really need to clean through to b_bcount, we
* just go ahead and clean through to b_bufsize.
*/
static void
vfs_setdirty(struct buf *bp)
vfs_clean_pages_dirty_buf(struct buf *bp)
{
vm_ooffset_t foff, noff, eoff;
vm_page_t m;
int i;
/*
* Degenerate case - empty buffer
*/
if (bp->b_bufsize == 0)
if ((bp->b_flags & B_VMIO) == 0 || bp->b_bufsize == 0)
return;
if ((bp->b_flags & B_VMIO) == 0)
return;
foff = bp->b_offset;
KASSERT(bp->b_offset != NOOFFSET,
("vfs_clean_pages_dirty_buf: no buffer offset"));
VM_OBJECT_LOCK(bp->b_bufobj->bo_object);
vfs_drain_busy_pages(bp);
vfs_setdirty_locked_object(bp);
for (i = 0; i < bp->b_npages; i++) {
noff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK;
eoff = noff;
if (eoff > bp->b_offset + bp->b_bufsize)
eoff = bp->b_offset + bp->b_bufsize;
m = bp->b_pages[i];
vfs_page_set_validclean(bp, foff, m);
/* vm_page_clear_dirty(m, foff & PAGE_MASK, eoff - foff); */
foff = noff;
}
VM_OBJECT_UNLOCK(bp->b_bufobj->bo_object);
}
@ -3532,6 +3544,31 @@ vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, vm_page_t m)
}
}
/*
* Ensure that all buffer pages are not busied by VPO_BUSY flag. If
* any page is busy, drain the flag.
*/
static void
vfs_drain_busy_pages(struct buf *bp)
{
vm_page_t m;
int i, last_busied;
VM_OBJECT_LOCK_ASSERT(bp->b_bufobj->bo_object, MA_OWNED);
last_busied = 0;
for (i = 0; i < bp->b_npages; i++) {
m = bp->b_pages[i];
if ((m->oflags & VPO_BUSY) != 0) {
for (; last_busied < i; last_busied++)
vm_page_busy(bp->b_pages[last_busied]);
while ((m->oflags & VPO_BUSY) != 0)
vm_page_sleep(m, "vbpage");
}
}
for (i = 0; i < last_busied; i++)
vm_page_wakeup(bp->b_pages[i]);
}
/*
* This routine is called before a device strategy routine.
* It is used to tell the VM system that paging I/O is in
@ -3560,15 +3597,9 @@ vfs_busy_pages(struct buf *bp, int clear_modify)
KASSERT(bp->b_offset != NOOFFSET,
("vfs_busy_pages: no buffer offset"));
VM_OBJECT_LOCK(obj);
vfs_drain_busy_pages(bp);
if (bp->b_bufsize != 0)
vfs_setdirty_locked_object(bp);
retry:
for (i = 0; i < bp->b_npages; i++) {
m = bp->b_pages[i];
if (vm_page_sleep_if_busy(m, FALSE, "vbpage"))
goto retry;
}
bogus = 0;
for (i = 0; i < bp->b_npages; i++) {
m = bp->b_pages[i];
@ -3608,42 +3639,6 @@ vfs_busy_pages(struct buf *bp, int clear_modify)
bp->b_pages, bp->b_npages);
}
/*
* Tell the VM system that the pages associated with this buffer
* are clean. This is used for delayed writes where the data is
* going to go to disk eventually without additional VM intevention.
*
* Note that while we only really need to clean through to b_bcount, we
* just go ahead and clean through to b_bufsize.
*/
static void
vfs_clean_pages(struct buf *bp)
{
int i;
vm_ooffset_t foff, noff, eoff;
vm_page_t m;
if (!(bp->b_flags & B_VMIO))
return;
foff = bp->b_offset;
KASSERT(bp->b_offset != NOOFFSET,
("vfs_clean_pages: no buffer offset"));
VM_OBJECT_LOCK(bp->b_bufobj->bo_object);
for (i = 0; i < bp->b_npages; i++) {
m = bp->b_pages[i];
noff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK;
eoff = noff;
if (eoff > bp->b_offset + bp->b_bufsize)
eoff = bp->b_offset + bp->b_bufsize;
vfs_page_set_validclean(bp, foff, m);
/* vm_page_clear_dirty(m, foff & PAGE_MASK, eoff - foff); */
foff = noff;
}
VM_OBJECT_UNLOCK(bp->b_bufobj->bo_object);
}
/*
* vfs_bio_set_valid:
*