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- In vnode_pager_generic_getpages() use different free counters for

Browse Source 
synchronous and asynchronous requests.  The latter can saturate the
  I/O and we do not want them to affect regular paging.
- Allocate the pbuf at the very beginning of the function, so that
  if we are low on certain kind of pbufs don't even proceed to BMAP,
  but sleep.

Reviewed by:	kib
Sponsored by:	Nginx, Inc.
Sponsored by:	Netflix
This commit is contained in:
Gleb Smirnoff 2015-03-06 14:15:30 +00:00
parent fd8dd3a6d7
commit 73e9030e61
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=279688
3 changed files with 16 additions and 4 deletions
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2
sys/sys/buf.h
View File

@ -475,6 +475,8 @@ extern struct buf *swbuf; /* Swap I/O buffer headers. */
extern int nswbuf; /* Number of swap I/O buffer headers. */
extern int cluster_pbuf_freecnt; /* Number of pbufs for clusters */
extern int vnode_pbuf_freecnt; /* Number of pbufs for vnode pager */
extern int vnode_async_pbuf_freecnt; /* Number of pbufs for vnode pager,
asynchronous reads */
extern caddr_t unmapped_buf;
void runningbufwakeup(struct buf *);

1
sys/vm/vm_pager.c
View File

@ -215,6 +215,7 @@ vm_pager_bufferinit()
cluster_pbuf_freecnt = nswbuf / 2;
vnode_pbuf_freecnt = nswbuf / 2 + 1;
vnode_async_pbuf_freecnt = nswbuf / 2;
}
/*

17
sys/vm/vnode_pager.c
View File

@ -104,6 +104,7 @@ struct pagerops vnodepagerops = {
};
int vnode_pbuf_freecnt;
int vnode_async_pbuf_freecnt;
/* Create the VM system backing object for this vnode */
int
@ -751,7 +752,7 @@ vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int bytecount,
{
vm_object_t object;
off_t foff;
int i, j, size, bsize, first;
int i, j, size, bsize, first, *freecnt;
daddr_t firstaddr, reqblock;
struct bufobj *bo;
int runpg;
@ -771,6 +772,10 @@ vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int bytecount,
bsize = vp->v_mount->mnt_stat.f_iosize;
foff = IDX_TO_OFF(m[reqpage]->pindex);
freecnt = iodone != NULL ?
&vnode_async_pbuf_freecnt : &vnode_pbuf_freecnt;
bp = getpbuf(freecnt);
/*
* Get the underlying device blocks for the file with VOP_BMAP().
* If the file system doesn't support VOP_BMAP, use old way of
@ -778,8 +783,8 @@ vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int bytecount,
*/
error = VOP_BMAP(vp, foff / bsize, &bo, &reqblock, NULL, NULL);
if (error == EOPNOTSUPP) {
relpbuf(bp, freecnt);
VM_OBJECT_WLOCK(object);
for (i = 0; i < count; i++)
if (i != reqpage) {
vm_page_lock(m[i]);
@ -792,6 +797,7 @@ vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int bytecount,
VM_OBJECT_WUNLOCK(object);
return (error);
} else if (error != 0) {
relpbuf(bp, freecnt);
vm_pager_free_nonreq(object, m, reqpage, count);
return (VM_PAGER_ERROR);
@ -802,6 +808,7 @@ vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int bytecount,
*/
} else if ((PAGE_SIZE / bsize) > 1 &&
(vp->v_mount->mnt_stat.f_type != nfs_mount_type)) {
relpbuf(bp, freecnt);
vm_pager_free_nonreq(object, m, reqpage, count);
PCPU_INC(cnt.v_vnodein);
PCPU_INC(cnt.v_vnodepgsin);
@ -820,9 +827,11 @@ vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int bytecount,
* media.
*/
if (m[reqpage]->valid == VM_PAGE_BITS_ALL) {
relpbuf(bp, freecnt);
vm_pager_free_nonreq(object, m, reqpage, count);
return (VM_PAGER_OK);
} else if (reqblock == -1) {
relpbuf(bp, freecnt);
pmap_zero_page(m[reqpage]);
KASSERT(m[reqpage]->dirty == 0,
("vnode_pager_generic_getpages: page %p is dirty", m));
@ -853,6 +862,7 @@ vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int bytecount,
for (first = 0, i = 0; i < count; i = runend) {
if (vnode_pager_addr(vp, IDX_TO_OFF(m[i]->pindex), &firstaddr,
&runpg) != 0) {
relpbuf(bp, freecnt);
VM_OBJECT_WLOCK(object);
for (; i < count; i++)
if (i != reqpage) {
@ -941,7 +951,6 @@ vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int bytecount,
size = (size + secmask) & ~secmask;
}
bp = getpbuf(&vnode_pbuf_freecnt);
bp->b_kvaalloc = bp->b_data;
/*
@ -1016,7 +1025,7 @@ vnode_pager_generic_getpages_done_async(struct buf *bp)
bp->b_pages[i] = NULL;
bp->b_vp = NULL;
pbrelbo(bp);
relpbuf(bp, &vnode_pbuf_freecnt);
relpbuf(bp, &vnode_async_pbuf_freecnt);
}
static int