Author: glebius
Date: Fri Mar 6 14:15:30 2015
New Revision: 279688
URL: https://svnweb.freebsd.org/changeset/base/279688
Log:
- In vnode_pager_generic_getpages() use different free counters for
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
Modified:
head/sys/sys/buf.h
head/sys/vm/vm_pager.c
head/sys/vm/vnode_pager.c
Modified: head/sys/sys/buf.h
==============================================================================
--- head/sys/sys/buf.h Fri Mar 6 11:27:58 2015 (r279687)
+++ head/sys/sys/buf.h Fri Mar 6 14:15:30 2015 (r279688)
@@ -475,6 +475,8 @@ extern struct buf *swbuf; /* Swap I/O b
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 *);
Modified: head/sys/vm/vm_pager.c
==============================================================================
--- head/sys/vm/vm_pager.c Fri Mar 6 11:27:58 2015 (r279687)
+++ head/sys/vm/vm_pager.c Fri Mar 6 14:15:30 2015 (r279688)
@@ -215,6 +215,7 @@ vm_pager_bufferinit()
cluster_pbuf_freecnt = nswbuf / 2;
vnode_pbuf_freecnt = nswbuf / 2 + 1;
+ vnode_async_pbuf_freecnt = nswbuf / 2;
}
/*
Modified: head/sys/vm/vnode_pager.c
==============================================================================
--- head/sys/vm/vnode_pager.c Fri Mar 6 11:27:58 2015 (r279687)
+++ head/sys/vm/vnode_pager.c Fri Mar 6 14:15:30 2015 (r279688)
@@ -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 vnod
{
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 vnod
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 vnod
*/
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 vnod
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 vnod
*/
} 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 vnod
* 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 vnod
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 vnod
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(
bp->b_pages[i] = NULL;
bp->b_vp = NULL;
pbrelbo(bp);
- relpbuf(bp, &vnode_pbuf_freecnt);
+ relpbuf(bp, &vnode_async_pbuf_freecnt);
}
static int
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