Author: kib
Date: Sat Oct 24 21:59:22 2015
New Revision: 289895
URL: https://svnweb.freebsd.org/changeset/base/289895
Log:
Reduce the amount of calls to VOP_BMAP() made from the local vnode
pager. It is enough to execute VOP_BMAP() once to obtain both the
disk block address for the requested page, and the before/after limits
for the contiguous run. The clipping of the vm_page_t array passed to
the vnode_pager_generic_getpages() and the disk address for the first
page in the clipped array can be deduced from the call results.
While there, remove some noise (like if (1) {...}) and adjust nearby
code.
Reviewed by: alc
Discussed with: glebius
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
Modified:
head/sys/vm/vnode_pager.c
Modified: head/sys/vm/vnode_pager.c
==============================================================================
--- head/sys/vm/vnode_pager.c Sat Oct 24 21:37:47 2015 (r289894)
+++ head/sys/vm/vnode_pager.c Sat Oct 24 21:59:22 2015 (r289895)
@@ -767,26 +767,21 @@ vnode_pager_generic_getpages(struct vnod
int reqpage, vop_getpages_iodone_t iodone, void *arg)
{
vm_object_t object;
- off_t foff;
- int i, j, size, bsize, first, *freecnt;
- daddr_t firstaddr, reqblock;
struct bufobj *bo;
- int runpg;
- int runend;
struct buf *bp;
- int count;
- int error;
-
- object = vp->v_object;
- count = bytecount / PAGE_SIZE;
+ daddr_t firstaddr, reqblock;
+ off_t foff;
+ int pbefore, pafter, i, size, bsize, first, last, *freecnt;
+ int count, error, before, after, secmask;
KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
("vnode_pager_generic_getpages does not support devices"));
if (vp->v_iflag & VI_DOOMED)
- return VM_PAGER_BAD;
+ return (VM_PAGER_BAD);
+ object = vp->v_object;
+ count = bytecount / PAGE_SIZE;
bsize = vp->v_mount->mnt_stat.f_iosize;
- foff = IDX_TO_OFF(m[reqpage]->pindex);
/*
* Synchronous and asynchronous paging operations use different
@@ -805,7 +800,8 @@ vnode_pager_generic_getpages(struct vnod
* If the file system doesn't support VOP_BMAP, use old way of
* getting pages via VOP_READ.
*/
- error = VOP_BMAP(vp, foff / bsize, &bo, &reqblock, NULL, NULL);
+ error = VOP_BMAP(vp, IDX_TO_OFF(m[reqpage]->pindex) / bsize, &bo,
+ &reqblock, &after, &before);
if (error == EOPNOTSUPP) {
relpbuf(bp, freecnt);
VM_OBJECT_WLOCK(object);
@@ -836,7 +832,7 @@ vnode_pager_generic_getpages(struct vnod
vm_pager_free_nonreq(object, m, reqpage, count, FALSE);
PCPU_INC(cnt.v_vnodein);
PCPU_INC(cnt.v_vnodepgsin);
- return vnode_pager_input_smlfs(object, m[reqpage]);
+ return (vnode_pager_input_smlfs(object, m[reqpage]));
}
/*
@@ -870,75 +866,39 @@ vnode_pager_generic_getpages(struct vnod
VM_OBJECT_WUNLOCK(object);
}
- /*
- * here on direct device I/O
- */
- firstaddr = -1;
-
- /*
- * calculate the run that includes the required page
- */
- 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);
- /* The requested page may be out of range. */
- vm_pager_free_nonreq(object, m + i, reqpage - i,
- count - i, FALSE);
- return (VM_PAGER_ERROR);
- }
- if (firstaddr == -1) {
- VM_OBJECT_WLOCK(object);
- if (i == reqpage && foff <
object->un_pager.vnp.vnp_size) {
- panic("vnode_pager_getpages: unexpected missing
page: firstaddr: %jd, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx",
- (intmax_t)firstaddr, (uintmax_t)(foff >>
32),
- (uintmax_t)foff,
- (uintmax_t)
- (object->un_pager.vnp.vnp_size >> 32),
- (uintmax_t)object->un_pager.vnp.vnp_size);
- }
+ pbefore = (daddr_t)before * bsize / PAGE_SIZE;
+ pafter = (daddr_t)after * bsize / PAGE_SIZE;
+ first = reqpage < pbefore ? 0 : reqpage - pbefore;
+ last = reqpage + pafter >= count ? count - 1 : reqpage + pafter;
+ if (first > 0 || last + 1 < count) {
+ VM_OBJECT_WLOCK(object);
+ for (i = 0; i < first; i++) {
vm_page_lock(m[i]);
vm_page_free(m[i]);
vm_page_unlock(m[i]);
- VM_OBJECT_WUNLOCK(object);
- runend = i + 1;
- first = runend;
- continue;
}
- runend = i + runpg;
- if (runend <= reqpage) {
- VM_OBJECT_WLOCK(object);
- for (j = i; j < runend; j++) {
- vm_page_lock(m[j]);
- vm_page_free(m[j]);
- vm_page_unlock(m[j]);
- }
- VM_OBJECT_WUNLOCK(object);
- } else {
- if (runpg < (count - first)) {
- VM_OBJECT_WLOCK(object);
- for (i = first + runpg; i < count; i++) {
- vm_page_lock(m[i]);
- vm_page_free(m[i]);
- vm_page_unlock(m[i]);
- }
- VM_OBJECT_WUNLOCK(object);
- count = first + runpg;
- }
- break;
+ for (i = last + 1; i < count; i++) {
+ vm_page_lock(m[i]);
+ vm_page_free(m[i]);
+ vm_page_unlock(m[i]);
}
- first = runend;
+ VM_OBJECT_WUNLOCK(object);
}
/*
- * the first and last page have been calculated now, move input pages
- * to be zero based...
+ * here on direct device I/O
*/
- if (first != 0) {
- m += first;
- count -= first;
- reqpage -= first;
- }
+ firstaddr = reqblock;
+ firstaddr += (IDX_TO_OFF(m[reqpage]->pindex) % bsize) / DEV_BSIZE;
+ firstaddr -= IDX_TO_OFF(reqpage - first) / DEV_BSIZE;
+
+ /*
+ * The first and last page have been calculated now, move
+ * input pages to be zero based, and adjust the count.
+ */
+ m += first;
+ reqpage -= first;
+ count = last - first + 1;
/*
* calculate the file virtual address for the transfer
@@ -957,13 +917,11 @@ vnode_pager_generic_getpages(struct vnod
/*
* round up physical size for real devices.
*/
- if (1) {
- int secmask = bo->bo_bsize - 1;
- KASSERT(secmask < PAGE_SIZE && secmask > 0,
- ("vnode_pager_generic_getpages: sector size %d too large",
- secmask + 1));
- size = (size + secmask) & ~secmask;
- }
+ secmask = bo->bo_bsize - 1;
+ KASSERT(secmask < PAGE_SIZE && secmask > 0,
+ ("vnode_pager_generic_getpages: sector size %d too large",
+ secmask + 1));
+ size = (size + secmask) & ~secmask;
/*
* and map the pages to be read into the kva, if the filesystem
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