Author: alc
Date: Fri Aug 21 17:00:39 2015
New Revision: 287002
URL: https://svnweb.freebsd.org/changeset/base/287002
Log:
Eliminate pointless assignments to rtvals[] in swap_pager_putpages().
Reviewed by: kib
Sponsored by: EMC / Isilon Storage Division
Modified:
head/sys/vm/swap_pager.c
Modified: head/sys/vm/swap_pager.c
==============================================================================
--- head/sys/vm/swap_pager.c Fri Aug 21 16:05:56 2015 (r287001)
+++ head/sys/vm/swap_pager.c Fri Aug 21 17:00:39 2015 (r287002)
@@ -1404,8 +1404,6 @@ swap_pager_putpages(vm_object_t object,
blk + j
);
vm_page_dirty(mreq);
- rtvals[i+j] = VM_PAGER_OK;
-
mreq->oflags |= VPO_SWAPINPROG;
bp->b_pages[j] = mreq;
}
@@ -1421,6 +1419,16 @@ swap_pager_putpages(vm_object_t object,
PCPU_ADD(cnt.v_swappgsout, bp->b_npages);
/*
+ * We unconditionally set rtvals[] to VM_PAGER_PEND so that we
+ * can call the async completion routine at the end of a
+ * synchronous I/O operation. Otherwise, our caller would
+ * perform duplicate unbusy and wakeup operations on the page
+ * and object, respectively.
+ */
+ for (j = 0; j < n; j++)
+ rtvals[i + j] = VM_PAGER_PEND;
+
+ /*
* asynchronous
*
* NOTE: b_blkno is destroyed by the call to swapdev_strategy
@@ -1429,10 +1437,6 @@ swap_pager_putpages(vm_object_t object,
bp->b_iodone = swp_pager_async_iodone;
BUF_KERNPROC(bp);
swp_pager_strategy(bp);
-
- for (j = 0; j < n; ++j)
- rtvals[i+j] = VM_PAGER_PEND;
- /* restart outter loop */
continue;
}
@@ -1445,14 +1449,10 @@ swap_pager_putpages(vm_object_t object,
swp_pager_strategy(bp);
/*
- * Wait for the sync I/O to complete, then update rtvals.
- * We just set the rtvals[] to VM_PAGER_PEND so we can call
- * our async completion routine at the end, thus avoiding a
- * double-free.
+ * Wait for the sync I/O to complete.
*/
bwait(bp, PVM, "swwrt");
- for (j = 0; j < n; ++j)
- rtvals[i+j] = VM_PAGER_PEND;
+
/*
* Now that we are through with the bp, we can call the
* normal async completion, which frees everything up.
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