svn commit: r349767 - head/sys/vm
Doug Moore
dougm at FreeBSD.org
Fri Jul 5 16:49:36 UTC 2019
Author: dougm
Date: Fri Jul 5 16:49:34 2019
New Revision: 349767
URL: https://svnweb.freebsd.org/changeset/base/349767
Log:
Based on work posted at https://reviews.freebsd.org/D13484, change
swap_pager_swapoff_object and swp_pager_force_pagein so that they can
page in multiple pages at a time to a swap device, rather than doing
one I/O operation for each page.
Tested by: pho
Submitted by: ota_j.email.ne.jp (Yoshihiro Ota)
Reviewed by: alc, markj, kib
Approved by: kib, markj (mentors)
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D20635
Modified:
head/sys/vm/swap_pager.c
Modified: head/sys/vm/swap_pager.c
==============================================================================
--- head/sys/vm/swap_pager.c Fri Jul 5 16:43:41 2019 (r349766)
+++ head/sys/vm/swap_pager.c Fri Jul 5 16:49:34 2019 (r349767)
@@ -1662,6 +1662,7 @@ swp_pager_force_dirty(vm_page_t m)
vm_page_unlock(m);
#endif
vm_page_xunbusy(m);
+ swap_pager_unswapped(m);
}
static void
@@ -1673,69 +1674,116 @@ swp_pager_force_launder(vm_page_t m)
vm_page_launder(m);
vm_page_unlock(m);
vm_page_xunbusy(m);
+ swap_pager_unswapped(m);
}
/*
- * SWP_PAGER_FORCE_PAGEIN() - force a swap block to be paged in
+ * SWP_PAGER_FORCE_PAGEIN() - force swap blocks to be paged in
*
- * This routine dissociates the page at the given index within an object
- * from its backing store, paging it in if it does not reside in memory.
- * If the page is paged in, it is marked dirty and placed in the laundry
- * queue. The page is marked dirty because it no longer has backing
- * store. It is placed in the laundry queue because it has not been
- * accessed recently. Otherwise, it would already reside in memory.
- *
- * We also attempt to swap in all other pages in the swap block.
- * However, we only guarantee that the one at the specified index is
- * paged in.
- *
- * XXX - The code to page the whole block in doesn't work, so we
- * revert to the one-by-one behavior for now. Sigh.
+ * This routine dissociates pages starting at the given index within an
+ * object from their backing store, paging them in if they do not reside
+ * in memory. Pages that are paged in are marked dirty and placed in the
+ * laundry queue. Pages are marked dirty because they no longer have
+ * backing store. They are placed in the laundry queue because they have
+ * not been accessed recently. Otherwise, they would already reside in
+ * memory.
*/
static void
-swp_pager_force_pagein(vm_object_t object, vm_pindex_t pindex)
+swp_pager_force_pagein(vm_object_t object, vm_pindex_t pindex, int npages)
{
- vm_page_t m;
+ vm_page_t ma[npages];
+ int i, j;
- vm_object_pip_add(object, 1);
- m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL);
- if (m->valid == VM_PAGE_BITS_ALL) {
- vm_object_pip_wakeup(object);
- swp_pager_force_dirty(m);
- vm_pager_page_unswapped(m);
- return;
+ KASSERT(npages > 0, ("%s: No pages", __func__));
+ KASSERT(npages <= MAXPHYS / PAGE_SIZE,
+ ("%s: Too many pages: %d", __func__, npages));
+ vm_object_pip_add(object, npages);
+ vm_page_grab_pages(object, pindex, VM_ALLOC_NORMAL, ma, npages);
+ for (i = j = 0;; i++) {
+ /* Count nonresident pages, to page-in all at once. */
+ if (i < npages && ma[i]->valid != VM_PAGE_BITS_ALL)
+ continue;
+ if (j < i) {
+ /* Page-in nonresident pages. Mark for laundering. */
+ if (swap_pager_getpages(object, &ma[j], i - j, NULL,
+ NULL) != VM_PAGER_OK)
+ panic("%s: read from swap failed", __func__);
+ do {
+ swp_pager_force_launder(ma[j]);
+ } while (++j < i);
+ }
+ if (i == npages)
+ break;
+ /* Mark dirty a resident page. */
+ swp_pager_force_dirty(ma[j++]);
}
-
- if (swap_pager_getpages(object, &m, 1, NULL, NULL) != VM_PAGER_OK)
- panic("swap_pager_force_pagein: read from swap failed");/*XXX*/
- vm_object_pip_wakeup(object);
- swp_pager_force_launder(m);
- vm_pager_page_unswapped(m);
+ vm_object_pip_wakeupn(object, npages);
}
/*
* swap_pager_swapoff_object:
*
* Page in all of the pages that have been paged out for an object
- * from a given swap device.
+ * to a swap device.
*/
static void
swap_pager_swapoff_object(struct swdevt *sp, vm_object_t object)
{
struct swblk *sb;
- vm_pindex_t pi;
+ vm_pindex_t pi, s_pindex;
+ daddr_t blk, n_blks, s_blk;
int i;
+ n_blks = 0;
for (pi = 0; (sb = SWAP_PCTRIE_LOOKUP_GE(
&object->un_pager.swp.swp_blks, pi)) != NULL; ) {
- pi = sb->p + SWAP_META_PAGES;
for (i = 0; i < SWAP_META_PAGES; i++) {
- if (sb->d[i] == SWAPBLK_NONE)
+ blk = sb->d[i];
+ if (!swp_pager_isondev(blk, sp))
+ blk = SWAPBLK_NONE;
+
+ /*
+ * If there are no blocks/pages accumulated, start a new
+ * accumulation here.
+ */
+ if (n_blks == 0) {
+ if (blk != SWAPBLK_NONE) {
+ s_blk = blk;
+ s_pindex = sb->p + i;
+ n_blks = 1;
+ }
continue;
- if (swp_pager_isondev(sb->d[i], sp))
- swp_pager_force_pagein(object, sb->p + i);
+ }
+
+ /*
+ * If the accumulation can be extended without breaking
+ * the sequence of consecutive blocks and pages that
+ * swp_pager_force_pagein() depends on, do so.
+ */
+ if (n_blks < MAXPHYS / PAGE_SIZE &&
+ s_blk + n_blks == blk &&
+ s_pindex + n_blks == sb->p + i) {
+ ++n_blks;
+ continue;
+ }
+
+ /*
+ * The sequence of consecutive blocks and pages cannot
+ * be extended, so page them all in here. Then,
+ * because doing so involves releasing and reacquiring
+ * a lock that protects the swap block pctrie, do not
+ * rely on the current swap block. Break this loop and
+ * re-fetch the same pindex from the pctrie again.
+ */
+ swp_pager_force_pagein(object, s_pindex, n_blks);
+ n_blks = 0;
+ break;
}
+ if (i == SWAP_META_PAGES)
+ pi = sb->p + SWAP_META_PAGES;
}
+ if (n_blks > 0)
+ swp_pager_force_pagein(object, s_pindex, n_blks);
}
/*
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