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Index: sys/kern/subr_blist.c
===================================================================
--- sys/kern/subr_blist.c
+++ sys/kern/subr_blist.c
@@ -295,7 +295,7 @@
* not be allocated.
*/
daddr_t
-blist_alloc(blist_t bl, int *count, int maxcount)
+blist_alloc(blist_t bl, daddr_t *io_cursor, int *count, int maxcount)
{
daddr_t blk, cursor;
@@ -310,14 +310,14 @@
* non-zero. When the cursor is zero, an allocation failure will
* stop further iterations.
*/
- for (cursor = bl->bl_cursor;; cursor = 0) {
+ for (cursor = *io_cursor;; cursor = 0) {
blk = blst_meta_alloc(bl->bl_root, cursor, count, maxcount,
bl->bl_radix);
if (blk != SWAPBLK_NONE) {
bl->bl_avail -= *count;
- bl->bl_cursor = blk + *count;
- if (bl->bl_cursor == bl->bl_blocks)
- bl->bl_cursor = 0;
+ *io_cursor = blk + *count;
+ if (*io_cursor == bl->bl_blocks)
+ *io_cursor = 0;
return (blk);
}
if (cursor == 0)
@@ -404,8 +404,7 @@
void
blist_print(blist_t bl)
{
- printf("BLIST avail = %jd, cursor = %08jx {\n",
- (uintmax_t)bl->bl_avail, (uintmax_t)bl->bl_cursor);
+ printf("BLIST avail = %jd {\n", (uintmax_t)bl->bl_avail);
if (bl->bl_root->bm_bitmap != 0)
blst_radix_print(bl->bl_root, 0, bl->bl_radix, 4);
Index: sys/sys/blist.h
===================================================================
--- sys/sys/blist.h
+++ sys/sys/blist.h
@@ -81,7 +81,6 @@
daddr_t bl_blocks; /* area of coverage */
daddr_t bl_avail; /* # available blocks */
u_daddr_t bl_radix; /* coverage radix */
- daddr_t bl_cursor; /* next-fit search starts at */
blmeta_t bl_root[1]; /* root of radix tree */
} *blist_t;
@@ -92,7 +91,7 @@
struct sbuf;
-daddr_t blist_alloc(blist_t blist, int *count, int maxcount);
+daddr_t blist_alloc(blist_t blist, daddr_t *cursor, int *count, int maxcount);
daddr_t blist_avail(blist_t blist);
blist_t blist_create(daddr_t blocks, int flags);
void blist_destroy(blist_t blist);
Index: sys/vm/swap_pager.h
===================================================================
--- sys/vm/swap_pager.h
+++ sys/vm/swap_pager.h
@@ -65,6 +65,8 @@
swblk_t sw_first;
swblk_t sw_end;
struct blist *sw_blist;
+ daddr_t sw_cursor; /* next-fit search starts at */
+ daddr_t sw_trimmer; /* where to look for free space to trim */
TAILQ_ENTRY(swdevt) sw_list;
sw_strategy_t *sw_strategy;
sw_close_t *sw_close;
Index: sys/vm/swap_pager.c
===================================================================
--- sys/vm/swap_pager.c
+++ sys/vm/swap_pager.c
@@ -702,6 +702,85 @@
object->type = OBJT_DEAD;
}
+static void
+swp_pager_async_trimdone(struct buf *bp)
+{
+ struct swdevt *sp;
+ daddr_t blk;
+ int npages;
+
+ sp = (struct swdevt *)bp->b_fsprivate1;
+ blk = bp->b_blkno;
+ npages = bp->b_npages;
+ uma_zfree(swwbuf_zone, bp);
+
+ mtx_lock(&swbuf_mtx);
+ if (++nsw_wcount_async == 1)
+ wakeup(&nsw_wcount_async);
+ mtx_unlock(&swbuf_mtx);
+
+ mtx_lock(&sw_dev_mtx);
+ blk -= sp->sw_first;
+ blist_free(sp->sw_blist, blk, npages);
+ mtx_unlock(&sw_dev_mtx);
+}
+
+static struct buf *
+swapdev_trim(struct swdevt *sp)
+{
+ struct buf *bp;
+ daddr_t blk;
+ u_long nblks;
+ int npages, mpages;
+
+ /* Quit if the cursor is too far behind the trimmer. */
+ mtx_lock(&sw_dev_mtx);
+ nblks = sp->sw_nblks;
+ blk = sp->sw_trimmer;
+ if ((blk + nblks - sp->sw_cursor) % nblks > nblks / 5) {
+ mtx_unlock(&sw_dev_mtx);
+ return (NULL);
+ }
+
+ /* Grab a lot of free space allocated long ago. */
+ npages = 1;
+ mpages = 10000;
+ blk = blist_alloc(sp->sw_blist, &sp->sw_trimmer, &npages, mpages);
+
+ /* Quit if there's nothing free between the trimmer and cursor. */
+ if (blk == SWAPBLK_NONE) {
+ mtx_unlock(&sw_dev_mtx);
+ return (NULL);
+ }
+ if ((blk + nblks - sp->sw_cursor) % nblks > nblks / 5) {
+ /* The trim allocation jumped the cursor. Bail out. */
+ blist_free(sp->sw_blist, blk, npages);
+ mtx_unlock(&sw_dev_mtx);
+ return (NULL);
+ }
+ blk += sp->sw_first;
+ mtx_unlock(&sw_dev_mtx);
+ mtx_lock(&swbuf_mtx);
+ while (nsw_wcount_async == 0)
+ msleep(&nsw_wcount_async, &swbuf_mtx, PVM,
+ "swbufa", 0);
+ nsw_wcount_async--;
+ mtx_unlock(&swbuf_mtx);
+ bp = uma_zalloc(swwbuf_zone, M_WAITOK);
+ bp->b_flags = B_ASYNC;
+ bp->b_iocmd = BIO_DELETE;
+ bp->b_rcred = crhold(thread0.td_ucred);
+ bp->b_wcred = crhold(thread0.td_ucred);
+ bp->b_bcount = PAGE_SIZE * npages;
+ bp->b_bufsize = PAGE_SIZE * npages;
+ bp->b_blkno = blk;
+ bp->b_npages = npages;
+ bp->b_iodone = swp_pager_async_trimdone;
+ bp->b_fsprivate1 = sp;
+ BUF_KERNPROC(bp);
+ return (bp);
+}
+
/************************************************************************
* SWAP PAGER BITMAP ROUTINES *
************************************************************************/
@@ -726,6 +805,7 @@
{
daddr_t blk;
struct swdevt *sp;
+ struct buf *bp;
int mpages, npages;
blk = SWAPBLK_NONE;
@@ -737,7 +817,8 @@
if (sp == NULL)
sp = TAILQ_FIRST(&swtailq);
if ((sp->sw_flags & SW_CLOSING) == 0)
- blk = blist_alloc(sp->sw_blist, &npages, mpages);
+ blk = blist_alloc(sp->sw_blist, &sp->sw_cursor,
+ &npages, mpages);
if (blk != SWAPBLK_NONE)
break;
sp = TAILQ_NEXT(sp, sw_list);
@@ -765,6 +846,13 @@
swdevhd = NULL;
}
mtx_unlock(&sw_dev_mtx);
+
+ if (blk != SWAPBLK_NONE) {
+ bp = swapdev_trim(sp);
+ if (bp != NULL)
+ swp_pager_strategy(bp);
+ }
+
return (blk);
}
@@ -899,18 +987,31 @@
swap_pager_reserve(vm_object_t object, vm_pindex_t start, vm_size_t size)
{
daddr_t addr, blk, n_free, s_free;
- int i, j, n;
+ int i, j, k, n;
+ struct {
+ daddr_t blk;
+ int nblks;
+ } mem[size];
+ for (i = k = 0; i < size; i += n, k++) {
+ n = size - i;
+ blk = swp_pager_getswapspace(&n, 1);
+ if (blk == SWAPBLK_NONE)
+ break;
+ mem[k].blk = blk;
+ mem[k].nblks = n;
+ }
+ if (i < size) {
+ while (k-- > 0)
+ swp_pager_freeswapspace(mem[k].blk, mem[k].nblks);
+ return (-1);
+ }
+
swp_pager_init_freerange(&s_free, &n_free);
VM_OBJECT_WLOCK(object);
- for (i = 0; i < size; i += n) {
- n = size - i;
- blk = swp_pager_getswapspace(&n, 1);
- if (blk == SWAPBLK_NONE) {
- swp_pager_meta_free(object, start, i);
- VM_OBJECT_WUNLOCK(object);
- return (-1);
- }
+ for (i = k = 0; i < size; i += n, k++) {
+ blk = mem[k].blk;
+ n = mem[k].blks;
for (j = 0; j < n; ++j) {
addr = swp_pager_meta_build(object,
start + i + j, blk + j);
@@ -2310,6 +2411,8 @@
sp->sw_flags = flags;
sp->sw_blist = blist_create(nblks, M_WAITOK);
+ sp->sw_cursor = 0;
+ sp->sw_trimmer = 0;
/*
* Do not free the first two block in order to avoid overwriting
* any bsd label at the front of the partition

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