Page MenuHomeFreeBSD
Files F131726307

D20001.id56752.diff
No OneTemporary
Actions

D20001.id56752.diff
View Options

Index: sys/vm/swap_pager.c
===================================================================
--- sys/vm/swap_pager.c
+++ sys/vm/swap_pager.c
@@ -407,7 +407,7 @@
* Swap bitmap functions
*/
static void swp_pager_freeswapspace(daddr_t blk, daddr_t npages);
-static daddr_t swp_pager_getswapspace(int npages);
+static daddr_t swp_pager_getswapspace(int *npages, int minpages);
/*
* Metadata functions
@@ -708,9 +708,10 @@
/*
* SWP_PAGER_GETSWAPSPACE() - allocate raw swap space
*
- * Allocate swap for the requested number of pages. The starting
- * swap block number (a page index) is returned or SWAPBLK_NONE
- * if the allocation failed.
+ * Allocate swap for up to the requested number of pages, and at
+ * least a minimum number of pages. The starting swap block number
+ * (a page index) is returned or SWAPBLK_NONE if the allocation
+ * failed.
*
* Also has the side effect of advising that somebody made a mistake
* when they configured swap and didn't configure enough.
@@ -720,40 +721,52 @@
* We allocate in round-robin fashion from the configured devices.
*/
static daddr_t
-swp_pager_getswapspace(int npages)
+swp_pager_getswapspace(int *io_npages, int minpages)
{
daddr_t blk;
struct swdevt *sp;
- int i;
+ int npages;
blk = SWAPBLK_NONE;
+ npages = *io_npages;
mtx_lock(&sw_dev_mtx);
+ if (TAILQ_EMPTY(&swtailq)) {
+ mtx_unlock(&sw_dev_mtx);
+ return (blk);
+ }
sp = swdevhd;
- for (i = 0; i < nswapdev; i++) {
+ while (true) {
if (sp == NULL)
sp = TAILQ_FIRST(&swtailq);
- if (!(sp->sw_flags & SW_CLOSING)) {
+ if ((sp->sw_flags & SW_CLOSING) == 0)
blk = blist_alloc(sp->sw_blist, npages);
- if (blk != SWAPBLK_NONE) {
- blk += sp->sw_first;
- sp->sw_used += npages;
- swap_pager_avail -= npages;
- swp_sizecheck();
- swdevhd = TAILQ_NEXT(sp, sw_list);
- goto done;
- }
+ if (blk != SWAPBLK_NONE) {
+ *io_npages = npages;
+ blk += sp->sw_first;
+ sp->sw_used += npages;
+ swap_pager_avail -= npages;
+ swp_sizecheck();
+ swdevhd = TAILQ_NEXT(sp, sw_list);
+ mtx_unlock(&sw_dev_mtx);
+ return (blk);
}
sp = TAILQ_NEXT(sp, sw_list);
+ if (swdevhd == sp) {
+ if (swap_pager_full != 2) {
+ printf("swp_pager_getswapspace(%d): failed\n",
+ npages);
+ swap_pager_full = 2;
+ swap_pager_almost_full = 1;
+ }
+ sp = swdevhd = NULL;
+ mtx_unlock(&sw_dev_mtx);
+ npages >>= 1;
+ if (npages < minpages)
+ return (blk);
+ mtx_lock(&sw_dev_mtx);
+
+ }
}
- if (swap_pager_full != 2) {
- printf("swap_pager_getswapspace(%d): failed\n", npages);
- swap_pager_full = 2;
- swap_pager_almost_full = 1;
- }
- swdevhd = NULL;
-done:
- mtx_unlock(&sw_dev_mtx);
- return (blk);
}
static bool
@@ -886,35 +899,30 @@
int
swap_pager_reserve(vm_object_t object, vm_pindex_t start, vm_size_t size)
{
- int n = 0;
- daddr_t blk = SWAPBLK_NONE;
+ int i, n;
+ daddr_t blk;
vm_pindex_t beg = start; /* save start index */
daddr_t addr, n_free, s_free;
swp_pager_init_freerange(&s_free, &n_free);
VM_OBJECT_WLOCK(object);
- while (size) {
- if (n == 0) {
- n = BLIST_MAX_ALLOC;
- while ((blk = swp_pager_getswapspace(n)) == SWAPBLK_NONE) {
- n >>= 1;
- if (n == 0) {
- swp_pager_meta_free(object, beg, start - beg);
- VM_OBJECT_WUNLOCK(object);
- return (-1);
- }
- }
+ while (beg + size > start) {
+ n = min(BLIST_MAX_ALLOC, beg + size - start);
+ blk = swp_pager_getswapspace(&n, 1);
+ if (blk == SWAPBLK_NONE) {
+ swp_pager_meta_free(object, beg, start - beg);
+ VM_OBJECT_WUNLOCK(object);
+ return (-1);
}
- addr = swp_pager_meta_build(object, start, blk);
- if (addr != SWAPBLK_NONE)
+ for (i = 0; i < n; ++i) {
+ addr = swp_pager_meta_build(object, start + i, blk + i);
+ if (addr == SWAPBLK_NONE)
+ continue;
swp_pager_update_freerange(&s_free, &n_free, addr);
- --size;
- ++start;
- ++blk;
- --n;
+ }
+ start += n;
}
swp_pager_freeswapspace(s_free, n_free);
- swp_pager_meta_free(object, start, n);
VM_OBJECT_WUNLOCK(object);
return (0);
}
@@ -1384,18 +1392,8 @@
n = min(BLIST_MAX_ALLOC, count - i);
n = min(n, nsw_cluster_max);
- /*
- * Get biggest block of swap we can. If we fail, fall
- * back and try to allocate a smaller block. Don't go
- * overboard trying to allocate space if it would overly
- * fragment swap.
- */
- while (
- (blk = swp_pager_getswapspace(n)) == SWAPBLK_NONE &&
- n > 4
- ) {
- n >>= 1;
- }
+ /* Get a block of swap of size up to size n. */
+ blk = swp_pager_getswapspace(&n, 2);
if (blk == SWAPBLK_NONE) {
for (j = 0; j < n; ++j)
rtvals[i+j] = VM_PAGER_FAIL;

File Metadata

Mime Type
text/plain
Expires
Sat, Oct 11, 4:32 PM (15 h, 31 m)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
23584228
Default Alt Text
D20001.id56752.diff (4 KB)

Event Timeline