svn commit: r335674 - head/sys/vm
Alan Cox
alc at FreeBSD.org
Tue Jun 26 18:29:58 UTC 2018
Author: alc
Date: Tue Jun 26 18:29:56 2018
New Revision: 335674
URL: https://svnweb.freebsd.org/changeset/base/335674
Log:
Update the physical page selection strategy used by vm_page_import() so
that it does not cause rapid fragmentation of the free physical memory.
Reviewed by: jeff, markj (an earlier version)
Differential Revision: https://reviews.freebsd.org/D15976
Modified:
head/sys/vm/vm_page.c
head/sys/vm/vm_phys.c
head/sys/vm/vm_phys.h
Modified: head/sys/vm/vm_page.c
==============================================================================
--- head/sys/vm/vm_page.c Tue Jun 26 18:07:16 2018 (r335673)
+++ head/sys/vm/vm_page.c Tue Jun 26 18:29:56 2018 (r335674)
@@ -2235,24 +2235,16 @@ static int
vm_page_import(void *arg, void **store, int cnt, int domain, int flags)
{
struct vm_domain *vmd;
- vm_page_t m;
- int i, j, n;
+ int i;
vmd = arg;
/* Only import if we can bring in a full bucket. */
if (cnt == 1 || !vm_domain_allocate(vmd, VM_ALLOC_NORMAL, cnt))
return (0);
domain = vmd->vmd_domain;
- n = 64; /* Starting stride, arbitrary. */
vm_domain_free_lock(vmd);
- for (i = 0; i < cnt; i+=n) {
- n = vm_phys_alloc_npages(domain, VM_FREELIST_DEFAULT, &m,
- MIN(n, cnt-i));
- if (n == 0)
- break;
- for (j = 0; j < n; j++)
- store[i+j] = m++;
- }
+ i = vm_phys_alloc_npages(domain, VM_FREEPOOL_DEFAULT, cnt,
+ (vm_page_t *)store);
vm_domain_free_unlock(vmd);
if (cnt != i)
vm_domain_freecnt_inc(vmd, cnt - i);
Modified: head/sys/vm/vm_phys.c
==============================================================================
--- head/sys/vm/vm_phys.c Tue Jun 26 18:07:16 2018 (r335673)
+++ head/sys/vm/vm_phys.c Tue Jun 26 18:29:56 2018 (r335674)
@@ -605,6 +605,76 @@ vm_phys_split_pages(vm_page_t m, int oind, struct vm_f
}
/*
+ * Tries to allocate the specified number of pages from the specified pool
+ * within the specified domain. Returns the actual number of allocated pages
+ * and a pointer to each page through the array ma[].
+ *
+ * The returned pages may not be physically contiguous. However, in contrast to
+ * performing multiple, back-to-back calls to vm_phys_alloc_pages(..., 0),
+ * calling this function once to allocate the desired number of pages will avoid
+ * wasted time in vm_phys_split_pages().
+ *
+ * The free page queues for the specified domain must be locked.
+ */
+int
+vm_phys_alloc_npages(int domain, int pool, int npages, vm_page_t ma[])
+{
+ struct vm_freelist *alt, *fl;
+ vm_page_t m;
+ int avail, end, flind, freelist, i, need, oind, pind;
+
+ KASSERT(domain >= 0 && domain < vm_ndomains,
+ ("vm_phys_alloc_npages: domain %d is out of range", domain));
+ KASSERT(pool < VM_NFREEPOOL,
+ ("vm_phys_alloc_npages: pool %d is out of range", pool));
+ KASSERT(npages <= 1 << (VM_NFREEORDER - 1),
+ ("vm_phys_alloc_npages: npages %d is out of range", npages));
+ vm_domain_free_assert_locked(VM_DOMAIN(domain));
+ i = 0;
+ for (freelist = 0; freelist < VM_NFREELIST; freelist++) {
+ flind = vm_freelist_to_flind[freelist];
+ if (flind < 0)
+ continue;
+ fl = vm_phys_free_queues[domain][flind][pool];
+ for (oind = 0; oind < VM_NFREEORDER; oind++) {
+ while ((m = TAILQ_FIRST(&fl[oind].pl)) != NULL) {
+ vm_freelist_rem(fl, m, oind);
+ avail = 1 << oind;
+ need = imin(npages - i, avail);
+ for (end = i + need; i < end;)
+ ma[i++] = m++;
+ if (need < avail) {
+ vm_phys_free_contig(m, avail - need);
+ return (npages);
+ } else if (i == npages)
+ return (npages);
+ }
+ }
+ for (oind = VM_NFREEORDER - 1; oind >= 0; oind--) {
+ for (pind = 0; pind < VM_NFREEPOOL; pind++) {
+ alt = vm_phys_free_queues[domain][flind][pind];
+ while ((m = TAILQ_FIRST(&alt[oind].pl)) !=
+ NULL) {
+ vm_freelist_rem(alt, m, oind);
+ vm_phys_set_pool(pool, m, oind);
+ avail = 1 << oind;
+ need = imin(npages - i, avail);
+ for (end = i + need; i < end;)
+ ma[i++] = m++;
+ if (need < avail) {
+ vm_phys_free_contig(m, avail -
+ need);
+ return (npages);
+ } else if (i == npages)
+ return (npages);
+ }
+ }
+ }
+ }
+ return (i);
+}
+
+/*
* Allocate a contiguous, power of two-sized set of physical pages
* from the free lists.
*
@@ -622,26 +692,6 @@ vm_phys_alloc_pages(int domain, int pool, int order)
return (m);
}
return (NULL);
-}
-
-int
-vm_phys_alloc_npages(int domain, int pool, vm_page_t *mp, int cnt)
-{
- vm_page_t m;
- int order, freelist;
-
- for (freelist = 0; freelist < VM_NFREELIST; freelist++) {
- for (order = fls(cnt) -1; order >= 0; order--) {
- m = vm_phys_alloc_freelist_pages(domain, freelist,
- pool, order);
- if (m != NULL) {
- *mp = m;
- return (1 << order);
- }
- }
- }
- *mp = NULL;
- return (0);
}
/*
Modified: head/sys/vm/vm_phys.h
==============================================================================
--- head/sys/vm/vm_phys.h Tue Jun 26 18:07:16 2018 (r335673)
+++ head/sys/vm/vm_phys.h Tue Jun 26 18:29:56 2018 (r335674)
@@ -77,8 +77,8 @@ vm_page_t vm_phys_alloc_contig(int domain, u_long npag
vm_paddr_t high, u_long alignment, vm_paddr_t boundary);
vm_page_t vm_phys_alloc_freelist_pages(int domain, int freelist, int pool,
int order);
+int vm_phys_alloc_npages(int domain, int pool, int npages, vm_page_t ma[]);
vm_page_t vm_phys_alloc_pages(int domain, int pool, int order);
-int vm_phys_alloc_npages(int domain, int pool, vm_page_t *m, int cnt);
int vm_phys_domain_match(int prefer, vm_paddr_t low, vm_paddr_t high);
int vm_phys_fictitious_reg_range(vm_paddr_t start, vm_paddr_t end,
vm_memattr_t memattr);
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