system/freebsd-src
system/freebsd-src
1
0
Fork 0
mirror of https://github.com/freebsd/freebsd-src synced 2024-07-22 02:37:15 +00:00
Code Issues Actions 2 Packages Projects Releases Wiki Activity

vm_phys; fix uncalled free_contig

Browse source 
Function vm_phys_free_contig does not always free memory properly when
the npages parameter is less than max block size.  Change it so that it does.

Note that this function is not currently invoked, and this error was
not triggered in earlier versions of the code.

Reviewed by:	markj
Differential Revision:	https://reviews.freebsd.org/D42891
This commit is contained in:
Doug Moore 2023-12-20 21:37:47 -06:00
parent c91cd7d03a
commit 6dd15b7a23
1 changed files with 12 additions and 26 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

38
sys/vm/vm_phys.c
View file

@ -1169,24 +1169,6 @@ vm_phys_free_pages(vm_page_t m, int order)
vm_freelist_add(fl, m, order, 1);
}
/*
* Return the largest possible order of a set of pages starting at m.
*/
static int
max_order(vm_page_t m)
{
/*
* Unsigned "min" is used here so that "order" is assigned
* "VM_NFREEORDER - 1" when "m"'s physical address is zero
* or the low-order bits of its physical address are zero
* because the size of a physical address exceeds the size of
* a long.
*/
return (min(ffsll(VM_PAGE_TO_PHYS(m) >> PAGE_SHIFT) - 1,
VM_NFREEORDER - 1));
}
/*
* Free a contiguous, arbitrarily sized set of physical pages, without
* merging across set boundaries.
@ -1211,7 +1193,7 @@ vm_phys_enqueue_contig(vm_page_t m, u_long npages)
fl = (*seg->free_queues)[m->pool];
m_end = m + npages;
/* Free blocks of increasing size. */
lo = VM_PAGE_TO_PHYS(m) >> PAGE_SHIFT;
lo = atop(VM_PAGE_TO_PHYS(m));
if (m < m_end &&
(diff = lo ^ (lo + npages - 1)) != 0) {
order = min(flsll(diff) - 1, VM_NFREEORDER - 1);
@ -1239,18 +1221,22 @@ vm_phys_enqueue_contig(vm_page_t m, u_long npages)
void
vm_phys_free_contig(vm_page_t m, u_long npages)
{
int order_start, order_end;
vm_paddr_t lo;
vm_page_t m_start, m_end;
unsigned max_order, order_start, order_end;
vm_domain_free_assert_locked(vm_pagequeue_domain(m));
lo = atop(VM_PAGE_TO_PHYS(m));
max_order = min(flsll(lo ^ (lo + npages)) - 1, VM_NFREEORDER - 1);
m_start = m;
order_start = max_order(m_start);
if (order_start < VM_NFREEORDER - 1)
order_start = ffsll(lo) - 1;
if (order_start < max_order)
m_start += 1 << order_start;
m_end = m + npages;
order_end = max_order(m_end);
if (order_end < VM_NFREEORDER - 1)
order_end = ffsll(lo + npages) - 1;
if (order_end < max_order)
m_end -= 1 << order_end;
/*
* Avoid unnecessary coalescing by freeing the pages at the start and
@ -1258,9 +1244,9 @@ vm_phys_free_contig(vm_page_t m, u_long npages)
*/
if (m_start < m_end)
vm_phys_enqueue_contig(m_start, m_end - m_start);
if (order_start < VM_NFREEORDER - 1)
if (order_start < max_order)
vm_phys_free_pages(m, order_start);
if (order_end < VM_NFREEORDER - 1)
if (order_end < max_order)
vm_phys_free_pages(m_end, order_end);
}