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vm: Round up npages and alignment for contig reclamation

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When searching for runs to reclaim, we need to ensure that the entire
run will be added to the buddy allocator as a single unit.  Otherwise,
it will not be visible to vm_phys_alloc_contig() as it is currently
implemented.  This is a problem for allocation requests that are not a
power of 2 in size, as with 9KB jumbo mbuf clusters.

Reported by:	alc
Reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D28924

(cherry picked from commit 0401989282)
This commit is contained in:
Mark Johnston 2021-03-02 10:19:53 -05:00
parent 3a0ffc48b7
commit 03984bdfa0
1 changed files with 14 additions and 2 deletions
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16
sys/vm/vm_page.c
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@ -2972,17 +2972,29 @@ vm_page_reclaim_contig_domain(int domain, int req, u_long npages,
struct vm_domain *vmd;
vm_paddr_t curr_low;
vm_page_t m_run, m_runs[NRUNS];
u_long count, reclaimed;
u_long count, minalign, reclaimed;
int error, i, options, req_class;
KASSERT(npages > 0, ("npages is 0"));
KASSERT(powerof2(alignment), ("alignment is not a power of 2"));
KASSERT(powerof2(boundary), ("boundary is not a power of 2"));
req_class = req & VM_ALLOC_CLASS_MASK;
/*
* The caller will attempt an allocation after some runs have been
* reclaimed and added to the vm_phys buddy lists. Due to limitations
* of vm_phys_alloc_contig(), round up the requested length to the next
* power of two or maximum chunk size, and ensure that each run is
* suitably aligned.
*/
minalign = 1ul << imin(flsl(npages - 1), VM_NFREEORDER - 1);
npages = roundup2(npages, minalign);
if (alignment < ptoa(minalign))
alignment = ptoa(minalign);
/*
* The page daemon is allowed to dig deeper into the free page list.
*/
req_class = req & VM_ALLOC_CLASS_MASK;
if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT)
req_class = VM_ALLOC_SYSTEM;