Date: Thu, 31 Mar 2022 21:23:01 GMT From: Doug Moore <dougm@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 557dc337e6cb - main - vm_phys: check small blocks to finish allocation Message-ID: <202203312123.22VLN1S2028889@gitrepo.freebsd.org>
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The branch main has been updated by dougm: URL: https://cgit.FreeBSD.org/src/commit/?id=557dc337e6cb6664a322c3988632b5ca75ff33ed commit 557dc337e6cb6664a322c3988632b5ca75ff33ed Author: Doug Moore <dougm@FreeBSD.org> AuthorDate: 2022-03-31 21:19:55 +0000 Commit: Doug Moore <dougm@FreeBSD.org> CommitDate: 2022-03-31 21:19:55 +0000 vm_phys: check small blocks to finish allocation In vm_phys_alloc_queues_contig, in the case that a sequence of max-order blocks are sought to fulfill an allocation, a sequence is ruled out if it does not have enough max-order blocks to satisfy the allocation. However, there may be smaller blocks of free memory that follow the last max-order block in the sequence, and they may be big enough to complete the allocation request, so check for that possibility before giving up on that block sequence. Reviewed by: markj Tested by: pho Differential Revision: https://reviews.freebsd.org/D34724 --- sys/vm/vm_phys.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) diff --git a/sys/vm/vm_phys.c b/sys/vm/vm_phys.c index 1f4c228b1a84..33c46fe7c481 100644 --- a/sys/vm/vm_phys.c +++ b/sys/vm/vm_phys.c @@ -1405,9 +1405,9 @@ vm_phys_alloc_queues_contig( continue; /* - * Determine if a sufficient number of - * subsequent blocks to satisfy the - * allocation request are free. + * Determine if a series of free oind-blocks + * starting here can satisfy the allocation + * request. */ do { pa += 1 << @@ -1416,6 +1416,23 @@ vm_phys_alloc_queues_contig( goto done; } while (VM_NFREEORDER - 1 == seg->first_page[ atop(pa - seg->start)].order); + + /* + * Determine if an additional series of free + * blocks of diminishing size can help to + * satisfy the allocation request. + */ + for (;;) { + m = &seg->first_page[ + atop(pa - seg->start)]; + if (m->order == VM_NFREEORDER || + pa + (2 << (PAGE_SHIFT + m->order)) + <= pa_end) + break; + pa += 1 << (PAGE_SHIFT + m->order); + if (pa >= pa_end) + goto done; + } } } } @@ -1423,6 +1440,7 @@ vm_phys_alloc_queues_contig( done: for (m = m_ret; m < &m_ret[npages]; m = &m[1 << oind]) { fl = (*queues)[m->pool]; + oind = m->order; vm_freelist_rem(fl, m, oind); if (m->pool != VM_FREEPOOL_DEFAULT) vm_phys_set_pool(VM_FREEPOOL_DEFAULT, m, oind);
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