Date: Sat, 5 Aug 2023 02:11:37 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: e77f4e7f5972 - main - vm_phys: tune vm_phys_enqueue_contig loop Message-ID: <202308050211.3752Bb1I004017@gitrepo.freebsd.org>
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The branch main has been updated by dougm: URL: https://cgit.FreeBSD.org/src/commit/?id=e77f4e7f597261bc873227a0dfc05d178c367727 commit e77f4e7f597261bc873227a0dfc05d178c367727 Author: Doug Moore <dougm@FreeBSD.org> AuthorDate: 2023-08-05 02:09:39 +0000 Commit: Doug Moore <dougm@FreeBSD.org> CommitDate: 2023-08-05 02:09:39 +0000 vm_phys: tune vm_phys_enqueue_contig loop Rewrite the final loop in vm_phys_enqueue_contig as a new function, vm_phys_enq_beg, to reduce amd64 code size. Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D41289 --- sys/vm/vm_phys.c | 44 ++++++++++++++++++++++++++++++++++++-------- 1 file changed, 36 insertions(+), 8 deletions(-) diff --git a/sys/vm/vm_phys.c b/sys/vm/vm_phys.c index a3af3964fba4..bc9db6559bfe 100644 --- a/sys/vm/vm_phys.c +++ b/sys/vm/vm_phys.c @@ -680,6 +680,41 @@ vm_phys_split_pages(vm_page_t m, int oind, struct vm_freelist *fl, int order, } } +/* + * Add the physical pages [m, m + npages) at the beginning of a power-of-two + * aligned and sized set to the specified free list. + * + * When this function is called by a page allocation function, the caller + * should request insertion at the head unless the lower-order queues are + * known to be empty. The objective being to reduce the likelihood of long- + * term fragmentation by promoting contemporaneous allocation and (hopefully) + * deallocation. + * + * The physical page m's buddy must not be free. + */ +static void +vm_phys_enq_beg(vm_page_t m, u_int npages, struct vm_freelist *fl, int tail) +{ + int order; + + KASSERT(npages == 0 || + (VM_PAGE_TO_PHYS(m) & + ((PAGE_SIZE << (fls(npages) - 1)) - 1)) == 0, + ("%s: page %p and npages %u are misaligned", + __func__, m, npages)); + while (npages > 0) { + KASSERT(m->order == VM_NFREEORDER, + ("%s: page %p has unexpected order %d", + __func__, m, m->order)); + order = fls(npages) - 1; + KASSERT(order < VM_NFREEORDER, + ("%s: order %d is out of range", __func__, order)); + vm_freelist_add(fl, m, order, tail); + m += 1 << order; + npages -= 1 << order; + } +} + /* * Add the physical pages [m, m + npages) at the end of a power-of-two aligned * and sized set to the specified free list. @@ -1190,14 +1225,7 @@ vm_phys_enqueue_contig(vm_page_t m, u_long npages) m += 1 << order; } /* Free blocks of diminishing size. */ - while (m < m_end) { - KASSERT(seg == &vm_phys_segs[m->segind], - ("%s: page range [%p,%p) spans multiple segments", - __func__, m_end - npages, m)); - order = flsl(m_end - m) - 1; - vm_freelist_add(fl, m, order, 1); - m += 1 << order; - } + vm_phys_enq_beg(m, m_end - m, fl, 1); } /*
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