Date: Tue, 2 Mar 2021 15:21:08 GMT From: Mark Johnston <markj@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 0401989282d1 - main - vm: Round up npages and alignment for contig reclamation Message-ID: <202103021521.122FL8Me051406@gitrepo.freebsd.org>
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The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=0401989282d1bb9972ae2bf4862c2c6c92ae5f27 commit 0401989282d1bb9972ae2bf4862c2c6c92ae5f27 Author: Mark Johnston <markj@FreeBSD.org> AuthorDate: 2021-03-02 15:19:53 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2021-03-02 15:21:02 +0000 vm: Round up npages and alignment for contig reclamation 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 MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D28924 --- sys/vm/vm_page.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c index 20fbbc304490..98391ccecd82 100644 --- a/sys/vm/vm_page.c +++ b/sys/vm/vm_page.c @@ -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;
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