From: Ralph Campbell <rcampbell@nvidia.com> To: <linux-mm@kvack.org>, <kvm-ppc@vger.kernel.org>, <linux-kselftest@vger.kernel.org>, <linux-kernel@vger.kernel.org> Cc: Jerome Glisse <jglisse@redhat.com>, John Hubbard <jhubbard@nvidia.com>, Christoph Hellwig <hch@lst.de>, Jason Gunthorpe <jgg@mellanox.com>, "Bharata B Rao" <bharata@linux.ibm.com>, Shuah Khan <shuah@kernel.org>, Andrew Morton <akpm@linux-foundation.org>, Ralph Campbell <rcampbell@nvidia.com> Subject: [PATCH v2 1/2] mm/migrate: optimize migrate_vma_setup() for holes Date: Fri, 10 Jul 2020 12:48:39 -0700 [thread overview] Message-ID: <20200710194840.7602-2-rcampbell@nvidia.com> (raw) In-Reply-To: <20200710194840.7602-1-rcampbell@nvidia.com> When migrating system memory to device private memory, if the source address range is a valid VMA range and there is no memory or a zero page, the source PFN array is marked as valid but with no PFN. This lets the device driver allocate private memory and clear it, then insert the new device private struct page into the CPU's page tables when migrate_vma_pages() is called. migrate_vma_pages() only inserts the new page if the VMA is an anonymous range. There is no point in telling the device driver to allocate device private memory and then not migrate the page. Instead, mark the source PFN array entries as not migrating to avoid this overhead. Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> --- mm/migrate.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index b0125c082549..ec00b7a6ea2a 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2205,6 +2205,16 @@ static int migrate_vma_collect_hole(unsigned long start, struct migrate_vma *migrate = walk->private; unsigned long addr; + /* Only allow populating anonymous memory. */ + if (!vma_is_anonymous(walk->vma)) { + for (addr = start; addr < end; addr += PAGE_SIZE) { + migrate->src[migrate->npages] = 0; + migrate->dst[migrate->npages] = 0; + migrate->npages++; + } + return 0; + } + for (addr = start; addr < end; addr += PAGE_SIZE) { migrate->src[migrate->npages] = MIGRATE_PFN_MIGRATE; migrate->dst[migrate->npages] = 0; @@ -2297,8 +2307,10 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp, pte = *ptep; if (pte_none(pte)) { - mpfn = MIGRATE_PFN_MIGRATE; - migrate->cpages++; + if (vma_is_anonymous(vma)) { + mpfn = MIGRATE_PFN_MIGRATE; + migrate->cpages++; + } goto next; } -- 2.20.1
WARNING: multiple messages have this Message-ID (diff)
From: Ralph Campbell <rcampbell@nvidia.com> To: linux-mm@kvack.org, kvm-ppc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Jerome Glisse <jglisse@redhat.com>, John Hubbard <jhubbard@nvidia.com>, Christoph Hellwig <hch@lst.de>, Jason Gunthorpe <jgg@mellanox.com>, Bharata B Rao <bharata@linux.ibm.com>, Shuah Khan <shuah@kernel.org>, Andrew Morton <akpm@linux-foundation.org>, Ralph Campbell <rcampbell@nvidia.com> Subject: [PATCH v2 1/2] mm/migrate: optimize migrate_vma_setup() for holes Date: Fri, 10 Jul 2020 19:48:39 +0000 [thread overview] Message-ID: <20200710194840.7602-2-rcampbell@nvidia.com> (raw) In-Reply-To: <20200710194840.7602-1-rcampbell@nvidia.com> When migrating system memory to device private memory, if the source address range is a valid VMA range and there is no memory or a zero page, the source PFN array is marked as valid but with no PFN. This lets the device driver allocate private memory and clear it, then insert the new device private struct page into the CPU's page tables when migrate_vma_pages() is called. migrate_vma_pages() only inserts the new page if the VMA is an anonymous range. There is no point in telling the device driver to allocate device private memory and then not migrate the page. Instead, mark the source PFN array entries as not migrating to avoid this overhead. Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> --- mm/migrate.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index b0125c082549..ec00b7a6ea2a 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2205,6 +2205,16 @@ static int migrate_vma_collect_hole(unsigned long start, struct migrate_vma *migrate = walk->private; unsigned long addr; + /* Only allow populating anonymous memory. */ + if (!vma_is_anonymous(walk->vma)) { + for (addr = start; addr < end; addr += PAGE_SIZE) { + migrate->src[migrate->npages] = 0; + migrate->dst[migrate->npages] = 0; + migrate->npages++; + } + return 0; + } + for (addr = start; addr < end; addr += PAGE_SIZE) { migrate->src[migrate->npages] = MIGRATE_PFN_MIGRATE; migrate->dst[migrate->npages] = 0; @@ -2297,8 +2307,10 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp, pte = *ptep; if (pte_none(pte)) { - mpfn = MIGRATE_PFN_MIGRATE; - migrate->cpages++; + if (vma_is_anonymous(vma)) { + mpfn = MIGRATE_PFN_MIGRATE; + migrate->cpages++; + } goto next; } -- 2.20.1
next prev parent reply other threads:[~2020-07-10 19:49 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-07-10 19:48 [PATCH v2 0/2] mm/migrate: optimize migrate_vma_setup() for holes Ralph Campbell 2020-07-10 19:48 ` Ralph Campbell 2020-07-10 19:48 ` Ralph Campbell [this message] 2020-07-10 19:48 ` [PATCH v2 1/2] " Ralph Campbell 2020-07-10 19:48 ` [PATCH v2 2/2] mm/migrate: add migrate-shared test for migrate_vma_*() Ralph Campbell 2020-07-10 19:48 ` Ralph Campbell
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