From 60e93dc097f7f13a16a7e4b75b8803eb2adbb721 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Tue, 13 Oct 2020 16:50:39 -0700 Subject: device-dax: add dis-contiguous resource support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Break the requirement that device-dax instances are physically contiguous. With this constraint removed it allows fragmented available capacity to be fully allocated. This capability is useful to mitigate the "noisy neighbor" problem with memory-side-cache management for virtual machines, or any other scenario where a platform address boundary also designates a performance boundary. For example a direct mapped memory side cache might rotate cache colors at 1GB boundaries. With dis-contiguous allocations a device-dax instance could be configured to contain only 1 cache color. It also satisfies Joao's use case (see link) for partitioning memory for exclusive guest access. It allows for a future potential mode where the host kernel need not allocate 'struct page' capacity up-front. Reported-by: Joao Martins Signed-off-by: Dan Williams Signed-off-by: Andrew Morton Cc: Andy Lutomirski Cc: Ard Biesheuvel Cc: Ard Biesheuvel Cc: Benjamin Herrenschmidt Cc: Ben Skeggs Cc: Bjorn Helgaas Cc: Borislav Petkov Cc: Boris Ostrovsky Cc: Brice Goglin Cc: Catalin Marinas Cc: Daniel Vetter Cc: Dave Hansen Cc: Dave Jiang Cc: David Airlie Cc: David Hildenbrand Cc: Greg Kroah-Hartman Cc: "H. Peter Anvin" Cc: Hulk Robot Cc: Ingo Molnar Cc: Ira Weiny Cc: Jason Gunthorpe Cc: Jason Yan Cc: Jeff Moyer Cc: "Jérôme Glisse" Cc: Jia He Cc: Jonathan Cameron Cc: Juergen Gross Cc: kernel test robot Cc: Michael Ellerman Cc: Mike Rapoport Cc: Paul Mackerras Cc: Pavel Tatashin Cc: Peter Zijlstra Cc: "Rafael J. Wysocki" Cc: Randy Dunlap Cc: Stefano Stabellini Cc: Thomas Gleixner Cc: Tom Lendacky Cc: Vishal Verma Cc: Vivek Goyal Cc: Wei Yang Cc: Will Deacon Link: https://lore.kernel.org/lkml/20200110190313.17144-1-joao.m.martins@oracle.com/ Link: https://lkml.kernel.org/r/159643104304.4062302.16561669534797528660.stgit@dwillia2-desk3.amr.corp.intel.com Link: https://lkml.kernel.org/r/160106116875.30709.11456649969327399771.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Linus Torvalds --- tools/testing/nvdimm/dax-dev.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) (limited to 'tools/testing') diff --git a/tools/testing/nvdimm/dax-dev.c b/tools/testing/nvdimm/dax-dev.c index 38d8e55c4a0d..fb342a8c98d3 100644 --- a/tools/testing/nvdimm/dax-dev.c +++ b/tools/testing/nvdimm/dax-dev.c @@ -9,11 +9,18 @@ phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff, unsigned long size) { - struct range *range = &dev_dax->range; - phys_addr_t addr; + int i; - addr = pgoff * PAGE_SIZE + range->start; - if (addr >= range->start && addr <= range->end) { + for (i = 0; i < dev_dax->nr_range; i++) { + struct dev_dax_range *dax_range = &dev_dax->ranges[i]; + struct range *range = &dax_range->range; + unsigned long long pgoff_end; + phys_addr_t addr; + + pgoff_end = dax_range->pgoff + PHYS_PFN(range_len(range)) - 1; + if (pgoff < dax_range->pgoff || pgoff > pgoff_end) + continue; + addr = PFN_PHYS(pgoff - dax_range->pgoff) + range->start; if (addr + size - 1 <= range->end) { if (get_nfit_res(addr)) { struct page *page; @@ -23,9 +30,10 @@ phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff, page = vmalloc_to_page((void *)addr); return PFN_PHYS(page_to_pfn(page)); - } else - return addr; + } + return addr; } + break; } return -1; } -- cgit v1.2.3