linux-kernel - RE: [PATCH v2 2/2] arm64: mm: reserve per-numa CMA after numa

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <B926444035E5E2439431908E3842AFD2524297@DGGEMI525-MBS.china.huawei.com>
Date:   Fri, 26 Jun 2020 03:44:04 +0000
From:   "Song Bao Hua (Barry Song)" <song.bao.hua@...ilicon.com>
To:     Robin Murphy <robin.murphy@....com>, "hch@....de" <hch@....de>,
        "m.szyprowski@...sung.com" <m.szyprowski@...sung.com>,
        "will@...nel.org" <will@...nel.org>,
        "ganapatrao.kulkarni@...ium.com" <ganapatrao.kulkarni@...ium.com>,
        "catalin.marinas@....com" <catalin.marinas@....com>
CC:     "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
        Linuxarm <linuxarm@...wei.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
        Steve Capper <steve.capper@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mike Rapoport <rppt@...ux.ibm.com>
Subject: RE: [PATCH v2 2/2] arm64: mm: reserve per-numa CMA after numa_init



> -----Original Message-----
> From: Robin Murphy [mailto:robin.murphy@....com]
> Sent: Thursday, June 25, 2020 11:16 PM
> To: Song Bao Hua (Barry Song) <song.bao.hua@...ilicon.com>; hch@....de;
> m.szyprowski@...sung.com; will@...nel.org;
> ganapatrao.kulkarni@...ium.com; catalin.marinas@....com
> Cc: iommu@...ts.linux-foundation.org; Linuxarm <linuxarm@...wei.com>;
> linux-arm-kernel@...ts.infradead.org; linux-kernel@...r.kernel.org; Nicolas
> Saenz Julienne <nsaenzjulienne@...e.de>; Steve Capper
> <steve.capper@....com>; Andrew Morton <akpm@...ux-foundation.org>;
> Mike Rapoport <rppt@...ux.ibm.com>
> Subject: Re: [PATCH v2 2/2] arm64: mm: reserve per-numa CMA after
> numa_init
> 
> On 2020-06-25 08:43, Barry Song wrote:
> > Right now, smmu is using dma_alloc_coherent() to get memory to save
> queues
> > and tables. Typically, on ARM64 server, there is a default CMA located at
> > node0, which could be far away from node2, node3 etc.
> > with this patch, smmu will get memory from local numa node to save
> command
> > queues and page tables. that means dma_unmap latency will be shrunk
> much.
> > Meanwhile, when iommu.passthrough is on, device drivers which call dma_
> > alloc_coherent() will also get local memory and avoid the travel between
> > numa nodes.
> >
> > Cc: Christoph Hellwig <hch@....de>
> > Cc: Marek Szyprowski <m.szyprowski@...sung.com>
> > Cc: Will Deacon <will@...nel.org>
> > Cc: Robin Murphy <robin.murphy@....com>
> > Cc: Ganapatrao Kulkarni <ganapatrao.kulkarni@...ium.com>
> > Cc: Catalin Marinas <catalin.marinas@....com>
> > Cc: Nicolas Saenz Julienne <nsaenzjulienne@...e.de>
> > Cc: Steve Capper <steve.capper@....com>
> > Cc: Andrew Morton <akpm@...ux-foundation.org>
> > Cc: Mike Rapoport <rppt@...ux.ibm.com>
> > Signed-off-by: Barry Song <song.bao.hua@...ilicon.com>
> > ---
> >   arch/arm64/mm/init.c | 2 ++
> >   1 file changed, 2 insertions(+)
> >
> > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> > index 1e93cfc7c47a..07d4d1fe7983 100644
> > --- a/arch/arm64/mm/init.c
> > +++ b/arch/arm64/mm/init.c
> > @@ -420,6 +420,8 @@ void __init bootmem_init(void)
> >
> >   	arm64_numa_init();
> >
> > +	dma_pernuma_cma_reserve();
> > +
> 
> It might be worth putting this after the hugetlb_cma_reserve() call for
> clarity, since the comment below applies equally to this call too.

Yep, it looks even better though dma_pernuma_cma_reserve() is self-documenting by name.

> 
> Robin.
> 
> >   	/*
> >   	 * must be done after arm64_numa_init() which calls numa_init() to
> >   	 * initialize node_online_map that gets used in hugetlb_cma_reserve()
> >
Thanks
Barry