From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f182.google.com (mail-pl1-f182.google.com [209.85.214.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BD182168 for ; Mon, 2 Aug 2021 14:06:32 +0000 (UTC) Received: by mail-pl1-f182.google.com with SMTP id q2so19709646plr.11 for ; Mon, 02 Aug 2021 07:06:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=S30D7JnOgPGqBVRgaO8L0r6DfESVg4Q0tFc852vuoQg=; b=o7zchrRzGSGJvS1YaJA1zPgb9ncAEmQmS7wdtDRLvzTCTV0KV5fs6bh0F0NjLGNQdA hAsch3Th8KrrnTB3oABOyV9xGiM0mqxvjwcQkfhvu6p+CzBkBfEJS62qGuplsCP//3yg Y/7Pd6ryCB0f1VkCo8aXIsC1y4zhgDxhhN+SRDfojcY9OlwszZt73S0OMdSAGrrt/lEF DAL3uoym+fNdBMYLmsgLkKHhyp31BFULI/YtTh4pTa9xWKYuYTipXMvvP+ON9z6AxU2Y Ley1Tyza1FWHdyq3dJxbBTwJofGKtCqvbKWZgl3yHMFRcxOB/Pt8dJtPdR+vN52DMLVv 44lw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=S30D7JnOgPGqBVRgaO8L0r6DfESVg4Q0tFc852vuoQg=; b=dYiZvifEMlH2A3mAAKpmEH+sazP5dTW4lT9eNVETEwTxyJqWM5pDlliefuBgYoURwR 2B5vYFFbPcvmy54fJQo0bRBR289Gah6cfDGIKHsWwxY+juhINP+R3Z6dRNhPaKX6UmAb S7cVivtIHDusVjxYOmxQ8gAXg6ibOJLChbITxso3M2yMUsUxFJUhDkfoMPACrzpxeS+0 p2+YWAXfSHNOkbwajBea9DJlv9NJgGQzRVyTPmx/rgBNu1MEfPQnRYrK9j7zeVu+5WAG FFWuF4OrKGbh2A9P4S3a2Zy8RgJDj1P2ZQviCspCu/JdpVv2ha9f2uaJE4Ac2YkflfZm oU5Q== X-Gm-Message-State: AOAM532grVFIr5lEkjIJruxJvfsF0gd+FPuU7JTmflx6cNxgsj64D0Nl BogPfUNDA8MyIwLDuE7iW5g5S8qrHy1JUHURKIqtWg== X-Google-Smtp-Source: ABdhPJyVKOnhVt0Wdh9gR5klKUeMY8LJl9xOy+rXAR1aL3gh/RyX3d+gIGycEUJ0HTA94nfjLHThyGCadYvcoTFdMUM= X-Received: by 2002:a65:6248:: with SMTP id q8mr1176705pgv.279.1627913192152; Mon, 02 Aug 2021 07:06:32 -0700 (PDT) Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20210714193542.21857-1-joao.m.martins@oracle.com> <20210714144830.29f9584878b04903079ef7eb@linux-foundation.org> <5642c8c3-cf13-33dc-c617-9d1becfba1b1@oracle.com> In-Reply-To: From: Dan Williams Date: Mon, 2 Aug 2021 07:06:21 -0700 Message-ID: Subject: Re: [PATCH v3 00/14] mm, sparse-vmemmap: Introduce compound pagemaps To: Joao Martins Cc: Matthew Wilcox , Andrew Morton , Linux MM , Vishal Verma , Dave Jiang , Naoya Horiguchi , Jason Gunthorpe , John Hubbard , Jane Chu , Muchun Song , Mike Kravetz , Jonathan Corbet , Linux NVDIMM , Linux Doc Mailing List Content-Type: text/plain; charset="UTF-8" On Mon, Aug 2, 2021 at 3:41 AM Joao Martins wrote: > > > > On 7/28/21 12:23 AM, Dan Williams wrote: > > On Thu, Jul 22, 2021 at 3:54 AM Joao Martins wrote: > > [..] > >>> The folio work really touches the page > >>> cache for now, and this seems mostly to touch the devmap paths. > >>> > >> /me nods -- it really is about devmap infra for usage in device-dax for persistent memory. > >> > >> Perhaps I should do s/pagemaps/devmap/ throughout the series to avoid confusion. > > > > I also like "devmap" as a more accurate name. It matches the PFN_DEV > > and PFN_MAP flags that decorate DAX capable pfn_t instances. It also > > happens to match a recommendation I gave to Ira for his support for > > supervisor protection keys with devmap pfns. > > > /me nods > > Additionally, I think I'll be reordering the patches for more clear/easier > bisection i.e. first introducing compound pages for devmap, fixing associated > issues wrt to the slow pinning and then introduce vmemmap deduplication for > devmap. > > It should look like below after the reordering from first patch to last. > Let me know if you disagree. > > memory-failure: fetch compound_head after pgmap_pfn_valid() > mm/page_alloc: split prep_compound_page into head and tail subparts > mm/page_alloc: refactor memmap_init_zone_device() page init > mm/memremap: add ZONE_DEVICE support for compound pages > device-dax: use ALIGN() for determining pgoff > device-dax: compound devmap support > mm/gup: grab head page refcount once for group of subpages > mm/sparse-vmemmap: add a pgmap argument to section activation > mm/sparse-vmemmap: refactor core of vmemmap_populate_basepages() to helper > mm/hugetlb_vmemmap: move comment block to Documentation/vm > mm/sparse-vmemmap: populate compound devmaps > mm/page_alloc: reuse tail struct pages for compound devmaps > mm/sparse-vmemmap: improve memory savings for compound pud geometry LGTM.