LinuxPPC-Dev Archive on lore.kernel.org
 help / color / Atom feed
From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: linux-hyperv@vger.kernel.org, "Michal Hocko" <mhocko@suse.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	kvm@vger.kernel.org, "David Hildenbrand" <david@redhat.com>,
	"KarimAllah Ahmed" <karahmed@amazon.de>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	"Alexander Duyck" <alexander.duyck@gmail.com>,
	"Michal Hocko" <mhocko@kernel.org>,
	linux-mm@kvack.org,
	"Pavel Tatashin" <pavel.tatashin@microsoft.com>,
	"Paul Mackerras" <paulus@samba.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"Wanpeng Li" <wanpengli@tencent.com>,
	"Alexander Duyck" <alexander.h.duyck@linux.intel.com>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Kees Cook" <keescook@chromium.org>,
	devel@driverdev.osuosl.org,
	"Stefano Stabellini" <sstabellini@kernel.org>,
	"Stephen Hemminger" <sthemmin@microsoft.com>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	"Joerg Roedel" <joro@8bytes.org>,
	x86@kernel.org, YueHaibing <yuehaibing@huawei.com>,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	"Mike Rapoport" <rppt@linux.ibm.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Vlastimil Babka" <vbabka@suse.cz>,
	"Anthony Yznaga" <anthony.yznaga@oracle.com>,
	"Oscar Salvador" <osalvador@suse.de>,
	"Isaac J. Manjarres" <isaacm@codeaurora.org>,
	"Matt Sickler" <Matt.Sickler@daktronics.com>,
	"Juergen Gross" <jgross@suse.com>,
	"Anshuman Khandual" <anshuman.khandual@arm.com>,
	"Haiyang Zhang" <haiyangz@microsoft.com>,
	"Sasha Levin" <sashal@kernel.org>,
	kvm-ppc@vger.kernel.org, "Qian Cai" <cai@lca.pw>,
	"Alex Williamson" <alex.williamson@redhat.com>,
	"Mike Rapoport" <rppt@linux.vnet.ibm.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"Nicholas Piggin" <npiggin@gmail.com>,
	"Andy Lutomirski" <luto@kernel.org>,
	xen-devel@lists.xenproject.org,
	"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
	"Vitaly Kuznetsov" <vkuznets@redhat.com>,
	"Allison Randal" <allison@lohutok.net>,
	"Jim Mattson" <jmattson@google.com>,
	"Mel Gorman" <mgorman@techsingularity.net>,
	"Cornelia Huck" <cohuck@redhat.com>,
	"Pavel Tatashin" <pasha.tatashin@soleen.com>,
	"Sean Christopherson" <sean.j.christopherson@intel.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Johannes Weiner" <hannes@cmpxchg.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v1 00/10] mm: Don't mark hotplugged pages PG_reserved (including ZONE_DEVICE)
Date: Thu, 24 Oct 2019 14:09:28 +0200
Message-ID: <20191024120938.11237-1-david@redhat.com> (raw)

This is the result of a recent discussion with Michal ([1], [2]). Right
now we set all pages PG_reserved when initializing hotplugged memmaps. This
includes ZONE_DEVICE memory. In case of system memory, PG_reserved is
cleared again when onlining the memory, in case of ZONE_DEVICE memory
never.

In ancient times, we needed PG_reserved, because there was no way to tell
whether the memmap was already properly initialized. We now have
SECTION_IS_ONLINE for that in the case of !ZONE_DEVICE memory. ZONE_DEVICE
memory is already initialized deferred, and there shouldn't be a visible
change in that regard.

One of the biggest fears were side effects. I went ahead and audited all
users of PageReserved(). The details can be found in "mm/memory_hotplug:
Don't mark pages PG_reserved when initializing the memmap".

This patch set adapts all relevant users of PageReserved() to keep the
existing behavior in respect to ZONE_DEVICE pages. The biggest part part
that needs changes is KVM, to keep the existing behavior (that's all I
care about in this series).

Note that this series is able to rely completely on pfn_to_online_page().
No new is_zone_device_page() calles are introduced (as requested by Dan).
We are currently discussing a way to mark also ZONE_DEVICE memmaps as
active/initialized - pfn_active() - and lightweight locking to make sure
memmaps remain active (e.g., using RCU). We might later be able to convert
some suers of pfn_to_online_page() to pfn_active(). Details can be found
in [3], however, this represents yet another cleanup/fix we'll perform
on top of this cleanup.

I only gave it a quick test with DIMMs on x86-64, but didn't test the
ZONE_DEVICE part at all (any tips for a nice QEMU setup?). Also, I didn't
test the KVM parts (especially with ZONE_DEVICE pages or no memmap at all).
Compile-tested on x86-64 and PPC.

Based on next/master. The current version (kept updated) can be found at:
    https://github.com/davidhildenbrand/linux.git online_reserved_cleanup

RFC -> v1:
- Dropped "staging/gasket: Prepare gasket_release_page() for PG_reserved
  changes"
- Dropped "staging: kpc2000: Prepare transfer_complete_cb() for PG_reserved
  changes"
- Converted "mm/usercopy.c: Prepare check_page_span() for PG_reserved
  changes" to "mm/usercopy.c: Update comment in check_page_span()
  regarding ZONE_DEVICE"
- No new users of is_zone_device_page() are introduced.
- Rephrased comments and patch descriptions.

[1] https://lkml.org/lkml/2019/10/21/736
[2] https://lkml.org/lkml/2019/10/21/1034
[3] https://www.spinics.net/lists/linux-mm/msg194112.html

Cc: Michal Hocko <mhocko@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: kvm-ppc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: kvm@vger.kernel.org
Cc: linux-hyperv@vger.kernel.org
Cc: devel@driverdev.osuosl.org
Cc: xen-devel@lists.xenproject.org
Cc: x86@kernel.org
Cc: Alexander Duyck <alexander.duyck@gmail.com>

David Hildenbrand (10):
  mm/memory_hotplug: Don't allow to online/offline memory blocks with
    holes
  KVM: x86/mmu: Prepare kvm_is_mmio_pfn() for PG_reserved changes
  KVM: Prepare kvm_is_reserved_pfn() for PG_reserved changes
  vfio/type1: Prepare is_invalid_reserved_pfn() for PG_reserved changes
  powerpc/book3s: Prepare kvmppc_book3s_instantiate_page() for
    PG_reserved changes
  powerpc/64s: Prepare hash_page_do_lazy_icache() for PG_reserved
    changes
  powerpc/mm: Prepare maybe_pte_to_page() for PG_reserved changes
  x86/mm: Prepare __ioremap_check_ram() for PG_reserved changes
  mm/memory_hotplug: Don't mark pages PG_reserved when initializing the
    memmap
  mm/usercopy.c: Update comment in check_page_span() regarding
    ZONE_DEVICE

 arch/powerpc/kvm/book3s_64_mmu_radix.c | 14 +++++----
 arch/powerpc/mm/book3s64/hash_utils.c  | 10 +++---
 arch/powerpc/mm/pgtable.c              | 10 +++---
 arch/x86/kvm/mmu.c                     | 29 ++++++++++-------
 arch/x86/mm/ioremap.c                  | 13 ++++++--
 drivers/hv/hv_balloon.c                |  6 ++++
 drivers/vfio/vfio_iommu_type1.c        | 10 ++++--
 drivers/xen/balloon.c                  |  7 +++++
 include/linux/page-flags.h             |  8 +----
 mm/memory_hotplug.c                    | 43 +++++++++++++++++++-------
 mm/page_alloc.c                        | 11 -------
 mm/usercopy.c                          |  6 ++--
 virt/kvm/kvm_main.c                    | 10 ++++--
 13 files changed, 111 insertions(+), 66 deletions(-)

-- 
2.21.0


             reply index

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-24 12:09 David Hildenbrand [this message]
2019-10-24 12:09 ` [PATCH v1 01/10] mm/memory_hotplug: Don't allow to online/offline memory blocks with holes David Hildenbrand
2019-11-05  1:30   ` Dan Williams
2019-11-05  9:31     ` David Hildenbrand
2019-10-24 12:09 ` [PATCH v1 02/10] KVM: x86/mmu: Prepare kvm_is_mmio_pfn() for PG_reserved changes David Hildenbrand
2019-11-05  1:37   ` Dan Williams
2019-11-05 11:09     ` David Hildenbrand
2019-10-24 12:09 ` [PATCH v1 03/10] KVM: Prepare kvm_is_reserved_pfn() " David Hildenbrand
2019-11-05  4:38   ` Dan Williams
2019-11-05  9:17     ` David Hildenbrand
2019-11-05  9:49       ` David Hildenbrand
2019-11-05 10:02         ` David Hildenbrand
2019-11-05 16:00           ` Sean Christopherson
2019-11-05 20:30             ` David Hildenbrand
2019-11-05 22:22               ` Sean Christopherson
2019-11-05 23:02               ` Dan Williams
2019-11-05 23:13                 ` Sean Christopherson
2019-11-05 23:30                   ` Dan Williams
2019-11-05 23:42                     ` Sean Christopherson
2019-11-05 23:43                     ` Dan Williams
2019-11-06  0:03                       ` Sean Christopherson
2019-11-06  0:08                         ` Dan Williams
2019-11-06  6:56                           ` David Hildenbrand
2019-11-06 16:09                             ` Sean Christopherson
2019-10-24 12:09 ` [PATCH v1 04/10] vfio/type1: Prepare is_invalid_reserved_pfn() " David Hildenbrand
2019-11-07 15:40   ` Dan Williams
2019-11-07 18:22     ` David Hildenbrand
2019-11-07 22:07       ` David Hildenbrand
2019-11-08  5:09         ` Dan Williams
2019-11-08  7:14           ` David Hildenbrand
2019-11-08 10:21             ` David Hildenbrand
2019-11-08 18:29               ` Dan Williams
2019-11-08 23:01                 ` David Hildenbrand
2019-10-24 12:09 ` [PATCH v1 05/10] powerpc/book3s: Prepare kvmppc_book3s_instantiate_page() " David Hildenbrand
2019-10-24 12:09 ` [PATCH v1 06/10] powerpc/64s: Prepare hash_page_do_lazy_icache() " David Hildenbrand
2019-10-24 12:09 ` [PATCH v1 07/10] powerpc/mm: Prepare maybe_pte_to_page() " David Hildenbrand
2019-10-24 12:09 ` [PATCH v1 08/10] x86/mm: Prepare __ioremap_check_ram() " David Hildenbrand
2019-10-24 12:09 ` [PATCH v1 09/10] mm/memory_hotplug: Don't mark pages PG_reserved when initializing the memmap David Hildenbrand
2019-11-04 22:44   ` Boris Ostrovsky
2019-11-05 10:18     ` David Hildenbrand
2019-11-05 16:06       ` Boris Ostrovsky
2019-10-24 12:09 ` [PATCH v1 10/10] mm/usercopy.c: Update comment in check_page_span() regarding ZONE_DEVICE David Hildenbrand
2019-11-01 19:24 ` [PATCH v1 00/10] mm: Don't mark hotplugged pages PG_reserved (including ZONE_DEVICE) David Hildenbrand

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191024120938.11237-1-david@redhat.com \
    --to=david@redhat.com \
    --cc=Matt.Sickler@daktronics.com \
    --cc=akpm@linux-foundation.org \
    --cc=alex.williamson@redhat.com \
    --cc=alexander.duyck@gmail.com \
    --cc=alexander.h.duyck@linux.intel.com \
    --cc=allison@lohutok.net \
    --cc=aneesh.kumar@linux.ibm.com \
    --cc=anshuman.khandual@arm.com \
    --cc=anthony.yznaga@oracle.com \
    --cc=boris.ostrovsky@oracle.com \
    --cc=bp@alien8.de \
    --cc=cai@lca.pw \
    --cc=cohuck@redhat.com \
    --cc=dan.j.williams@intel.com \
    --cc=dave.hansen@linux.intel.com \
    --cc=devel@driverdev.osuosl.org \
    --cc=haiyangz@microsoft.com \
    --cc=hannes@cmpxchg.org \
    --cc=hpa@zytor.com \
    --cc=isaacm@codeaurora.org \
    --cc=jgross@suse.com \
    --cc=jmattson@google.com \
    --cc=joro@8bytes.org \
    --cc=karahmed@amazon.de \
    --cc=keescook@chromium.org \
    --cc=kvm-ppc@vger.kernel.org \
    --cc=kvm@vger.kernel.org \
    --cc=kys@microsoft.com \
    --cc=linux-hyperv@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=luto@kernel.org \
    --cc=mgorman@techsingularity.net \
    --cc=mhocko@kernel.org \
    --cc=mhocko@suse.com \
    --cc=mingo@redhat.com \
    --cc=npiggin@gmail.com \
    --cc=osalvador@suse.de \
    --cc=pasha.tatashin@soleen.com \
    --cc=paulus@samba.org \
    --cc=pavel.tatashin@microsoft.com \
    --cc=pbonzini@redhat.com \
    --cc=peterz@infradead.org \
    --cc=rkrcmar@redhat.com \
    --cc=rppt@linux.ibm.com \
    --cc=rppt@linux.vnet.ibm.com \
    --cc=sashal@kernel.org \
    --cc=sean.j.christopherson@intel.com \
    --cc=sstabellini@kernel.org \
    --cc=sthemmin@microsoft.com \
    --cc=tglx@linutronix.de \
    --cc=vbabka@suse.cz \
    --cc=vkuznets@redhat.com \
    --cc=wanpengli@tencent.com \
    --cc=willy@infradead.org \
    --cc=x86@kernel.org \
    --cc=xen-devel@lists.xenproject.org \
    --cc=yuehaibing@huawei.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LinuxPPC-Dev Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linuxppc-dev/0 linuxppc-dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linuxppc-dev linuxppc-dev/ https://lore.kernel.org/linuxppc-dev \
		linuxppc-dev@lists.ozlabs.org linuxppc-dev@ozlabs.org
	public-inbox-index linuxppc-dev

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.ozlabs.lists.linuxppc-dev


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git