<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/include/linux, branch v5.3-rc5</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>Merge tag 'usb-5.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb</title>
<updated>2019-08-18T16:11:29+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-08-18T16:11:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=359334caf777854fc0647c610f4c34be5eaeb3ca'/>
<id>359334caf777854fc0647c610f4c34be5eaeb3ca</id>
<content type='text'>
Pull USB fixes from Greg KH:
 "Here are number of small USB fixes for 5.3-rc5.

  Syzbot has been on a tear recently now that it has some good USB
  debugging hooks integrated, so there's a number of fixes in here found
  by those tools for some _very_ old bugs. Also a handful of gadget
  driver fixes for reported issues, some hopefully-final dma fixes for
  host controller drivers, and some new USB serial gadget driver ids.

  All of these have been in linux-next this week with no reported issues
  (the usb-serial ones were in linux-next in its own branch, but merged
  into mine on Friday)"

* tag 'usb-5.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: add a hcd_uses_dma helper
  usb: don't create dma pools for HCDs with a localmem_pool
  usb: chipidea: imx: fix EPROBE_DEFER support during driver probe
  usb: host: fotg2: restart hcd after port reset
  USB: CDC: fix sanity checks in CDC union parser
  usb: cdc-acm: make sure a refcount is taken early enough
  USB: serial: option: add the BroadMobi BM818 card
  USB: serial: option: Add Motorola modem UARTs
  USB: core: Fix races in character device registration and deregistraion
  usb: gadget: mass_storage: Fix races between fsg_disable and fsg_set_alt
  usb: gadget: composite: Clear "suspended" on reset/disconnect
  usb: gadget: udc: renesas_usb3: Fix sysfs interface of "role"
  USB: serial: option: add D-Link DWM-222 device ID
  USB: serial: option: Add support for ZTE MF871A
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull USB fixes from Greg KH:
 "Here are number of small USB fixes for 5.3-rc5.

  Syzbot has been on a tear recently now that it has some good USB
  debugging hooks integrated, so there's a number of fixes in here found
  by those tools for some _very_ old bugs. Also a handful of gadget
  driver fixes for reported issues, some hopefully-final dma fixes for
  host controller drivers, and some new USB serial gadget driver ids.

  All of these have been in linux-next this week with no reported issues
  (the usb-serial ones were in linux-next in its own branch, but merged
  into mine on Friday)"

* tag 'usb-5.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: add a hcd_uses_dma helper
  usb: don't create dma pools for HCDs with a localmem_pool
  usb: chipidea: imx: fix EPROBE_DEFER support during driver probe
  usb: host: fotg2: restart hcd after port reset
  USB: CDC: fix sanity checks in CDC union parser
  usb: cdc-acm: make sure a refcount is taken early enough
  USB: serial: option: add the BroadMobi BM818 card
  USB: serial: option: Add Motorola modem UARTs
  USB: core: Fix races in character device registration and deregistraion
  usb: gadget: mass_storage: Fix races between fsg_disable and fsg_set_alt
  usb: gadget: composite: Clear "suspended" on reset/disconnect
  usb: gadget: udc: renesas_usb3: Fix sysfs interface of "role"
  USB: serial: option: add D-Link DWM-222 device ID
  USB: serial: option: Add support for ZTE MF871A
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus-2019-08-17' of git://git.kernel.dk/linux-block</title>
<updated>2019-08-18T02:39:54+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-08-18T02:39:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8fde2832bd0bdc5a2b57330a9e9c3d2fa16bd1d8'/>
<id>8fde2832bd0bdc5a2b57330a9e9c3d2fa16bd1d8</id>
<content type='text'>
Pull block fixes from Jens Axboe:
 "A collection of fixes that should go into this series. This contains:

   - Revert of the REQ_NOWAIT_INLINE and associated dio changes. There
     were still corner cases there, and even though I had a solution for
     it, it's too involved for this stage. (me)

   - Set of NVMe fixes (via Sagi)

   - io_uring fix for fixed buffers (Anthony)

   - io_uring defer issue fix (Jackie)

   - Regression fix for queue sync at exit time (zhengbin)

   - xen blk-back memory leak fix (Wenwen)"

* tag 'for-linus-2019-08-17' of git://git.kernel.dk/linux-block:
  io_uring: fix an issue when IOSQE_IO_LINK is inserted into defer list
  block: remove REQ_NOWAIT_INLINE
  io_uring: fix manual setup of iov_iter for fixed buffers
  xen/blkback: fix memory leaks
  blk-mq: move cancel of requeue_work to the front of blk_exit_queue
  nvme-pci: Fix async probe remove race
  nvme: fix controller removal race with scan work
  nvme-rdma: fix possible use-after-free in connect error flow
  nvme: fix a possible deadlock when passthru commands sent to a multipath device
  nvme-core: Fix extra device_put() call on error path
  nvmet-file: fix nvmet_file_flush() always returning an error
  nvmet-loop: Flush nvme_delete_wq when removing the port
  nvmet: Fix use-after-free bug when a port is removed
  nvme-multipath: revalidate nvme_ns_head gendisk in nvme_validate_ns
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull block fixes from Jens Axboe:
 "A collection of fixes that should go into this series. This contains:

   - Revert of the REQ_NOWAIT_INLINE and associated dio changes. There
     were still corner cases there, and even though I had a solution for
     it, it's too involved for this stage. (me)

   - Set of NVMe fixes (via Sagi)

   - io_uring fix for fixed buffers (Anthony)

   - io_uring defer issue fix (Jackie)

   - Regression fix for queue sync at exit time (zhengbin)

   - xen blk-back memory leak fix (Wenwen)"

* tag 'for-linus-2019-08-17' of git://git.kernel.dk/linux-block:
  io_uring: fix an issue when IOSQE_IO_LINK is inserted into defer list
  block: remove REQ_NOWAIT_INLINE
  io_uring: fix manual setup of iov_iter for fixed buffers
  xen/blkback: fix memory leaks
  blk-mq: move cancel of requeue_work to the front of blk_exit_queue
  nvme-pci: Fix async probe remove race
  nvme: fix controller removal race with scan work
  nvme-rdma: fix possible use-after-free in connect error flow
  nvme: fix a possible deadlock when passthru commands sent to a multipath device
  nvme-core: Fix extra device_put() call on error path
  nvmet-file: fix nvmet_file_flush() always returning an error
  nvmet-loop: Flush nvme_delete_wq when removing the port
  nvmet: Fix use-after-free bug when a port is removed
  nvme-multipath: revalidate nvme_ns_head gendisk in nvme_validate_ns
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'pm-5.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm</title>
<updated>2019-08-16T16:13:16+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-08-16T16:13:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2d63ba3e41db3ceb0d23924ed2879b910276e24c'/>
<id>2d63ba3e41db3ceb0d23924ed2879b910276e24c</id>
<content type='text'>
Pull power management fixes from Rafael Wysocki:
 "These add a check to avoid recent suspend-to-idle power regression on
  systems with NVMe drives where the PCIe ASPM policy is "performance"
  (or when the kernel is built without ASPM support), fix an issue
  related to frequency limits in the schedutil cpufreq governor and fix
  a mistake related to the PM QoS usage in the cpufreq core introduced
  recently.

  Specifics:

   - Disable NVMe power optimization related to suspend-to-idle added
     recently on systems where PCIe ASPM is not able to put PCIe links
     into low-power states to prevent excess power from being drawn by
     the system while suspended (Rafael Wysocki).

   - Make the schedutil governor handle frequency limits changes
     properly in all cases (Viresh Kumar).

   - Prevent the cpufreq core from treating positive values returned by
     dev_pm_qos_update_request() as errors (Viresh Kumar)"

* tag 'pm-5.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  nvme-pci: Allow PCI bus-level PM to be used if ASPM is disabled
  PCI/ASPM: Add pcie_aspm_enabled()
  cpufreq: schedutil: Don't skip freq update when limits change
  cpufreq: dev_pm_qos_update_request() can return 1 on success
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull power management fixes from Rafael Wysocki:
 "These add a check to avoid recent suspend-to-idle power regression on
  systems with NVMe drives where the PCIe ASPM policy is "performance"
  (or when the kernel is built without ASPM support), fix an issue
  related to frequency limits in the schedutil cpufreq governor and fix
  a mistake related to the PM QoS usage in the cpufreq core introduced
  recently.

  Specifics:

   - Disable NVMe power optimization related to suspend-to-idle added
     recently on systems where PCIe ASPM is not able to put PCIe links
     into low-power states to prevent excess power from being drawn by
     the system while suspended (Rafael Wysocki).

   - Make the schedutil governor handle frequency limits changes
     properly in all cases (Viresh Kumar).

   - Prevent the cpufreq core from treating positive values returned by
     dev_pm_qos_update_request() as errors (Viresh Kumar)"

* tag 'pm-5.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  nvme-pci: Allow PCI bus-level PM to be used if ASPM is disabled
  PCI/ASPM: Add pcie_aspm_enabled()
  cpufreq: schedutil: Don't skip freq update when limits change
  cpufreq: dev_pm_qos_update_request() can return 1 on success
</pre>
</div>
</content>
</entry>
<entry>
<title>block: remove REQ_NOWAIT_INLINE</title>
<updated>2019-08-15T17:09:16+00:00</updated>
<author>
<name>Jens Axboe</name>
<email>axboe@kernel.dk</email>
</author>
<published>2019-08-15T17:09:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=7b6620d7db566a46f49b4b9deab9fa061fd4b59b'/>
<id>7b6620d7db566a46f49b4b9deab9fa061fd4b59b</id>
<content type='text'>
We had a few issues with this code, and there's still a problem around
how we deal with error handling for chained/split bios. For now, just
revert the code and we'll try again with a thoroug solution. This
reverts commits:

e15c2ffa1091 ("block: fix O_DIRECT error handling for bio fragments")
0eb6ddfb865c ("block: Fix __blkdev_direct_IO() for bio fragments")
6a43074e2f46 ("block: properly handle IOCB_NOWAIT for async O_DIRECT IO")
893a1c97205a ("blk-mq: allow REQ_NOWAIT to return an error inline")

Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We had a few issues with this code, and there's still a problem around
how we deal with error handling for chained/split bios. For now, just
revert the code and we'll try again with a thoroug solution. This
reverts commits:

e15c2ffa1091 ("block: fix O_DIRECT error handling for bio fragments")
0eb6ddfb865c ("block: Fix __blkdev_direct_IO() for bio fragments")
6a43074e2f46 ("block: properly handle IOCB_NOWAIT for async O_DIRECT IO")
893a1c97205a ("blk-mq: allow REQ_NOWAIT to return an error inline")

Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>usb: add a hcd_uses_dma helper</title>
<updated>2019-08-15T13:18:05+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2019-08-11T08:05:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=edfbcb321faf07ca970e4191abe061deeb7d3788'/>
<id>edfbcb321faf07ca970e4191abe061deeb7d3788</id>
<content type='text'>
The USB buffer allocation code is the only place in the usb core (and in
fact the whole kernel) that uses is_device_dma_capable, while the URB
mapping code uses the uses_dma flag in struct usb_bus.  Switch the buffer
allocation to use the uses_dma flag used by the rest of the USB code,
and create a helper in hcd.h that checks this flag as well as the
CONFIG_HAS_DMA to simplify the caller a bit.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Link: https://lore.kernel.org/r/20190811080520.21712-3-hch@lst.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The USB buffer allocation code is the only place in the usb core (and in
fact the whole kernel) that uses is_device_dma_capable, while the URB
mapping code uses the uses_dma flag in struct usb_bus.  Switch the buffer
allocation to use the uses_dma flag used by the rest of the USB code,
and create a helper in hcd.h that checks this flag as well as the
CONFIG_HAS_DMA to simplify the caller a bit.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Link: https://lore.kernel.org/r/20190811080520.21712-3-hch@lst.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'dma-mapping-5.3-4' of git://git.infradead.org/users/hch/dma-mapping</title>
<updated>2019-08-14T17:31:11+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2019-08-14T17:31:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=e83b009c5c366b678c7986fa6c1d38fed06c954c'/>
<id>e83b009c5c366b678c7986fa6c1d38fed06c954c</id>
<content type='text'>
Pull dma-mapping fixes from Christoph Hellwig:

 - fix the handling of the bus_dma_mask in dma_get_required_mask, which
   caused a regression in this merge window (Lucas Stach)

 - fix a regression in the handling of DMA_ATTR_NO_KERNEL_MAPPING (me)

 - fix dma_mmap_coherent to not cause page attribute mismatches on
   coherent architectures like x86 (me)

* tag 'dma-mapping-5.3-4' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: fix page attributes for dma_mmap_*
  dma-direct: don't truncate dma_required_mask to bus addressing capabilities
  dma-direct: fix DMA_ATTR_NO_KERNEL_MAPPING
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull dma-mapping fixes from Christoph Hellwig:

 - fix the handling of the bus_dma_mask in dma_get_required_mask, which
   caused a regression in this merge window (Lucas Stach)

 - fix a regression in the handling of DMA_ATTR_NO_KERNEL_MAPPING (me)

 - fix dma_mmap_coherent to not cause page attribute mismatches on
   coherent architectures like x86 (me)

* tag 'dma-mapping-5.3-4' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: fix page attributes for dma_mmap_*
  dma-direct: don't truncate dma_required_mask to bus addressing capabilities
  dma-direct: fix DMA_ATTR_NO_KERNEL_MAPPING
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "mm, thp: restore node-local hugepage allocations"</title>
<updated>2019-08-13T23:06:52+00:00</updated>
<author>
<name>Andrea Arcangeli</name>
<email>aarcange@redhat.com</email>
</author>
<published>2019-08-13T22:37:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a8282608c88e08b1782141026eab61204c1e533f'/>
<id>a8282608c88e08b1782141026eab61204c1e533f</id>
<content type='text'>
This reverts commit 2f0799a0ffc033b ("mm, thp: restore node-local
hugepage allocations").

commit 2f0799a0ffc033b was rightfully applied to avoid the risk of a
severe regression that was reported by the kernel test robot at the end
of the merge window.  Now we understood the regression was a false
positive and was caused by a significant increase in fairness during a
swap trashing benchmark.  So it's safe to re-apply the fix and continue
improving the code from there.  The benchmark that reported the
regression is very useful, but it provides a meaningful result only when
there is no significant alteration in fairness during the workload.  The
removal of __GFP_THISNODE increased fairness.

__GFP_THISNODE cannot be used in the generic page faults path for new
memory allocations under the MPOL_DEFAULT mempolicy, or the allocation
behavior significantly deviates from what the MPOL_DEFAULT semantics are
supposed to be for THP and 4k allocations alike.

Setting THP defrag to "always" or using MADV_HUGEPAGE (with THP defrag
set to "madvise") has never meant to provide an implicit MPOL_BIND on
the "current" node the task is running on, causing swap storms and
providing a much more aggressive behavior than even zone_reclaim_node =
3.

Any workload who could have benefited from __GFP_THISNODE has now to
enable zone_reclaim_mode=1||2||3.  __GFP_THISNODE implicitly provided
the zone_reclaim_mode behavior, but it only did so if THP was enabled:
if THP was disabled, there would have been no chance to get any 4k page
from the current node if the current node was full of pagecache, which
further shows how this __GFP_THISNODE was misplaced in MADV_HUGEPAGE.
MADV_HUGEPAGE has never been intended to provide any zone_reclaim_mode
semantics, in fact the two are orthogonal, zone_reclaim_mode = 1|2|3
must work exactly the same with MADV_HUGEPAGE set or not.

The performance characteristic of memory depends on the hardware
details.  The numbers below are obtained on Naples/EPYC architecture and
the N/A projection extends them to show what we should aim for in the
future as a good THP NUMA locality default.  The benchmark used
exercises random memory seeks (note: the cost of the page faults is not
part of the measurement).

  D0 THP | D0 4k | D1 THP | D1 4k | D2 THP | D2 4k | D3 THP | D3 4k | ...
  0%     | +43%  | +45%   | +106% | +131%  | +224% | N/A    | N/A

D0 means distance zero (i.e.  local memory), D1 means distance one (i.e.
intra socket memory), D2 means distance two (i.e.  inter socket memory),
etc...

For the guest physical memory allocated by qemu and for guest mode
kernel the performance characteristic of RAM is more complex and an
ideal default could be:

  D0 THP | D1 THP | D0 4k | D2 THP | D1 4k | D3 THP | D2 4k | D3 4k | ...
  0%     | +58%   | +101% | N/A    | +222% | N/A    | N/A   | N/A

NOTE: the N/A are projections and haven't been measured yet, the
measurement in this case is done on a 1950x with only two NUMA nodes.
The THP case here means THP was used both in the host and in the guest.

After applying this commit the THP NUMA locality order that we'll get
out of MADV_HUGEPAGE is this:

  D0 THP | D1 THP | D2 THP | D3 THP | ... | D0 4k | D1 4k | D2 4k | D3 4k | ...

Before this commit it was:

  D0 THP | D0 4k | D1 4k | D2 4k | D3 4k | ...

Even if we ignore the breakage of large workloads that can't fit in a
single node that the __GFP_THISNODE implicit "current node" mbind
caused, the THP NUMA locality order provided by __GFP_THISNODE was still
not the one we shall aim for in the long term (i.e.  the first one at
the top).

After this commit is applied, we can introduce a new allocator multi
order API and to replace those two alloc_pages_vmas calls in the page
fault path, with a single multi order call:

        unsigned int order = (1 &lt;&lt; HPAGE_PMD_ORDER) | (1 &lt;&lt; 0);
        page = alloc_pages_multi_order(..., &amp;order);
        if (!page)
        	goto out;
        if (!(order &amp; (1 &lt;&lt; 0))) {
        	VM_WARN_ON(order != 1 &lt;&lt; HPAGE_PMD_ORDER);
        	/* THP fault */
        } else {
        	VM_WARN_ON(order != 1 &lt;&lt; 0);
        	/* 4k fallback */
        }

The page allocator logic has to be altered so that when it fails on any
zone with order 9, it has to try again with a order 0 before falling
back to the next zone in the zonelist.

After that we need to do more measurements and evaluate if adding an
opt-in feature for guest mode is worth it, to swap "DN 4k | DN+1 THP"
with "DN+1 THP | DN 4k" at every NUMA distance crossing.

Link: http://lkml.kernel.org/r/20190503223146.2312-3-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Acked-by: Mel Gorman &lt;mgorman@suse.de&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Zi Yan &lt;zi.yan@cs.rutgers.edu&gt;
Cc: Stefan Priebe - Profihost AG &lt;s.priebe@profihost.ag&gt;
Cc: "Kirill A. Shutemov" &lt;kirill@shutemov.name&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts commit 2f0799a0ffc033b ("mm, thp: restore node-local
hugepage allocations").

commit 2f0799a0ffc033b was rightfully applied to avoid the risk of a
severe regression that was reported by the kernel test robot at the end
of the merge window.  Now we understood the regression was a false
positive and was caused by a significant increase in fairness during a
swap trashing benchmark.  So it's safe to re-apply the fix and continue
improving the code from there.  The benchmark that reported the
regression is very useful, but it provides a meaningful result only when
there is no significant alteration in fairness during the workload.  The
removal of __GFP_THISNODE increased fairness.

__GFP_THISNODE cannot be used in the generic page faults path for new
memory allocations under the MPOL_DEFAULT mempolicy, or the allocation
behavior significantly deviates from what the MPOL_DEFAULT semantics are
supposed to be for THP and 4k allocations alike.

Setting THP defrag to "always" or using MADV_HUGEPAGE (with THP defrag
set to "madvise") has never meant to provide an implicit MPOL_BIND on
the "current" node the task is running on, causing swap storms and
providing a much more aggressive behavior than even zone_reclaim_node =
3.

Any workload who could have benefited from __GFP_THISNODE has now to
enable zone_reclaim_mode=1||2||3.  __GFP_THISNODE implicitly provided
the zone_reclaim_mode behavior, but it only did so if THP was enabled:
if THP was disabled, there would have been no chance to get any 4k page
from the current node if the current node was full of pagecache, which
further shows how this __GFP_THISNODE was misplaced in MADV_HUGEPAGE.
MADV_HUGEPAGE has never been intended to provide any zone_reclaim_mode
semantics, in fact the two are orthogonal, zone_reclaim_mode = 1|2|3
must work exactly the same with MADV_HUGEPAGE set or not.

The performance characteristic of memory depends on the hardware
details.  The numbers below are obtained on Naples/EPYC architecture and
the N/A projection extends them to show what we should aim for in the
future as a good THP NUMA locality default.  The benchmark used
exercises random memory seeks (note: the cost of the page faults is not
part of the measurement).

  D0 THP | D0 4k | D1 THP | D1 4k | D2 THP | D2 4k | D3 THP | D3 4k | ...
  0%     | +43%  | +45%   | +106% | +131%  | +224% | N/A    | N/A

D0 means distance zero (i.e.  local memory), D1 means distance one (i.e.
intra socket memory), D2 means distance two (i.e.  inter socket memory),
etc...

For the guest physical memory allocated by qemu and for guest mode
kernel the performance characteristic of RAM is more complex and an
ideal default could be:

  D0 THP | D1 THP | D0 4k | D2 THP | D1 4k | D3 THP | D2 4k | D3 4k | ...
  0%     | +58%   | +101% | N/A    | +222% | N/A    | N/A   | N/A

NOTE: the N/A are projections and haven't been measured yet, the
measurement in this case is done on a 1950x with only two NUMA nodes.
The THP case here means THP was used both in the host and in the guest.

After applying this commit the THP NUMA locality order that we'll get
out of MADV_HUGEPAGE is this:

  D0 THP | D1 THP | D2 THP | D3 THP | ... | D0 4k | D1 4k | D2 4k | D3 4k | ...

Before this commit it was:

  D0 THP | D0 4k | D1 4k | D2 4k | D3 4k | ...

Even if we ignore the breakage of large workloads that can't fit in a
single node that the __GFP_THISNODE implicit "current node" mbind
caused, the THP NUMA locality order provided by __GFP_THISNODE was still
not the one we shall aim for in the long term (i.e.  the first one at
the top).

After this commit is applied, we can introduce a new allocator multi
order API and to replace those two alloc_pages_vmas calls in the page
fault path, with a single multi order call:

        unsigned int order = (1 &lt;&lt; HPAGE_PMD_ORDER) | (1 &lt;&lt; 0);
        page = alloc_pages_multi_order(..., &amp;order);
        if (!page)
        	goto out;
        if (!(order &amp; (1 &lt;&lt; 0))) {
        	VM_WARN_ON(order != 1 &lt;&lt; HPAGE_PMD_ORDER);
        	/* THP fault */
        } else {
        	VM_WARN_ON(order != 1 &lt;&lt; 0);
        	/* 4k fallback */
        }

The page allocator logic has to be altered so that when it fails on any
zone with order 9, it has to try again with a order 0 before falling
back to the next zone in the zonelist.

After that we need to do more measurements and evaluate if adding an
opt-in feature for guest mode is worth it, to swap "DN 4k | DN+1 THP"
with "DN+1 THP | DN 4k" at every NUMA distance crossing.

Link: http://lkml.kernel.org/r/20190503223146.2312-3-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Acked-by: Mel Gorman &lt;mgorman@suse.de&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Zi Yan &lt;zi.yan@cs.rutgers.edu&gt;
Cc: Stefan Priebe - Profihost AG &lt;s.priebe@profihost.ag&gt;
Cc: "Kirill A. Shutemov" &lt;kirill@shutemov.name&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "Revert "mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask""</title>
<updated>2019-08-13T23:06:52+00:00</updated>
<author>
<name>Andrea Arcangeli</name>
<email>aarcange@redhat.com</email>
</author>
<published>2019-08-13T22:37:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=92717d429b38e4f9f934eed7e605cc42858f1839'/>
<id>92717d429b38e4f9f934eed7e605cc42858f1839</id>
<content type='text'>
Patch series "reapply: relax __GFP_THISNODE for MADV_HUGEPAGE mappings".

The fixes for what was originally reported as "pathological THP
behavior" we rightfully reverted to be sure not to introduced
regressions at end of a merge window after a severe regression report
from the kernel bot.  We can safely re-apply them now that we had time
to analyze the problem.

The mm process worked fine, because the good fixes were eventually
committed upstream without excessive delay.

The regression reported by the kernel bot however forced us to revert
the good fixes to be sure not to introduce regressions and to give us
the time to analyze the issue further.  The silver lining is that this
extra time allowed to think more at this issue and also plan for a
future direction to improve things further in terms of THP NUMA
locality.

This patch (of 2):

This reverts commit 356ff8a9a78fb35d ("Revert "mm, thp: consolidate THP
gfp handling into alloc_hugepage_direct_gfpmask").  So it reapplies
89c83fb539f954 ("mm, thp: consolidate THP gfp handling into
alloc_hugepage_direct_gfpmask").

Consolidation of the THP allocation flags at the same place was meant to
be a clean up to easier handle otherwise scattered code which is
imposing a maintenance burden.  There were no real problems observed
with the gfp mask consolidation but the reversion was rushed through
without a larger consensus regardless.

This patch brings the consolidation back because this should make the
long term maintainability easier as well as it should allow future
changes to be less error prone.

[mhocko@kernel.org: changelog additions]
Link: http://lkml.kernel.org/r/20190503223146.2312-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Zi Yan &lt;zi.yan@cs.rutgers.edu&gt;
Cc: Stefan Priebe - Profihost AG &lt;s.priebe@profihost.ag&gt;
Cc: "Kirill A. Shutemov" &lt;kirill@shutemov.name&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Patch series "reapply: relax __GFP_THISNODE for MADV_HUGEPAGE mappings".

The fixes for what was originally reported as "pathological THP
behavior" we rightfully reverted to be sure not to introduced
regressions at end of a merge window after a severe regression report
from the kernel bot.  We can safely re-apply them now that we had time
to analyze the problem.

The mm process worked fine, because the good fixes were eventually
committed upstream without excessive delay.

The regression reported by the kernel bot however forced us to revert
the good fixes to be sure not to introduce regressions and to give us
the time to analyze the issue further.  The silver lining is that this
extra time allowed to think more at this issue and also plan for a
future direction to improve things further in terms of THP NUMA
locality.

This patch (of 2):

This reverts commit 356ff8a9a78fb35d ("Revert "mm, thp: consolidate THP
gfp handling into alloc_hugepage_direct_gfpmask").  So it reapplies
89c83fb539f954 ("mm, thp: consolidate THP gfp handling into
alloc_hugepage_direct_gfpmask").

Consolidation of the THP allocation flags at the same place was meant to
be a clean up to easier handle otherwise scattered code which is
imposing a maintenance burden.  There were no real problems observed
with the gfp mask consolidation but the reversion was rushed through
without a larger consensus regardless.

This patch brings the consolidation back because this should make the
long term maintainability easier as well as it should allow future
changes to be less error prone.

[mhocko@kernel.org: changelog additions]
Link: http://lkml.kernel.org/r/20190503223146.2312-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Zi Yan &lt;zi.yan@cs.rutgers.edu&gt;
Cc: Stefan Priebe - Profihost AG &lt;s.priebe@profihost.ag&gt;
Cc: "Kirill A. Shutemov" &lt;kirill@shutemov.name&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm: workingset: fix vmstat counters for shadow nodes</title>
<updated>2019-08-13T23:06:52+00:00</updated>
<author>
<name>Roman Gushchin</name>
<email>guro@fb.com</email>
</author>
<published>2019-08-13T22:37:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ec9f02384f6053f2a5417e82b65078edc5364a8d'/>
<id>ec9f02384f6053f2a5417e82b65078edc5364a8d</id>
<content type='text'>
Memcg counters for shadow nodes are broken because the memcg pointer is
obtained in a wrong way. The following approach is used:
        virt_to_page(xa_node)-&gt;mem_cgroup

Since commit 4d96ba353075 ("mm: memcg/slab: stop setting
page-&gt;mem_cgroup pointer for slab pages") page-&gt;mem_cgroup pointer isn't
set for slab pages, so memcg_from_slab_page() should be used instead.

Also I doubt that it ever worked correctly: virt_to_head_page() should
be used instead of virt_to_page().  Otherwise objects residing on tail
pages are not accounted, because only the head page contains a valid
mem_cgroup pointer.  That was a case since the introduction of these
counters by the commit 68d48e6a2df5 ("mm: workingset: add vmstat counter
for shadow nodes").

Link: http://lkml.kernel.org/r/20190801233532.138743-1-guro@fb.com
Fixes: 4d96ba353075 ("mm: memcg/slab: stop setting page-&gt;mem_cgroup pointer for slab pages")
Signed-off-by: Roman Gushchin &lt;guro@fb.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Vladimir Davydov &lt;vdavydov.dev@gmail.com&gt;
Cc: Shakeel Butt &lt;shakeelb@google.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Memcg counters for shadow nodes are broken because the memcg pointer is
obtained in a wrong way. The following approach is used:
        virt_to_page(xa_node)-&gt;mem_cgroup

Since commit 4d96ba353075 ("mm: memcg/slab: stop setting
page-&gt;mem_cgroup pointer for slab pages") page-&gt;mem_cgroup pointer isn't
set for slab pages, so memcg_from_slab_page() should be used instead.

Also I doubt that it ever worked correctly: virt_to_head_page() should
be used instead of virt_to_page().  Otherwise objects residing on tail
pages are not accounted, because only the head page contains a valid
mem_cgroup pointer.  That was a case since the introduction of these
counters by the commit 68d48e6a2df5 ("mm: workingset: add vmstat counter
for shadow nodes").

Link: http://lkml.kernel.org/r/20190801233532.138743-1-guro@fb.com
Fixes: 4d96ba353075 ("mm: memcg/slab: stop setting page-&gt;mem_cgroup pointer for slab pages")
Signed-off-by: Roman Gushchin &lt;guro@fb.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Vladimir Davydov &lt;vdavydov.dev@gmail.com&gt;
Cc: Shakeel Butt &lt;shakeelb@google.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm: document zone device struct page field usage</title>
<updated>2019-08-13T23:06:52+00:00</updated>
<author>
<name>Ralph Campbell</name>
<email>rcampbell@nvidia.com</email>
</author>
<published>2019-08-13T22:37:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=76470ccd62f18bfa0954bec10f2329339f793914'/>
<id>76470ccd62f18bfa0954bec10f2329339f793914</id>
<content type='text'>
Patch series "mm/hmm: fixes for device private page migration", v3.

Testing the latest linux git tree turned up a few bugs with page
migration to and from ZONE_DEVICE private and anonymous pages.
Hopefully it clarifies how ZONE_DEVICE private struct page uses the same
mapping and index fields from the source anonymous page mapping.

This patch (of 3):

Struct page for ZONE_DEVICE private pages uses the page-&gt;mapping and and
page-&gt;index fields while the source anonymous pages are migrated to
device private memory.  This is so rmap_walk() can find the page when
migrating the ZONE_DEVICE private page back to system memory.
ZONE_DEVICE pmem backed fsdax pages also use the page-&gt;mapping and
page-&gt;index fields when files are mapped into a process address space.

Add comments to struct page and remove the unused "_zd_pad_1" field to
make this more clear.

Link: http://lkml.kernel.org/r/20190724232700.23327-2-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell &lt;rcampbell@nvidia.com&gt;
Reviewed-by: John Hubbard &lt;jhubbard@nvidia.com&gt;
Cc: Matthew Wilcox &lt;willy@infradead.org&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Christoph Lameter &lt;cl@linux.com&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: Jérôme Glisse &lt;jglisse@redhat.com&gt;
Cc: "Kirill A . Shutemov" &lt;kirill.shutemov@linux.intel.com&gt;
Cc: Lai Jiangshan &lt;jiangshanlai@gmail.com&gt;
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Cc: Pekka Enberg &lt;penberg@kernel.org&gt;
Cc: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Cc: Andrey Ryabinin &lt;aryabinin@virtuozzo.com&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Patch series "mm/hmm: fixes for device private page migration", v3.

Testing the latest linux git tree turned up a few bugs with page
migration to and from ZONE_DEVICE private and anonymous pages.
Hopefully it clarifies how ZONE_DEVICE private struct page uses the same
mapping and index fields from the source anonymous page mapping.

This patch (of 3):

Struct page for ZONE_DEVICE private pages uses the page-&gt;mapping and and
page-&gt;index fields while the source anonymous pages are migrated to
device private memory.  This is so rmap_walk() can find the page when
migrating the ZONE_DEVICE private page back to system memory.
ZONE_DEVICE pmem backed fsdax pages also use the page-&gt;mapping and
page-&gt;index fields when files are mapped into a process address space.

Add comments to struct page and remove the unused "_zd_pad_1" field to
make this more clear.

Link: http://lkml.kernel.org/r/20190724232700.23327-2-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell &lt;rcampbell@nvidia.com&gt;
Reviewed-by: John Hubbard &lt;jhubbard@nvidia.com&gt;
Cc: Matthew Wilcox &lt;willy@infradead.org&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Christoph Lameter &lt;cl@linux.com&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: Jérôme Glisse &lt;jglisse@redhat.com&gt;
Cc: "Kirill A . Shutemov" &lt;kirill.shutemov@linux.intel.com&gt;
Cc: Lai Jiangshan &lt;jiangshanlai@gmail.com&gt;
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Cc: Pekka Enberg &lt;penberg@kernel.org&gt;
Cc: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Cc: Andrey Ryabinin &lt;aryabinin@virtuozzo.com&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
