<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/Documentation/admin-guide, branch v4.18-rc7</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>docs: kernel-parameters.txt: document xhci-hcd.quirks parameter</title>
<updated>2018-07-06T14:28:30+00:00</updated>
<author>
<name>Laurentiu Tudor</name>
<email>laurentiu.tudor@nxp.com</email>
</author>
<published>2018-07-05T13:31:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=c0addc9a5ba88350a3d9365a73290e34dc238b70'/>
<id>c0addc9a5ba88350a3d9365a73290e34dc238b70</id>
<content type='text'>
This parameter introduced several years ago in the XHCI host controller
driver was somehow left undocumented. Add a few lines in the kernel
parameters text.

Signed-off-by: Laurentiu Tudor &lt;laurentiu.tudor@nxp.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This parameter introduced several years ago in the XHCI host controller
driver was somehow left undocumented. Add a few lines in the kernel
parameters text.

Signed-off-by: Laurentiu Tudor &lt;laurentiu.tudor@nxp.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Documentation: intel_pstate: Describe hwp_dynamic_boost sysfs knob</title>
<updated>2018-06-27T11:02:06+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2018-06-26T15:20:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=649f53a3e4cf6873741673b9271275e484c56194'/>
<id>649f53a3e4cf6873741673b9271275e484c56194</id>
<content type='text'>
Document the recently introduced hwp_dynamic_boost sysfs knob
allowing user space to tell intel_pstate to use iowait boosting
in the active mode with HWP enabled (to improve performance).

Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Acked-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Document the recently introduced hwp_dynamic_boost sysfs knob
allowing user space to tell intel_pstate to use iowait boosting
in the active mode with HWP enabled (to improve performance).

Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Acked-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Documentation: admin-guide: intel_pstate: Fix sysfs path</title>
<updated>2018-06-27T11:02:06+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2018-06-26T10:09:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=9e421b8fffb92bfd1c274f1deae611a6ab99d8a7'/>
<id>9e421b8fffb92bfd1c274f1deae611a6ab99d8a7</id>
<content type='text'>
Fix an incorrect sysfs path in the intel_pstate admin-guide
documentation.

Fixes: 33fc30b47098 (cpufreq: intel_pstate: Document the current behavior and user interface)
Reported-by: Pawit Pornkitprasan &lt;p.pawit@gmail.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fix an incorrect sysfs path in the intel_pstate admin-guide
documentation.

Fixes: 33fc30b47098 (cpufreq: intel_pstate: Document the current behavior and user interface)
Reported-by: Pawit Pornkitprasan &lt;p.pawit@gmail.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Documentation: intel_pstate: Fix typo</title>
<updated>2018-06-20T22:35:19+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2018-06-20T08:42:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=7a0f9d1eb51ff25d119b48fe7cc6aa0433cd6621'/>
<id>7a0f9d1eb51ff25d119b48fe7cc6aa0433cd6621</id>
<content type='text'>
Fix a typo in the intel_pstate admin-guide documentation.

Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fix a typo in the intel_pstate admin-guide documentation.

Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>kernel-parameters.txt: fix pointers to sound parameters</title>
<updated>2018-06-15T21:10:01+00:00</updated>
<author>
<name>Mauro Carvalho Chehab</name>
<email>mchehab+samsung@kernel.org</email>
</author>
<published>2018-06-14T10:43:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=1ca2c806d85272f5d412910df160d82c2234c0e0'/>
<id>1ca2c806d85272f5d412910df160d82c2234c0e0</id>
<content type='text'>
The alsa parameters file was renamed to alsa-configuration.rst.

With regards to OSS, it got retired as a hole by  at changeset
727dede0ba8a ("sound: Retire OSS"). So, it doesn't make sense
to keep mentioning it at kernel-parameters.txt.

Fixes: 727dede0ba8a ("sound: Retire OSS")
Signed-off-by: Mauro Carvalho Chehab &lt;mchehab+samsung@kernel.org&gt;
Acked-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The alsa parameters file was renamed to alsa-configuration.rst.

With regards to OSS, it got retired as a hole by  at changeset
727dede0ba8a ("sound: Retire OSS"). So, it doesn't make sense
to keep mentioning it at kernel-parameters.txt.

Fixes: 727dede0ba8a ("sound: Retire OSS")
Signed-off-by: Mauro Carvalho Chehab &lt;mchehab+samsung@kernel.org&gt;
Acked-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>docs: Fix some broken references</title>
<updated>2018-06-15T21:10:01+00:00</updated>
<author>
<name>Mauro Carvalho Chehab</name>
<email>mchehab+samsung@kernel.org</email>
</author>
<published>2018-05-08T18:14:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=5fb94e9ca333f0fe1d96de06704a79942b3832c3'/>
<id>5fb94e9ca333f0fe1d96de06704a79942b3832c3</id>
<content type='text'>
As we move stuff around, some doc references are broken. Fix some of
them via this script:
	./scripts/documentation-file-ref-check --fix

Manually checked if the produced result is valid, removing a few
false-positives.

Acked-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Acked-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Acked-by: Stephen Boyd &lt;sboyd@kernel.org&gt;
Acked-by: Charles Keepax &lt;ckeepax@opensource.wolfsonmicro.com&gt;
Acked-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Reviewed-by: Coly Li &lt;colyli@suse.de&gt;
Signed-off-by: Mauro Carvalho Chehab &lt;mchehab+samsung@kernel.org&gt;
Acked-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
As we move stuff around, some doc references are broken. Fix some of
them via this script:
	./scripts/documentation-file-ref-check --fix

Manually checked if the produced result is valid, removing a few
false-positives.

Acked-by: Takashi Iwai &lt;tiwai@suse.de&gt;
Acked-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Acked-by: Stephen Boyd &lt;sboyd@kernel.org&gt;
Acked-by: Charles Keepax &lt;ckeepax@opensource.wolfsonmicro.com&gt;
Acked-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Reviewed-by: Coly Li &lt;colyli@suse.de&gt;
Signed-off-by: Mauro Carvalho Chehab &lt;mchehab+samsung@kernel.org&gt;
Acked-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'apparmor-pr-2018-06-13' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor</title>
<updated>2018-06-14T07:11:28+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-06-14T07:11:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=463f202172c31b9c36278001cabfbad4e12da42e'/>
<id>463f202172c31b9c36278001cabfbad4e12da42e</id>
<content type='text'>
Pull AppArmor updates from John Johansen:
 "Features
   - add support for mapping secids and using secctxes
   - add the ability to get a task's secid
   - add support for audit rule filtering

  Cleanups:
   - multiple typo fixes
   - Convert to use match_string() helper
   - update git and wiki locations in AppArmor docs
   - improve get_buffers macro by using get_cpu_ptr
   - Use an IDR to allocate apparmor secids

  Bug fixes:
   - fix '*seclen' is never less than zero
   - fix mediation of prlimit
   - fix memory leak when deduping profile load
   - fix ptrace read check
   - fix memory leak of rule on error exit path"

* tag 'apparmor-pr-2018-06-13' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor: (21 commits)
  apparmor: fix ptrace read check
  apparmor: fix memory leak when deduping profile load
  apparmor: fix mediation of prlimit
  apparmor: fixup secid map conversion to using IDR
  apparmor: Use an IDR to allocate apparmor secids
  apparmor: Fix memory leak of rule on error exit path
  apparmor: modify audit rule support to support profile stacks
  apparmor: Add support for audit rule filtering
  apparmor: update git and wiki locations in AppArmor docs
  apparmor: Convert to use match_string() helper
  apparmor: improve get_buffers macro by using get_cpu_ptr
  apparmor: fix '*seclen' is never less than zero
  apparmor: fix typo "preconfinement"
  apparmor: fix typo "independent"
  apparmor: fix typo "traverse"
  apparmor: fix typo "type"
  apparmor: fix typo "replace"
  apparmor: fix typo "comparison"
  apparmor: fix typo "loosen"
  apparmor: add the ability to get a task's secid
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull AppArmor updates from John Johansen:
 "Features
   - add support for mapping secids and using secctxes
   - add the ability to get a task's secid
   - add support for audit rule filtering

  Cleanups:
   - multiple typo fixes
   - Convert to use match_string() helper
   - update git and wiki locations in AppArmor docs
   - improve get_buffers macro by using get_cpu_ptr
   - Use an IDR to allocate apparmor secids

  Bug fixes:
   - fix '*seclen' is never less than zero
   - fix mediation of prlimit
   - fix memory leak when deduping profile load
   - fix ptrace read check
   - fix memory leak of rule on error exit path"

* tag 'apparmor-pr-2018-06-13' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor: (21 commits)
  apparmor: fix ptrace read check
  apparmor: fix memory leak when deduping profile load
  apparmor: fix mediation of prlimit
  apparmor: fixup secid map conversion to using IDR
  apparmor: Use an IDR to allocate apparmor secids
  apparmor: Fix memory leak of rule on error exit path
  apparmor: modify audit rule support to support profile stacks
  apparmor: Add support for audit rule filtering
  apparmor: update git and wiki locations in AppArmor docs
  apparmor: Convert to use match_string() helper
  apparmor: improve get_buffers macro by using get_cpu_ptr
  apparmor: fix '*seclen' is never less than zero
  apparmor: fix typo "preconfinement"
  apparmor: fix typo "independent"
  apparmor: fix typo "traverse"
  apparmor: fix typo "type"
  apparmor: fix typo "replace"
  apparmor: fix typo "comparison"
  apparmor: fix typo "loosen"
  apparmor: add the ability to get a task's secid
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux</title>
<updated>2018-06-08T18:10:58+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-06-08T18:10:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=410feb75de245664d66bc05ab2e2412751d10acf'/>
<id>410feb75de245664d66bc05ab2e2412751d10acf</id>
<content type='text'>
Pull arm64 updates from Catalin Marinas:
 "Apart from the core arm64 and perf changes, the Spectre v4 mitigation
  touches the arm KVM code and the ACPI PPTT support touches drivers/
  (acpi and cacheinfo). I should have the maintainers' acks in place.

  Summary:

   - Spectre v4 mitigation (Speculative Store Bypass Disable) support
     for arm64 using SMC firmware call to set a hardware chicken bit

   - ACPI PPTT (Processor Properties Topology Table) parsing support and
     enable the feature for arm64

   - Report signal frame size to user via auxv (AT_MINSIGSTKSZ). The
     primary motivation is Scalable Vector Extensions which requires
     more space on the signal frame than the currently defined
     MINSIGSTKSZ

   - ARM perf patches: allow building arm-cci as module, demote
     dev_warn() to dev_dbg() in arm-ccn event_init(), miscellaneous
     cleanups

   - cmpwait() WFE optimisation to avoid some spurious wakeups

   - L1_CACHE_BYTES reverted back to 64 (for performance reasons that
     have to do with some network allocations) while keeping
     ARCH_DMA_MINALIGN to 128. cache_line_size() returns the actual
     hardware Cache Writeback Granule

   - Turn LSE atomics on by default in Kconfig

   - Kernel fault reporting tidying

   - Some #include and miscellaneous cleanups"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (53 commits)
  arm64: Fix syscall restarting around signal suppressed by tracer
  arm64: topology: Avoid checking numa mask for scheduler MC selection
  ACPI / PPTT: fix build when CONFIG_ACPI_PPTT is not enabled
  arm64: cpu_errata: include required headers
  arm64: KVM: Move VCPU_WORKAROUND_2_FLAG macros to the top of the file
  arm64: signal: Report signal frame size to userspace via auxv
  arm64/sve: Thin out initialisation sanity-checks for sve_max_vl
  arm64: KVM: Add ARCH_WORKAROUND_2 discovery through ARCH_FEATURES_FUNC_ID
  arm64: KVM: Handle guest's ARCH_WORKAROUND_2 requests
  arm64: KVM: Add ARCH_WORKAROUND_2 support for guests
  arm64: KVM: Add HYP per-cpu accessors
  arm64: ssbd: Add prctl interface for per-thread mitigation
  arm64: ssbd: Introduce thread flag to control userspace mitigation
  arm64: ssbd: Restore mitigation status on CPU resume
  arm64: ssbd: Skip apply_ssbd if not using dynamic mitigation
  arm64: ssbd: Add global mitigation state accessor
  arm64: Add 'ssbd' command-line option
  arm64: Add ARCH_WORKAROUND_2 probing
  arm64: Add per-cpu infrastructure to call ARCH_WORKAROUND_2
  arm64: Call ARCH_WORKAROUND_2 on transitions between EL0 and EL1
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull arm64 updates from Catalin Marinas:
 "Apart from the core arm64 and perf changes, the Spectre v4 mitigation
  touches the arm KVM code and the ACPI PPTT support touches drivers/
  (acpi and cacheinfo). I should have the maintainers' acks in place.

  Summary:

   - Spectre v4 mitigation (Speculative Store Bypass Disable) support
     for arm64 using SMC firmware call to set a hardware chicken bit

   - ACPI PPTT (Processor Properties Topology Table) parsing support and
     enable the feature for arm64

   - Report signal frame size to user via auxv (AT_MINSIGSTKSZ). The
     primary motivation is Scalable Vector Extensions which requires
     more space on the signal frame than the currently defined
     MINSIGSTKSZ

   - ARM perf patches: allow building arm-cci as module, demote
     dev_warn() to dev_dbg() in arm-ccn event_init(), miscellaneous
     cleanups

   - cmpwait() WFE optimisation to avoid some spurious wakeups

   - L1_CACHE_BYTES reverted back to 64 (for performance reasons that
     have to do with some network allocations) while keeping
     ARCH_DMA_MINALIGN to 128. cache_line_size() returns the actual
     hardware Cache Writeback Granule

   - Turn LSE atomics on by default in Kconfig

   - Kernel fault reporting tidying

   - Some #include and miscellaneous cleanups"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (53 commits)
  arm64: Fix syscall restarting around signal suppressed by tracer
  arm64: topology: Avoid checking numa mask for scheduler MC selection
  ACPI / PPTT: fix build when CONFIG_ACPI_PPTT is not enabled
  arm64: cpu_errata: include required headers
  arm64: KVM: Move VCPU_WORKAROUND_2_FLAG macros to the top of the file
  arm64: signal: Report signal frame size to userspace via auxv
  arm64/sve: Thin out initialisation sanity-checks for sve_max_vl
  arm64: KVM: Add ARCH_WORKAROUND_2 discovery through ARCH_FEATURES_FUNC_ID
  arm64: KVM: Handle guest's ARCH_WORKAROUND_2 requests
  arm64: KVM: Add ARCH_WORKAROUND_2 support for guests
  arm64: KVM: Add HYP per-cpu accessors
  arm64: ssbd: Add prctl interface for per-thread mitigation
  arm64: ssbd: Introduce thread flag to control userspace mitigation
  arm64: ssbd: Restore mitigation status on CPU resume
  arm64: ssbd: Skip apply_ssbd if not using dynamic mitigation
  arm64: ssbd: Add global mitigation state accessor
  arm64: Add 'ssbd' command-line option
  arm64: Add ARCH_WORKAROUND_2 probing
  arm64: Add per-cpu infrastructure to call ARCH_WORKAROUND_2
  arm64: Call ARCH_WORKAROUND_2 on transitions between EL0 and EL1
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'akpm' (patches from Andrew)</title>
<updated>2018-06-08T01:39:37+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-06-08T01:39:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=68abbe729567cef128b2c2141f2ed2567f3b8372'/>
<id>68abbe729567cef128b2c2141f2ed2567f3b8372</id>
<content type='text'>
Merge updates from Andrew Morton:

 - a few misc things

 - ocfs2 updates

 - v9fs updates

 - MM

 - procfs updates

 - lib/ updates

 - autofs updates

* emailed patches from Andrew Morton &lt;akpm@linux-foundation.org&gt;: (118 commits)
  autofs: small cleanup in autofs_getpath()
  autofs: clean up includes
  autofs: comment on selinux changes needed for module autoload
  autofs: update MAINTAINERS entry for autofs
  autofs: use autofs instead of autofs4 in documentation
  autofs: rename autofs documentation files
  autofs: create autofs Kconfig and Makefile
  autofs: delete fs/autofs4 source files
  autofs: update fs/autofs4/Makefile
  autofs: update fs/autofs4/Kconfig
  autofs: copy autofs4 to autofs
  autofs4: use autofs instead of autofs4 everywhere
  autofs4: merge auto_fs.h and auto_fs4.h
  fs/binfmt_misc.c: do not allow offset overflow
  checkpatch: improve patch recognition
  lib/ucs2_string.c: add MODULE_LICENSE()
  lib/mpi: headers cleanup
  lib/percpu_ida.c: use _irqsave() instead of local_irq_save() + spin_lock
  lib/idr.c: remove simple_ida_lock
  lib/bitmap.c: micro-optimization for __bitmap_complement()
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Merge updates from Andrew Morton:

 - a few misc things

 - ocfs2 updates

 - v9fs updates

 - MM

 - procfs updates

 - lib/ updates

 - autofs updates

* emailed patches from Andrew Morton &lt;akpm@linux-foundation.org&gt;: (118 commits)
  autofs: small cleanup in autofs_getpath()
  autofs: clean up includes
  autofs: comment on selinux changes needed for module autoload
  autofs: update MAINTAINERS entry for autofs
  autofs: use autofs instead of autofs4 in documentation
  autofs: rename autofs documentation files
  autofs: create autofs Kconfig and Makefile
  autofs: delete fs/autofs4 source files
  autofs: update fs/autofs4/Makefile
  autofs: update fs/autofs4/Kconfig
  autofs: copy autofs4 to autofs
  autofs4: use autofs instead of autofs4 everywhere
  autofs4: merge auto_fs.h and auto_fs4.h
  fs/binfmt_misc.c: do not allow offset overflow
  checkpatch: improve patch recognition
  lib/ucs2_string.c: add MODULE_LICENSE()
  lib/mpi: headers cleanup
  lib/percpu_ida.c: use _irqsave() instead of local_irq_save() + spin_lock
  lib/idr.c: remove simple_ida_lock
  lib/bitmap.c: micro-optimization for __bitmap_complement()
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>mm: memcg: allow lowering memory.swap.max below the current usage</title>
<updated>2018-06-08T00:34:37+00:00</updated>
<author>
<name>Tejun Heo</name>
<email>tj@kernel.org</email>
</author>
<published>2018-06-08T00:09:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=be09102b4190561b67e3809b07a7fd29c9774152'/>
<id>be09102b4190561b67e3809b07a7fd29c9774152</id>
<content type='text'>
Currently an attempt to set swap.max into a value lower than the actual
swap usage fails, which causes configuration problems as there's no way
of lowering the configuration below the current usage short of turning
off swap entirely.  This makes swap.max difficult to use and allows
delegatees to lock the delegator out of reducing swap allocation.

This patch updates swap_max_write() so that the limit can be lowered
below the current usage.  It doesn't implement active reclaiming of swap
entries for the following reasons.

* mem_cgroup_swap_full() already tells the swap machinary to
  aggressively reclaim swap entries if the usage is above 50% of
  limit, so simply lowering the limit automatically triggers gradual
  reclaim.

* Forcing back swapped out pages is likely to heavily impact the
  workload and mess up the working set.  Given that swap usually is a
  lot less valuable and less scarce, letting the existing usage
  dissipate over time through the above gradual reclaim and as they're
  falted back in is likely the better behavior.

Link: http://lkml.kernel.org/r/20180523185041.GR1718769@devbig577.frc2.facebook.com
Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Acked-by: Roman Gushchin &lt;guro@fb.com&gt;
Acked-by: Rik van Riel &lt;riel@surriel.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Shaohua Li &lt;shli@fb.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
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<pre>
Currently an attempt to set swap.max into a value lower than the actual
swap usage fails, which causes configuration problems as there's no way
of lowering the configuration below the current usage short of turning
off swap entirely.  This makes swap.max difficult to use and allows
delegatees to lock the delegator out of reducing swap allocation.

This patch updates swap_max_write() so that the limit can be lowered
below the current usage.  It doesn't implement active reclaiming of swap
entries for the following reasons.

* mem_cgroup_swap_full() already tells the swap machinary to
  aggressively reclaim swap entries if the usage is above 50% of
  limit, so simply lowering the limit automatically triggers gradual
  reclaim.

* Forcing back swapped out pages is likely to heavily impact the
  workload and mess up the working set.  Given that swap usually is a
  lot less valuable and less scarce, letting the existing usage
  dissipate over time through the above gradual reclaim and as they're
  falted back in is likely the better behavior.

Link: http://lkml.kernel.org/r/20180523185041.GR1718769@devbig577.frc2.facebook.com
Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Acked-by: Roman Gushchin &lt;guro@fb.com&gt;
Acked-by: Rik van Riel &lt;riel@surriel.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Shaohua Li &lt;shli@fb.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>
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</content>
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