<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/Documentation/admin-guide/sysctl, branch v5.13-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>docs: admin-guide: update description for kernel.modprobe sysctl</title>
<updated>2021-05-15T02:41:32+00:00</updated>
<author>
<name>Rasmus Villemoes</name>
<email>linux@rasmusvillemoes.dk</email>
</author>
<published>2021-05-15T00:27:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f4d3f25aced3b493e57fd4109e2bc86f0831b23e'/>
<id>f4d3f25aced3b493e57fd4109e2bc86f0831b23e</id>
<content type='text'>
When I added CONFIG_MODPROBE_PATH, I neglected to update Documentation/.
It's still true that this defaults to /sbin/modprobe, but now via a level
of indirection.  So document that the kernel might have been built with
something other than /sbin/modprobe as the initial value.

Link: https://lkml.kernel.org/r/20210420125324.1246826-1-linux@rasmusvillemoes.dk
Fixes: 17652f4240f7a ("modules: add CONFIG_MODPROBE_PATH")
Signed-off-by: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Cc: Jonathan Corbet &lt;corbet@lwn.net&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Jessica Yu &lt;jeyu@kernel.org&gt;
Cc: Luis Chamberlain &lt;mcgrof@kernel.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>
When I added CONFIG_MODPROBE_PATH, I neglected to update Documentation/.
It's still true that this defaults to /sbin/modprobe, but now via a level
of indirection.  So document that the kernel might have been built with
something other than /sbin/modprobe as the initial value.

Link: https://lkml.kernel.org/r/20210420125324.1246826-1-linux@rasmusvillemoes.dk
Fixes: 17652f4240f7a ("modules: add CONFIG_MODPROBE_PATH")
Signed-off-by: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Cc: Jonathan Corbet &lt;corbet@lwn.net&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Jessica Yu &lt;jeyu@kernel.org&gt;
Cc: Luis Chamberlain &lt;mcgrof@kernel.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>
<entry>
<title>Merge tag 'powerpc-5.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux</title>
<updated>2021-04-30T19:22:28+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-04-30T19:22:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c70a4be130de333ea079c59da41cc959712bb01c'/>
<id>c70a4be130de333ea079c59da41cc959712bb01c</id>
<content type='text'>
Pull powerpc updates from Michael Ellerman:

 - Enable KFENCE for 32-bit.

 - Implement EBPF for 32-bit.

 - Convert 32-bit to do interrupt entry/exit in C.

 - Convert 64-bit BookE to do interrupt entry/exit in C.

 - Changes to our signal handling code to use user_access_begin/end()
   more extensively.

 - Add support for time namespaces (CONFIG_TIME_NS)

 - A series of fixes that allow us to reenable STRICT_KERNEL_RWX.

 - Other smaller features, fixes &amp; cleanups.

Thanks to Alexey Kardashevskiy, Andreas Schwab, Andrew Donnellan, Aneesh
Kumar K.V, Athira Rajeev, Bhaskar Chowdhury, Bixuan Cui, Cédric Le
Goater, Chen Huang, Chris Packham, Christophe Leroy, Christopher M.
Riedl, Colin Ian King, Dan Carpenter, Daniel Axtens, Daniel Henrique
Barboza, David Gibson, Davidlohr Bueso, Denis Efremov, dingsenjie,
Dmitry Safonov, Dominic DeMarco, Fabiano Rosas, Ganesh Goudar, Geert
Uytterhoeven, Geetika Moolchandani, Greg Kurz, Guenter Roeck, Haren
Myneni, He Ying, Jiapeng Chong, Jordan Niethe, Laurent Dufour, Lee
Jones, Leonardo Bras, Li Huafei, Madhavan Srinivasan, Mahesh Salgaonkar,
Masahiro Yamada, Nathan Chancellor, Nathan Lynch, Nicholas Piggin,
Oliver O'Halloran, Paul Menzel, Pu Lehui, Randy Dunlap, Ravi Bangoria,
Rosen Penev, Russell Currey, Santosh Sivaraj, Sebastian Andrzej Siewior,
Segher Boessenkool, Shivaprasad G Bhat, Srikar Dronamraju, Stephen
Rothwell, Thadeu Lima de Souza Cascardo, Thomas Gleixner, Tony Ambardar,
Tyrel Datwyler, Vaibhav Jain, Vincenzo Frascino, Xiongwei Song, Yang Li,
Yu Kuai, and Zhang Yunkai.

* tag 'powerpc-5.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (302 commits)
  powerpc/signal32: Fix erroneous SIGSEGV on RT signal return
  powerpc: Avoid clang uninitialized warning in __get_user_size_allowed
  powerpc/papr_scm: Mark nvdimm as unarmed if needed during probe
  powerpc/kvm: Fix build error when PPC_MEM_KEYS/PPC_PSERIES=n
  powerpc/kasan: Fix shadow start address with modules
  powerpc/kernel/iommu: Use largepool as a last resort when !largealloc
  powerpc/kernel/iommu: Align size for IOMMU_PAGE_SIZE() to save TCEs
  powerpc/44x: fix spelling mistake in Kconfig "varients" -&gt; "variants"
  powerpc/iommu: Annotate nested lock for lockdep
  powerpc/iommu: Do not immediately panic when failed IOMMU table allocation
  powerpc/iommu: Allocate it_map by vmalloc
  selftests/powerpc: remove unneeded semicolon
  powerpc/64s: remove unneeded semicolon
  powerpc/eeh: remove unneeded semicolon
  powerpc/selftests: Add selftest to test concurrent perf/ptrace events
  powerpc/selftests/perf-hwbreak: Add testcases for 2nd DAWR
  powerpc/selftests/perf-hwbreak: Coalesce event creation code
  powerpc/selftests/ptrace-hwbreak: Add testcases for 2nd DAWR
  powerpc/configs: Add IBMVNIC to some 64-bit configs
  selftests/powerpc: Add uaccess flush test
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull powerpc updates from Michael Ellerman:

 - Enable KFENCE for 32-bit.

 - Implement EBPF for 32-bit.

 - Convert 32-bit to do interrupt entry/exit in C.

 - Convert 64-bit BookE to do interrupt entry/exit in C.

 - Changes to our signal handling code to use user_access_begin/end()
   more extensively.

 - Add support for time namespaces (CONFIG_TIME_NS)

 - A series of fixes that allow us to reenable STRICT_KERNEL_RWX.

 - Other smaller features, fixes &amp; cleanups.

Thanks to Alexey Kardashevskiy, Andreas Schwab, Andrew Donnellan, Aneesh
Kumar K.V, Athira Rajeev, Bhaskar Chowdhury, Bixuan Cui, Cédric Le
Goater, Chen Huang, Chris Packham, Christophe Leroy, Christopher M.
Riedl, Colin Ian King, Dan Carpenter, Daniel Axtens, Daniel Henrique
Barboza, David Gibson, Davidlohr Bueso, Denis Efremov, dingsenjie,
Dmitry Safonov, Dominic DeMarco, Fabiano Rosas, Ganesh Goudar, Geert
Uytterhoeven, Geetika Moolchandani, Greg Kurz, Guenter Roeck, Haren
Myneni, He Ying, Jiapeng Chong, Jordan Niethe, Laurent Dufour, Lee
Jones, Leonardo Bras, Li Huafei, Madhavan Srinivasan, Mahesh Salgaonkar,
Masahiro Yamada, Nathan Chancellor, Nathan Lynch, Nicholas Piggin,
Oliver O'Halloran, Paul Menzel, Pu Lehui, Randy Dunlap, Ravi Bangoria,
Rosen Penev, Russell Currey, Santosh Sivaraj, Sebastian Andrzej Siewior,
Segher Boessenkool, Shivaprasad G Bhat, Srikar Dronamraju, Stephen
Rothwell, Thadeu Lima de Souza Cascardo, Thomas Gleixner, Tony Ambardar,
Tyrel Datwyler, Vaibhav Jain, Vincenzo Frascino, Xiongwei Song, Yang Li,
Yu Kuai, and Zhang Yunkai.

* tag 'powerpc-5.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (302 commits)
  powerpc/signal32: Fix erroneous SIGSEGV on RT signal return
  powerpc: Avoid clang uninitialized warning in __get_user_size_allowed
  powerpc/papr_scm: Mark nvdimm as unarmed if needed during probe
  powerpc/kvm: Fix build error when PPC_MEM_KEYS/PPC_PSERIES=n
  powerpc/kasan: Fix shadow start address with modules
  powerpc/kernel/iommu: Use largepool as a last resort when !largealloc
  powerpc/kernel/iommu: Align size for IOMMU_PAGE_SIZE() to save TCEs
  powerpc/44x: fix spelling mistake in Kconfig "varients" -&gt; "variants"
  powerpc/iommu: Annotate nested lock for lockdep
  powerpc/iommu: Do not immediately panic when failed IOMMU table allocation
  powerpc/iommu: Allocate it_map by vmalloc
  selftests/powerpc: remove unneeded semicolon
  powerpc/64s: remove unneeded semicolon
  powerpc/eeh: remove unneeded semicolon
  powerpc/selftests: Add selftest to test concurrent perf/ptrace events
  powerpc/selftests/perf-hwbreak: Add testcases for 2nd DAWR
  powerpc/selftests/perf-hwbreak: Coalesce event creation code
  powerpc/selftests/ptrace-hwbreak: Add testcases for 2nd DAWR
  powerpc/configs: Add IBMVNIC to some 64-bit configs
  selftests/powerpc: Add uaccess flush test
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>powerpc/bpf: Implement extended BPF on PPC32</title>
<updated>2021-04-03T10:22:21+00:00</updated>
<author>
<name>Christophe Leroy</name>
<email>christophe.leroy@csgroup.eu</email>
</author>
<published>2021-03-22T16:37:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=51c66ad849a703d9bbfd7704c941827aed0fd9fd'/>
<id>51c66ad849a703d9bbfd7704c941827aed0fd9fd</id>
<content type='text'>
Implement Extended Berkeley Packet Filter on Powerpc 32

Test result with test_bpf module:

	test_bpf: Summary: 378 PASSED, 0 FAILED, [354/366 JIT'ed]

Registers mapping:

	[BPF_REG_0] = r11-r12
	/* function arguments */
	[BPF_REG_1] = r3-r4
	[BPF_REG_2] = r5-r6
	[BPF_REG_3] = r7-r8
	[BPF_REG_4] = r9-r10
	[BPF_REG_5] = r21-r22 (Args 9 and 10 come in via the stack)
	/* non volatile registers */
	[BPF_REG_6] = r23-r24
	[BPF_REG_7] = r25-r26
	[BPF_REG_8] = r27-r28
	[BPF_REG_9] = r29-r30
	/* frame pointer aka BPF_REG_10 */
	[BPF_REG_FP] = r17-r18
	/* eBPF jit internal registers */
	[BPF_REG_AX] = r19-r20
	[TMP_REG] = r31

As PPC32 doesn't have a redzone in the stack, a stack frame must always
be set in order to host at least the tail count counter.

The stack frame remains for tail calls, it is set by the first callee
and freed by the last callee.

r0 is used as temporary register as much as possible. It is referenced
directly in the code in order to avoid misusing it, because some
instructions interpret it as value 0 instead of register r0
(ex: addi, addis, stw, lwz, ...)

The following operations are not implemented:

		case BPF_ALU64 | BPF_DIV | BPF_X: /* dst /= src */
		case BPF_ALU64 | BPF_MOD | BPF_X: /* dst %= src */
		case BPF_STX | BPF_XADD | BPF_DW: /* *(u64 *)(dst + off) += src */

The following operations are only implemented for power of two constants:

		case BPF_ALU64 | BPF_MOD | BPF_K: /* dst %= imm */
		case BPF_ALU64 | BPF_DIV | BPF_K: /* dst /= imm */

Signed-off-by: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/61d8b149176ddf99e7d5cef0b6dc1598583ca202.1616430991.git.christophe.leroy@csgroup.eu
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Implement Extended Berkeley Packet Filter on Powerpc 32

Test result with test_bpf module:

	test_bpf: Summary: 378 PASSED, 0 FAILED, [354/366 JIT'ed]

Registers mapping:

	[BPF_REG_0] = r11-r12
	/* function arguments */
	[BPF_REG_1] = r3-r4
	[BPF_REG_2] = r5-r6
	[BPF_REG_3] = r7-r8
	[BPF_REG_4] = r9-r10
	[BPF_REG_5] = r21-r22 (Args 9 and 10 come in via the stack)
	/* non volatile registers */
	[BPF_REG_6] = r23-r24
	[BPF_REG_7] = r25-r26
	[BPF_REG_8] = r27-r28
	[BPF_REG_9] = r29-r30
	/* frame pointer aka BPF_REG_10 */
	[BPF_REG_FP] = r17-r18
	/* eBPF jit internal registers */
	[BPF_REG_AX] = r19-r20
	[TMP_REG] = r31

As PPC32 doesn't have a redzone in the stack, a stack frame must always
be set in order to host at least the tail count counter.

The stack frame remains for tail calls, it is set by the first callee
and freed by the last callee.

r0 is used as temporary register as much as possible. It is referenced
directly in the code in order to avoid misusing it, because some
instructions interpret it as value 0 instead of register r0
(ex: addi, addis, stw, lwz, ...)

The following operations are not implemented:

		case BPF_ALU64 | BPF_DIV | BPF_X: /* dst /= src */
		case BPF_ALU64 | BPF_MOD | BPF_X: /* dst %= src */
		case BPF_STX | BPF_XADD | BPF_DW: /* *(u64 *)(dst + off) += src */

The following operations are only implemented for power of two constants:

		case BPF_ALU64 | BPF_MOD | BPF_K: /* dst %= imm */
		case BPF_ALU64 | BPF_DIV | BPF_K: /* dst /= imm */

Signed-off-by: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/r/61d8b149176ddf99e7d5cef0b6dc1598583ca202.1616430991.git.christophe.leroy@csgroup.eu
</pre>
</div>
</content>
</entry>
<entry>
<title>net: change netdev_unregister_timeout_secs min value to 1</title>
<updated>2021-03-26T00:24:06+00:00</updated>
<author>
<name>Dmitry Vyukov</name>
<email>dvyukov@google.com</email>
</author>
<published>2021-03-25T14:52:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6c996e19949b34d7edebed4f6b0511145c036404'/>
<id>6c996e19949b34d7edebed4f6b0511145c036404</id>
<content type='text'>
netdev_unregister_timeout_secs=0 can lead to printing the
"waiting for dev to become free" message every jiffy.
This is too frequent and unnecessary.
Set the min value to 1 second.

Also fix the merge issue introduced by
"net: make unregister netdev warning timeout configurable":
it changed "refcnt != 1" to "refcnt".

Signed-off-by: Dmitry Vyukov &lt;dvyukov@google.com&gt;
Suggested-by: Eric Dumazet &lt;edumazet@google.com&gt;
Fixes: 5aa3afe107d9 ("net: make unregister netdev warning timeout configurable")
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
netdev_unregister_timeout_secs=0 can lead to printing the
"waiting for dev to become free" message every jiffy.
This is too frequent and unnecessary.
Set the min value to 1 second.

Also fix the merge issue introduced by
"net: make unregister netdev warning timeout configurable":
it changed "refcnt != 1" to "refcnt".

Signed-off-by: Dmitry Vyukov &lt;dvyukov@google.com&gt;
Suggested-by: Eric Dumazet &lt;edumazet@google.com&gt;
Fixes: 5aa3afe107d9 ("net: make unregister netdev warning timeout configurable")
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: make unregister netdev warning timeout configurable</title>
<updated>2021-03-24T00:22:50+00:00</updated>
<author>
<name>Dmitry Vyukov</name>
<email>dvyukov@google.com</email>
</author>
<published>2021-03-23T06:49:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=5aa3afe107d9099fc0dea2acf82c3e3c8f0f20e2'/>
<id>5aa3afe107d9099fc0dea2acf82c3e3c8f0f20e2</id>
<content type='text'>
netdev_wait_allrefs() issues a warning if refcount does not drop to 0
after 10 seconds. While 10 second wait generally should not happen
under normal workload in normal environment, it seems to fire falsely
very often during fuzzing and/or in qemu emulation (~10x slower).
At least it's not possible to understand if it's really a false
positive or not. Automated testing generally bumps all timeouts
to very high values to avoid flake failures.
Add net.core.netdev_unregister_timeout_secs sysctl to make
the timeout configurable for automated testing systems.
Lowering the timeout may also be useful for e.g. manual bisection.
The default value matches the current behavior.

Signed-off-by: Dmitry Vyukov &lt;dvyukov@google.com&gt;
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=211877
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
netdev_wait_allrefs() issues a warning if refcount does not drop to 0
after 10 seconds. While 10 second wait generally should not happen
under normal workload in normal environment, it seems to fire falsely
very often during fuzzing and/or in qemu emulation (~10x slower).
At least it's not possible to understand if it's really a false
positive or not. Automated testing generally bumps all timeouts
to very high values to avoid flake failures.
Add net.core.netdev_unregister_timeout_secs sysctl to make
the timeout configurable for automated testing systems.
Lowering the timeout may also be useful for e.g. manual bisection.
The default value matches the current behavior.

Signed-off-by: Dmitry Vyukov &lt;dvyukov@google.com&gt;
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=211877
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/vmscan: restore zone_reclaim_mode ABI</title>
<updated>2021-02-24T21:38:34+00:00</updated>
<author>
<name>Dave Hansen</name>
<email>dave.hansen@linux.intel.com</email>
</author>
<published>2021-02-24T20:09:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=519983645a9f2ec339cabfa0c6ef7b09be985dd0'/>
<id>519983645a9f2ec339cabfa0c6ef7b09be985dd0</id>
<content type='text'>
I went to go add a new RECLAIM_* mode for the zone_reclaim_mode sysctl.
Like a good kernel developer, I also went to go update the
documentation.  I noticed that the bits in the documentation didn't
match the bits in the #defines.

The VM never explicitly checks the RECLAIM_ZONE bit.  The bit is,
however implicitly checked when checking 'node_reclaim_mode==0'.  The
RECLAIM_ZONE #define was removed in a cleanup.  That, by itself is fine.

But, when the bit was removed (bit 0) the _other_ bit locations also got
changed.  That's not OK because the bit values are documented to mean
one specific thing.  Users surely do not expect the meaning to change
from kernel to kernel.

The end result is that if someone had a script that did:

	sysctl vm.zone_reclaim_mode=1

it would have gone from enabling node reclaim for clean unmapped pages
to writing out pages during node reclaim after the commit in question.
That's not great.

Put the bits back the way they were and add a comment so something like
this is a bit harder to do again.  Update the documentation to make it
clear that the first bit is ignored.

Link: https://lkml.kernel.org/r/20210219172555.FF0CDF23@viggo.jf.intel.com
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Fixes: 648b5cf368e0 ("mm/vmscan: remove unused RECLAIM_OFF/RECLAIM_ZONE")
Reviewed-by: Ben Widawsky &lt;ben.widawsky@intel.com&gt;
Reviewed-by: Oscar Salvador &lt;osalvador@suse.de&gt;
Acked-by: David Rientjes &lt;rientjes@google.com&gt;
Acked-by: Christoph Lameter &lt;cl@linux.com&gt;
Cc: Alex Shi &lt;alex.shi@linux.alibaba.com&gt;
Cc: Daniel Wagner &lt;dwagner@suse.de&gt;
Cc: "Tobin C. Harding" &lt;tobin@kernel.org&gt;
Cc: Christoph Lameter &lt;cl@linux.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Huang Ying &lt;ying.huang@intel.com&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: Qian Cai &lt;cai@lca.pw&gt;
Cc: &lt;stable@vger.kernel.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>
I went to go add a new RECLAIM_* mode for the zone_reclaim_mode sysctl.
Like a good kernel developer, I also went to go update the
documentation.  I noticed that the bits in the documentation didn't
match the bits in the #defines.

The VM never explicitly checks the RECLAIM_ZONE bit.  The bit is,
however implicitly checked when checking 'node_reclaim_mode==0'.  The
RECLAIM_ZONE #define was removed in a cleanup.  That, by itself is fine.

But, when the bit was removed (bit 0) the _other_ bit locations also got
changed.  That's not OK because the bit values are documented to mean
one specific thing.  Users surely do not expect the meaning to change
from kernel to kernel.

The end result is that if someone had a script that did:

	sysctl vm.zone_reclaim_mode=1

it would have gone from enabling node reclaim for clean unmapped pages
to writing out pages during node reclaim after the commit in question.
That's not great.

Put the bits back the way they were and add a comment so something like
this is a bit harder to do again.  Update the documentation to make it
clear that the first bit is ignored.

Link: https://lkml.kernel.org/r/20210219172555.FF0CDF23@viggo.jf.intel.com
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Fixes: 648b5cf368e0 ("mm/vmscan: remove unused RECLAIM_OFF/RECLAIM_ZONE")
Reviewed-by: Ben Widawsky &lt;ben.widawsky@intel.com&gt;
Reviewed-by: Oscar Salvador &lt;osalvador@suse.de&gt;
Acked-by: David Rientjes &lt;rientjes@google.com&gt;
Acked-by: Christoph Lameter &lt;cl@linux.com&gt;
Cc: Alex Shi &lt;alex.shi@linux.alibaba.com&gt;
Cc: Daniel Wagner &lt;dwagner@suse.de&gt;
Cc: "Tobin C. Harding" &lt;tobin@kernel.org&gt;
Cc: Christoph Lameter &lt;cl@linux.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Huang Ying &lt;ying.huang@intel.com&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: Qian Cai &lt;cai@lca.pw&gt;
Cc: &lt;stable@vger.kernel.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>
<entry>
<title>Update Documentation/admin-guide/sysctl/fs.rst</title>
<updated>2021-01-28T22:45:10+00:00</updated>
<author>
<name>Eric Curtin</name>
<email>ericcurtin17@gmail.com</email>
</author>
<published>2021-01-20T13:26:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c66cb171bc308c64083f3bb173152db68e06e79f'/>
<id>c66cb171bc308c64083f3bb173152db68e06e79f</id>
<content type='text'>
max_user_watches for epoll should say 1/25, rather than 1/32

Signed-off-by: Eric Curtin &lt;ericcurtin17@gmail.com&gt;
Link: https://lore.kernel.org/r/20210120132648.19046-1-ericcurtin17@gmail.com
Signed-off-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
max_user_watches for epoll should say 1/25, rather than 1/32

Signed-off-by: Eric Curtin &lt;ericcurtin17@gmail.com&gt;
Link: https://lore.kernel.org/r/20210120132648.19046-1-ericcurtin17@gmail.com
Signed-off-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'docs-5.11-2' of git://git.lwn.net/linux</title>
<updated>2020-12-24T22:20:33+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-12-24T22:20:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=71c5f03154ac1cb27423b984743ccc2f5d11d14d'/>
<id>71c5f03154ac1cb27423b984743ccc2f5d11d14d</id>
<content type='text'>
Pull documentation fixes from Jonathan Corbet:
 "A small set of late-arriving, small documentation fixes"

* tag 'docs-5.11-2' of git://git.lwn.net/linux:
  docs: admin-guide: Fix default value of max_map_count in sysctl/vm.rst
  Documentation/submitting-patches: Document the SoB chain
  Documentation: process: Correct numbering
  docs: submitting-patches: Trivial - fix grammatical error
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull documentation fixes from Jonathan Corbet:
 "A small set of late-arriving, small documentation fixes"

* tag 'docs-5.11-2' of git://git.lwn.net/linux:
  docs: admin-guide: Fix default value of max_map_count in sysctl/vm.rst
  Documentation/submitting-patches: Document the SoB chain
  Documentation: process: Correct numbering
  docs: submitting-patches: Trivial - fix grammatical error
</pre>
</div>
</content>
</entry>
<entry>
<title>docs: admin-guide: Fix default value of max_map_count in sysctl/vm.rst</title>
<updated>2020-12-21T16:59:07+00:00</updated>
<author>
<name>Fengfei Xi</name>
<email>xi.fengfei@h3c.com</email>
</author>
<published>2020-12-10T08:21:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c635b0cea6b812898563809a13e65278989b2c72'/>
<id>c635b0cea6b812898563809a13e65278989b2c72</id>
<content type='text'>
Since the default value of sysctl_max_map_count is defined as
DEFAULT_MAX_MAP_COUNT from mm/util.c

    int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;

DEFAULT_MAX_MAP_COUNT is defined as 65530 (65535-5) in include/linux/mm.h

    #define MAPCOUNT_ELF_CORE_MARGIN        (5)
    #define DEFAULT_MAX_MAP_COUNT   (USHRT_MAX - MAPCOUNT_ELF_CORE_MARGIN)

Signed-off-by: Fengfei Xi &lt;xi.fengfei@h3c.com&gt;
Link: https://lore.kernel.org/r/20201210082134.36957-1-xi.fengfei@h3c.com
Signed-off-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Since the default value of sysctl_max_map_count is defined as
DEFAULT_MAX_MAP_COUNT from mm/util.c

    int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;

DEFAULT_MAX_MAP_COUNT is defined as 65530 (65535-5) in include/linux/mm.h

    #define MAPCOUNT_ELF_CORE_MARGIN        (5)
    #define DEFAULT_MAX_MAP_COUNT   (USHRT_MAX - MAPCOUNT_ELF_CORE_MARGIN)

Signed-off-by: Fengfei Xi &lt;xi.fengfei@h3c.com&gt;
Link: https://lore.kernel.org/r/20201210082134.36957-1-xi.fengfei@h3c.com
Signed-off-by: Jonathan Corbet &lt;corbet@lwn.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'akpm' (patches from Andrew)</title>
<updated>2020-12-15T20:53:37+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-12-15T20:53:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ac73e3dc8acd0a3be292755db30388c3580f5674'/>
<id>ac73e3dc8acd0a3be292755db30388c3580f5674</id>
<content type='text'>
Merge misc updates from Andrew Morton:

 - a few random little subsystems

 - almost all of the MM patches which are staged ahead of linux-next
   material. I'll trickle to post-linux-next work in as the dependents
   get merged up.

Subsystems affected by this patch series: kthread, kbuild, ide, ntfs,
ocfs2, arch, and mm (slab-generic, slab, slub, dax, debug, pagecache,
gup, swap, shmem, memcg, pagemap, mremap, hmm, vmalloc, documentation,
kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction,
oom-kill, migration, cma, page-poison, userfaultfd, zswap, zsmalloc,
uaccess, zram, and cleanups).

* emailed patches from Andrew Morton &lt;akpm@linux-foundation.org&gt;: (200 commits)
  mm: cleanup kstrto*() usage
  mm: fix fall-through warnings for Clang
  mm: slub: convert sysfs sprintf family to sysfs_emit/sysfs_emit_at
  mm: shmem: convert shmem_enabled_show to use sysfs_emit_at
  mm:backing-dev: use sysfs_emit in macro defining functions
  mm: huge_memory: convert remaining use of sprintf to sysfs_emit and neatening
  mm: use sysfs_emit for struct kobject * uses
  mm: fix kernel-doc markups
  zram: break the strict dependency from lzo
  zram: add stat to gather incompressible pages since zram set up
  zram: support page writeback
  mm/process_vm_access: remove redundant initialization of iov_r
  mm/zsmalloc.c: rework the list_add code in insert_zspage()
  mm/zswap: move to use crypto_acomp API for hardware acceleration
  mm/zswap: fix passing zero to 'PTR_ERR' warning
  mm/zswap: make struct kernel_param_ops definitions const
  userfaultfd/selftests: hint the test runner on required privilege
  userfaultfd/selftests: fix retval check for userfaultfd_open()
  userfaultfd/selftests: always dump something in modes
  userfaultfd: selftests: make __{s,u}64 format specifiers portable
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Merge misc updates from Andrew Morton:

 - a few random little subsystems

 - almost all of the MM patches which are staged ahead of linux-next
   material. I'll trickle to post-linux-next work in as the dependents
   get merged up.

Subsystems affected by this patch series: kthread, kbuild, ide, ntfs,
ocfs2, arch, and mm (slab-generic, slab, slub, dax, debug, pagecache,
gup, swap, shmem, memcg, pagemap, mremap, hmm, vmalloc, documentation,
kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction,
oom-kill, migration, cma, page-poison, userfaultfd, zswap, zsmalloc,
uaccess, zram, and cleanups).

* emailed patches from Andrew Morton &lt;akpm@linux-foundation.org&gt;: (200 commits)
  mm: cleanup kstrto*() usage
  mm: fix fall-through warnings for Clang
  mm: slub: convert sysfs sprintf family to sysfs_emit/sysfs_emit_at
  mm: shmem: convert shmem_enabled_show to use sysfs_emit_at
  mm:backing-dev: use sysfs_emit in macro defining functions
  mm: huge_memory: convert remaining use of sprintf to sysfs_emit and neatening
  mm: use sysfs_emit for struct kobject * uses
  mm: fix kernel-doc markups
  zram: break the strict dependency from lzo
  zram: add stat to gather incompressible pages since zram set up
  zram: support page writeback
  mm/process_vm_access: remove redundant initialization of iov_r
  mm/zsmalloc.c: rework the list_add code in insert_zspage()
  mm/zswap: move to use crypto_acomp API for hardware acceleration
  mm/zswap: fix passing zero to 'PTR_ERR' warning
  mm/zswap: make struct kernel_param_ops definitions const
  userfaultfd/selftests: hint the test runner on required privilege
  userfaultfd/selftests: fix retval check for userfaultfd_open()
  userfaultfd/selftests: always dump something in modes
  userfaultfd: selftests: make __{s,u}64 format specifiers portable
  ...
</pre>
</div>
</content>
</entry>
</feed>
