* [PATCH man-pages 0/5] {ioctl_}userfaultfd.2: yet another update
@ 2017-05-01 5:43 ` Mike Rapoport
0 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-01 5:43 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man, Mike Rapoport
Hi Michael,
These updates pretty much complete the coverage of 4.11 additions, IMHO.
Mike Rapoport (5):
ioctl_userfaultfd.2: update description of shared memory areas
ioctl_userfaultfd.2: UFFDIO_COPY: add ENOENT and ENOSPC description
ioctl_userfaultfd.2: add BUGS section
userfaultfd.2: add note about asynchronios events delivery
userfaultfd.2: update VERSIONS section with 4.11 chanegs
man2/ioctl_userfaultfd.2 | 35 +++++++++++++++++++++++++++++++++--
man2/userfaultfd.2 | 15 +++++++++++++++
2 files changed, 48 insertions(+), 2 deletions(-)
--
1.9.1
^ permalink raw reply [flat|nested] 41+ messages in thread
* [PATCH man-pages 0/5] {ioctl_}userfaultfd.2: yet another update
@ 2017-05-01 5:43 ` Mike Rapoport
0 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-01 5:43 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man, Mike Rapoport
Hi Michael,
These updates pretty much complete the coverage of 4.11 additions, IMHO.
Mike Rapoport (5):
ioctl_userfaultfd.2: update description of shared memory areas
ioctl_userfaultfd.2: UFFDIO_COPY: add ENOENT and ENOSPC description
ioctl_userfaultfd.2: add BUGS section
userfaultfd.2: add note about asynchronios events delivery
userfaultfd.2: update VERSIONS section with 4.11 chanegs
man2/ioctl_userfaultfd.2 | 35 +++++++++++++++++++++++++++++++++--
man2/userfaultfd.2 | 15 +++++++++++++++
2 files changed, 48 insertions(+), 2 deletions(-)
--
1.9.1
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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^ permalink raw reply [flat|nested] 41+ messages in thread
* [PATCH man-pages 1/5] ioctl_userfaultfd.2: update description of shared memory areas
2017-05-01 5:43 ` Mike Rapoport
@ 2017-05-01 5:43 ` Mike Rapoport
-1 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-01 5:43 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man, Mike Rapoport
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
---
man2/ioctl_userfaultfd.2 | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
index 889feb9..6edd396 100644
--- a/man2/ioctl_userfaultfd.2
+++ b/man2/ioctl_userfaultfd.2
@@ -181,8 +181,17 @@ virtual memory areas
.TP
.B UFFD_FEATURE_MISSING_SHMEM
If this feature bit is set,
-the kernel supports registering userfaultfd ranges on tmpfs
-virtual memory areas
+the kernel supports registering userfaultfd ranges on shared memory areas.
+This includes all kernel shared memory APIs:
+System V shared memory,
+tmpfs,
+/dev/zero,
+.BR mmap(2)
+with
+.I MAP_SHARED
+flag set,
+.BR memfd_create (2),
+etc.
The returned
.I ioctls
--
1.9.1
^ permalink raw reply related [flat|nested] 41+ messages in thread
* [PATCH man-pages 1/5] ioctl_userfaultfd.2: update description of shared memory areas
@ 2017-05-01 5:43 ` Mike Rapoport
0 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-01 5:43 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man, Mike Rapoport
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
---
man2/ioctl_userfaultfd.2 | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
index 889feb9..6edd396 100644
--- a/man2/ioctl_userfaultfd.2
+++ b/man2/ioctl_userfaultfd.2
@@ -181,8 +181,17 @@ virtual memory areas
.TP
.B UFFD_FEATURE_MISSING_SHMEM
If this feature bit is set,
-the kernel supports registering userfaultfd ranges on tmpfs
-virtual memory areas
+the kernel supports registering userfaultfd ranges on shared memory areas.
+This includes all kernel shared memory APIs:
+System V shared memory,
+tmpfs,
+/dev/zero,
+.BR mmap(2)
+with
+.I MAP_SHARED
+flag set,
+.BR memfd_create (2),
+etc.
The returned
.I ioctls
--
1.9.1
--
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the body to majordomo@kvack.org. For more info on Linux MM,
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^ permalink raw reply related [flat|nested] 41+ messages in thread
* [PATCH man-pages 2/5] ioctl_userfaultfd.2: UFFDIO_COPY: add ENOENT and ENOSPC description
2017-05-01 5:43 ` Mike Rapoport
@ 2017-05-01 5:43 ` Mike Rapoport
-1 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-01 5:43 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man, Mike Rapoport
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
---
man2/ioctl_userfaultfd.2 | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
index 6edd396..e12b9de 100644
--- a/man2/ioctl_userfaultfd.2
+++ b/man2/ioctl_userfaultfd.2
@@ -481,6 +481,19 @@ was invalid.
An invalid bit was specified in the
.IR mode
field.
+.TP
+.B ENOENT
+(Since Linux 4.11)
+The faulting process has changed
+its virtual memory layout simultaneously with outstanding
+.I UFFDIO_COPY
+operation.
+.TP
+.B ENOSPC
+(Since Linux 4.11)
+The faulting process has exited at the time of
+.I UFFDIO_COPY
+operation.
.\"
.SS UFFDIO_ZEROPAGE
(Since Linux 4.3.)
--
1.9.1
^ permalink raw reply related [flat|nested] 41+ messages in thread
* [PATCH man-pages 2/5] ioctl_userfaultfd.2: UFFDIO_COPY: add ENOENT and ENOSPC description
@ 2017-05-01 5:43 ` Mike Rapoport
0 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-01 5:43 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man, Mike Rapoport
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
---
man2/ioctl_userfaultfd.2 | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
index 6edd396..e12b9de 100644
--- a/man2/ioctl_userfaultfd.2
+++ b/man2/ioctl_userfaultfd.2
@@ -481,6 +481,19 @@ was invalid.
An invalid bit was specified in the
.IR mode
field.
+.TP
+.B ENOENT
+(Since Linux 4.11)
+The faulting process has changed
+its virtual memory layout simultaneously with outstanding
+.I UFFDIO_COPY
+operation.
+.TP
+.B ENOSPC
+(Since Linux 4.11)
+The faulting process has exited at the time of
+.I UFFDIO_COPY
+operation.
.\"
.SS UFFDIO_ZEROPAGE
(Since Linux 4.3.)
--
1.9.1
--
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the body to majordomo@kvack.org. For more info on Linux MM,
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^ permalink raw reply related [flat|nested] 41+ messages in thread
* [PATCH man-pages 3/5] ioctl_userfaultfd.2: add BUGS section
2017-05-01 5:43 ` Mike Rapoport
@ 2017-05-01 5:43 ` Mike Rapoport
-1 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-01 5:43 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man, Mike Rapoport
The features handshake is not quite convenient.
Elaborate about it in the BUGS section.
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
---
man2/ioctl_userfaultfd.2 | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
index e12b9de..50316de 100644
--- a/man2/ioctl_userfaultfd.2
+++ b/man2/ioctl_userfaultfd.2
@@ -650,6 +650,15 @@ operations are Linux-specific.
.SH EXAMPLE
See
.BR userfaultfd (2).
+.SH BUGS
+In order to detect available userfault features and
+enable certain subset of those features
+the usefault file descriptor must be closed after the first
+.BR UFFDIO_API
+operation that queries features availability and re-opened before
+the second
+.BR UFFDIO_API
+call that actually enables the desired features.
.SH SEE ALSO
.BR ioctl (2),
.BR mmap (2),
--
1.9.1
^ permalink raw reply related [flat|nested] 41+ messages in thread
* [PATCH man-pages 3/5] ioctl_userfaultfd.2: add BUGS section
@ 2017-05-01 5:43 ` Mike Rapoport
0 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-01 5:43 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man, Mike Rapoport
The features handshake is not quite convenient.
Elaborate about it in the BUGS section.
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
---
man2/ioctl_userfaultfd.2 | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
index e12b9de..50316de 100644
--- a/man2/ioctl_userfaultfd.2
+++ b/man2/ioctl_userfaultfd.2
@@ -650,6 +650,15 @@ operations are Linux-specific.
.SH EXAMPLE
See
.BR userfaultfd (2).
+.SH BUGS
+In order to detect available userfault features and
+enable certain subset of those features
+the usefault file descriptor must be closed after the first
+.BR UFFDIO_API
+operation that queries features availability and re-opened before
+the second
+.BR UFFDIO_API
+call that actually enables the desired features.
.SH SEE ALSO
.BR ioctl (2),
.BR mmap (2),
--
1.9.1
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
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^ permalink raw reply related [flat|nested] 41+ messages in thread
* [PATCH man-pages 4/5] userfaultfd.2: add note about asynchronios events delivery
2017-05-01 5:43 ` Mike Rapoport
@ 2017-05-01 5:43 ` Mike Rapoport
-1 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-01 5:43 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man, Mike Rapoport
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
---
man2/userfaultfd.2 | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2
index 8b89162..f177bba 100644
--- a/man2/userfaultfd.2
+++ b/man2/userfaultfd.2
@@ -112,6 +112,18 @@ created for the child process,
which allows userfaultfd monitor to perform user-space paging
for the child process.
+Unlike page faults which have to be synchronous and require
+explicit or implicit wakeup,
+all other events are delivered asynchronously and
+the non-cooperative process resumes execution as
+soon as manager executes
+.BR read(2).
+The userfaultfd manager should carefully synchronize calls
+to UFFDIO_COPY with the events processing.
+
+The current asynchronous model of the event delivery is optimal for
+single threaded non-cooperative userfaultfd manager implementations.
+
.\" FIXME elaborate about non-cooperating mode, describe its limitations
.\" for kernels before 4.11, features added in 4.11
.\" and limitations remaining in 4.11
--
1.9.1
^ permalink raw reply related [flat|nested] 41+ messages in thread
* [PATCH man-pages 4/5] userfaultfd.2: add note about asynchronios events delivery
@ 2017-05-01 5:43 ` Mike Rapoport
0 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-01 5:43 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man, Mike Rapoport
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
---
man2/userfaultfd.2 | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2
index 8b89162..f177bba 100644
--- a/man2/userfaultfd.2
+++ b/man2/userfaultfd.2
@@ -112,6 +112,18 @@ created for the child process,
which allows userfaultfd monitor to perform user-space paging
for the child process.
+Unlike page faults which have to be synchronous and require
+explicit or implicit wakeup,
+all other events are delivered asynchronously and
+the non-cooperative process resumes execution as
+soon as manager executes
+.BR read(2).
+The userfaultfd manager should carefully synchronize calls
+to UFFDIO_COPY with the events processing.
+
+The current asynchronous model of the event delivery is optimal for
+single threaded non-cooperative userfaultfd manager implementations.
+
.\" FIXME elaborate about non-cooperating mode, describe its limitations
.\" for kernels before 4.11, features added in 4.11
.\" and limitations remaining in 4.11
--
1.9.1
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
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^ permalink raw reply related [flat|nested] 41+ messages in thread
* [PATCH man-pages 5/5] userfaultfd.2: update VERSIONS section with 4.11 chanegs
2017-05-01 5:43 ` Mike Rapoport
@ 2017-05-01 5:43 ` Mike Rapoport
-1 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-01 5:43 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man, Mike Rapoport
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
---
man2/userfaultfd.2 | 3 +++
1 file changed, 3 insertions(+)
diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2
index f177bba..07a69f1 100644
--- a/man2/userfaultfd.2
+++ b/man2/userfaultfd.2
@@ -404,6 +404,9 @@ Insufficient kernel memory was available.
The
.BR userfaultfd ()
system call first appeared in Linux 4.3.
+
+The support for hugetlbfs and shared memory areas and
+non-page-fault events was added in Linux 4.11
.SH CONFORMING TO
.BR userfaultfd ()
is Linux-specific and should not be used in programs intended to be
--
1.9.1
^ permalink raw reply related [flat|nested] 41+ messages in thread
* [PATCH man-pages 5/5] userfaultfd.2: update VERSIONS section with 4.11 chanegs
@ 2017-05-01 5:43 ` Mike Rapoport
0 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-01 5:43 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man, Mike Rapoport
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
---
man2/userfaultfd.2 | 3 +++
1 file changed, 3 insertions(+)
diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2
index f177bba..07a69f1 100644
--- a/man2/userfaultfd.2
+++ b/man2/userfaultfd.2
@@ -404,6 +404,9 @@ Insufficient kernel memory was available.
The
.BR userfaultfd ()
system call first appeared in Linux 4.3.
+
+The support for hugetlbfs and shared memory areas and
+non-page-fault events was added in Linux 4.11
.SH CONFORMING TO
.BR userfaultfd ()
is Linux-specific and should not be used in programs intended to be
--
1.9.1
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
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^ permalink raw reply related [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 1/5] ioctl_userfaultfd.2: update description of shared memory areas
2017-05-01 5:43 ` Mike Rapoport
@ 2017-05-01 18:33 ` Michael Kerrisk (man-pages)
-1 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-01 18:33 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
Hello Mike,
I've applied this patch, but have a question.
On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
> ---
> man2/ioctl_userfaultfd.2 | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
> index 889feb9..6edd396 100644
> --- a/man2/ioctl_userfaultfd.2
> +++ b/man2/ioctl_userfaultfd.2
> @@ -181,8 +181,17 @@ virtual memory areas
> .TP
> .B UFFD_FEATURE_MISSING_SHMEM
> If this feature bit is set,
> -the kernel supports registering userfaultfd ranges on tmpfs
> -virtual memory areas
> +the kernel supports registering userfaultfd ranges on shared memory areas.
> +This includes all kernel shared memory APIs:
> +System V shared memory,
> +tmpfs,
> +/dev/zero,
> +.BR mmap(2)
> +with
> +.I MAP_SHARED
> +flag set,
> +.BR memfd_create (2),
> +etc.
>
> The returned
> .I ioctls
Does the change in this patch represent a change that occurred in
Linux 4.11? If so, I think this needs to be said explicitly in the text.
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 1/5] ioctl_userfaultfd.2: update description of shared memory areas
@ 2017-05-01 18:33 ` Michael Kerrisk (man-pages)
0 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-01 18:33 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
Hello Mike,
I've applied this patch, but have a question.
On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
> ---
> man2/ioctl_userfaultfd.2 | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
> index 889feb9..6edd396 100644
> --- a/man2/ioctl_userfaultfd.2
> +++ b/man2/ioctl_userfaultfd.2
> @@ -181,8 +181,17 @@ virtual memory areas
> .TP
> .B UFFD_FEATURE_MISSING_SHMEM
> If this feature bit is set,
> -the kernel supports registering userfaultfd ranges on tmpfs
> -virtual memory areas
> +the kernel supports registering userfaultfd ranges on shared memory areas.
> +This includes all kernel shared memory APIs:
> +System V shared memory,
> +tmpfs,
> +/dev/zero,
> +.BR mmap(2)
> +with
> +.I MAP_SHARED
> +flag set,
> +.BR memfd_create (2),
> +etc.
>
> The returned
> .I ioctls
Does the change in this patch represent a change that occurred in
Linux 4.11? If so, I think this needs to be said explicitly in the text.
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 2/5] ioctl_userfaultfd.2: UFFDIO_COPY: add ENOENT and ENOSPC description
2017-05-01 5:43 ` Mike Rapoport
@ 2017-05-01 18:33 ` Michael Kerrisk (man-pages)
-1 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-01 18:33 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Thanks, Mike. Applied.
Cheers,
Michael
> ---
> man2/ioctl_userfaultfd.2 | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
> index 6edd396..e12b9de 100644
> --- a/man2/ioctl_userfaultfd.2
> +++ b/man2/ioctl_userfaultfd.2
> @@ -481,6 +481,19 @@ was invalid.
> An invalid bit was specified in the
> .IR mode
> field.
> +.TP
> +.B ENOENT
> +(Since Linux 4.11)
> +The faulting process has changed
> +its virtual memory layout simultaneously with outstanding
> +.I UFFDIO_COPY
> +operation.
> +.TP
> +.B ENOSPC
> +(Since Linux 4.11)
> +The faulting process has exited at the time of
> +.I UFFDIO_COPY
> +operation.
> .\"
> .SS UFFDIO_ZEROPAGE
> (Since Linux 4.3.)
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 2/5] ioctl_userfaultfd.2: UFFDIO_COPY: add ENOENT and ENOSPC description
@ 2017-05-01 18:33 ` Michael Kerrisk (man-pages)
0 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-01 18:33 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Thanks, Mike. Applied.
Cheers,
Michael
> ---
> man2/ioctl_userfaultfd.2 | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
> index 6edd396..e12b9de 100644
> --- a/man2/ioctl_userfaultfd.2
> +++ b/man2/ioctl_userfaultfd.2
> @@ -481,6 +481,19 @@ was invalid.
> An invalid bit was specified in the
> .IR mode
> field.
> +.TP
> +.B ENOENT
> +(Since Linux 4.11)
> +The faulting process has changed
> +its virtual memory layout simultaneously with outstanding
> +.I UFFDIO_COPY
> +operation.
> +.TP
> +.B ENOSPC
> +(Since Linux 4.11)
> +The faulting process has exited at the time of
> +.I UFFDIO_COPY
> +operation.
> .\"
> .SS UFFDIO_ZEROPAGE
> (Since Linux 4.3.)
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
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^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 4/5] userfaultfd.2: add note about asynchronios events delivery
2017-05-01 5:43 ` Mike Rapoport
@ 2017-05-01 18:33 ` Michael Kerrisk (man-pages)
-1 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-01 18:33 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
Hi Mike,
On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Thanks. Applied. One question below.
> ---
> man2/userfaultfd.2 | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2
> index 8b89162..f177bba 100644
> --- a/man2/userfaultfd.2
> +++ b/man2/userfaultfd.2
> @@ -112,6 +112,18 @@ created for the child process,
> which allows userfaultfd monitor to perform user-space paging
> for the child process.
>
> +Unlike page faults which have to be synchronous and require
> +explicit or implicit wakeup,
> +all other events are delivered asynchronously and
> +the non-cooperative process resumes execution as
> +soon as manager executes
> +.BR read(2).
> +The userfaultfd manager should carefully synchronize calls
> +to UFFDIO_COPY with the events processing.
> +
> +The current asynchronous model of the event delivery is optimal for
> +single threaded non-cooperative userfaultfd manager implementations.
The preceding paragraph feels incomplete. It seems like you want to make
a point with that last sentence, but the point is not explicit. What's
missing?
> +
> .\" FIXME elaborate about non-cooperating mode, describe its limitations
> .\" for kernels before 4.11, features added in 4.11
> .\" and limitations remaining in 4.11
>
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 4/5] userfaultfd.2: add note about asynchronios events delivery
@ 2017-05-01 18:33 ` Michael Kerrisk (man-pages)
0 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-01 18:33 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
Hi Mike,
On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Thanks. Applied. One question below.
> ---
> man2/userfaultfd.2 | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2
> index 8b89162..f177bba 100644
> --- a/man2/userfaultfd.2
> +++ b/man2/userfaultfd.2
> @@ -112,6 +112,18 @@ created for the child process,
> which allows userfaultfd monitor to perform user-space paging
> for the child process.
>
> +Unlike page faults which have to be synchronous and require
> +explicit or implicit wakeup,
> +all other events are delivered asynchronously and
> +the non-cooperative process resumes execution as
> +soon as manager executes
> +.BR read(2).
> +The userfaultfd manager should carefully synchronize calls
> +to UFFDIO_COPY with the events processing.
> +
> +The current asynchronous model of the event delivery is optimal for
> +single threaded non-cooperative userfaultfd manager implementations.
The preceding paragraph feels incomplete. It seems like you want to make
a point with that last sentence, but the point is not explicit. What's
missing?
> +
> .\" FIXME elaborate about non-cooperating mode, describe its limitations
> .\" for kernels before 4.11, features added in 4.11
> .\" and limitations remaining in 4.11
>
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 3/5] ioctl_userfaultfd.2: add BUGS section
2017-05-01 5:43 ` Mike Rapoport
@ 2017-05-01 18:33 ` Michael Kerrisk (man-pages)
-1 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-01 18:33 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
Hi Mike,
I've applied this, but have a question.
On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> The features handshake is not quite convenient.
> Elaborate about it in the BUGS section.
>
> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
> ---
> man2/ioctl_userfaultfd.2 | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
> index e12b9de..50316de 100644
> --- a/man2/ioctl_userfaultfd.2
> +++ b/man2/ioctl_userfaultfd.2
> @@ -650,6 +650,15 @@ operations are Linux-specific.
> .SH EXAMPLE
> See
> .BR userfaultfd (2).
> +.SH BUGS
> +In order to detect available userfault features and
> +enable certain subset of those features
I changed "certain" to "some". ("certain subset" here also
would sound like "some particular subset" of those features.)
Okay?
> +the usefault file descriptor must be closed after the first
> +.BR UFFDIO_API
> +operation that queries features availability and re-opened before
> +the second
> +.BR UFFDIO_API
> +call that actually enables the desired features.
> .SH SEE ALSO
> .BR ioctl (2),
> .BR mmap (2),
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 3/5] ioctl_userfaultfd.2: add BUGS section
@ 2017-05-01 18:33 ` Michael Kerrisk (man-pages)
0 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-01 18:33 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
Hi Mike,
I've applied this, but have a question.
On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> The features handshake is not quite convenient.
> Elaborate about it in the BUGS section.
>
> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
> ---
> man2/ioctl_userfaultfd.2 | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
> index e12b9de..50316de 100644
> --- a/man2/ioctl_userfaultfd.2
> +++ b/man2/ioctl_userfaultfd.2
> @@ -650,6 +650,15 @@ operations are Linux-specific.
> .SH EXAMPLE
> See
> .BR userfaultfd (2).
> +.SH BUGS
> +In order to detect available userfault features and
> +enable certain subset of those features
I changed "certain" to "some". ("certain subset" here also
would sound like "some particular subset" of those features.)
Okay?
> +the usefault file descriptor must be closed after the first
> +.BR UFFDIO_API
> +operation that queries features availability and re-opened before
> +the second
> +.BR UFFDIO_API
> +call that actually enables the desired features.
> .SH SEE ALSO
> .BR ioctl (2),
> .BR mmap (2),
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
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^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 5/5] userfaultfd.2: update VERSIONS section with 4.11 chanegs
2017-05-01 5:43 ` Mike Rapoport
@ 2017-05-01 18:33 ` Michael Kerrisk (man-pages)
-1 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-01 18:33 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
Hi Mike,
On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Thanks. Applied.
Cheers,
Michael
> ---
> man2/userfaultfd.2 | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2
> index f177bba..07a69f1 100644
> --- a/man2/userfaultfd.2
> +++ b/man2/userfaultfd.2
> @@ -404,6 +404,9 @@ Insufficient kernel memory was available.
> The
> .BR userfaultfd ()
> system call first appeared in Linux 4.3.
> +
> +The support for hugetlbfs and shared memory areas and
> +non-page-fault events was added in Linux 4.11
> .SH CONFORMING TO
> .BR userfaultfd ()
> is Linux-specific and should not be used in programs intended to be
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 5/5] userfaultfd.2: update VERSIONS section with 4.11 chanegs
@ 2017-05-01 18:33 ` Michael Kerrisk (man-pages)
0 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-01 18:33 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
Hi Mike,
On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Thanks. Applied.
Cheers,
Michael
> ---
> man2/userfaultfd.2 | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2
> index f177bba..07a69f1 100644
> --- a/man2/userfaultfd.2
> +++ b/man2/userfaultfd.2
> @@ -404,6 +404,9 @@ Insufficient kernel memory was available.
> The
> .BR userfaultfd ()
> system call first appeared in Linux 4.3.
> +
> +The support for hugetlbfs and shared memory areas and
> +non-page-fault events was added in Linux 4.11
> .SH CONFORMING TO
> .BR userfaultfd ()
> is Linux-specific and should not be used in programs intended to be
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
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^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 0/5] {ioctl_}userfaultfd.2: yet another update
2017-05-01 5:43 ` Mike Rapoport
@ 2017-05-01 18:34 ` Michael Kerrisk (man-pages)
-1 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-01 18:34 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
Hi Mike,
On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> Hi Michael,
>
> These updates pretty much complete the coverage of 4.11 additions, IMHO.
Thanks for this, but we still await input from Andrea
on various points.
> Mike Rapoport (5):
> ioctl_userfaultfd.2: update description of shared memory areas
> ioctl_userfaultfd.2: UFFDIO_COPY: add ENOENT and ENOSPC description
> ioctl_userfaultfd.2: add BUGS section
> userfaultfd.2: add note about asynchronios events delivery
> userfaultfd.2: update VERSIONS section with 4.11 chanegs
>
> man2/ioctl_userfaultfd.2 | 35 +++++++++++++++++++++++++++++++++--
> man2/userfaultfd.2 | 15 +++++++++++++++
> 2 files changed, 48 insertions(+), 2 deletions(-)
I've applied all of the above, and done some light editing.
Could you please check my changes in the following commits:
5191c68806c8ac73fdc89586cde434d2766abb5c
265225c1e2311ae26ead116e6c8d2cedd46144fa
Thanks,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 0/5] {ioctl_}userfaultfd.2: yet another update
@ 2017-05-01 18:34 ` Michael Kerrisk (man-pages)
0 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-01 18:34 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
Hi Mike,
On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> Hi Michael,
>
> These updates pretty much complete the coverage of 4.11 additions, IMHO.
Thanks for this, but we still await input from Andrea
on various points.
> Mike Rapoport (5):
> ioctl_userfaultfd.2: update description of shared memory areas
> ioctl_userfaultfd.2: UFFDIO_COPY: add ENOENT and ENOSPC description
> ioctl_userfaultfd.2: add BUGS section
> userfaultfd.2: add note about asynchronios events delivery
> userfaultfd.2: update VERSIONS section with 4.11 chanegs
>
> man2/ioctl_userfaultfd.2 | 35 +++++++++++++++++++++++++++++++++--
> man2/userfaultfd.2 | 15 +++++++++++++++
> 2 files changed, 48 insertions(+), 2 deletions(-)
I've applied all of the above, and done some light editing.
Could you please check my changes in the following commits:
5191c68806c8ac73fdc89586cde434d2766abb5c
265225c1e2311ae26ead116e6c8d2cedd46144fa
Thanks,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 1/5] ioctl_userfaultfd.2: update description of shared memory areas
@ 2017-05-02 9:31 ` Mike Rapoport
0 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-02 9:31 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On Mon, May 01, 2017 at 08:33:31PM +0200, Michael Kerrisk (man-pages) wrote:
> Hello Mike,
>
> I've applied this patch, but have a question.
>
> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> > Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
> > ---
> > man2/ioctl_userfaultfd.2 | 13 +++++++++++--
> > 1 file changed, 11 insertions(+), 2 deletions(-)
> >
> > diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
> > index 889feb9..6edd396 100644
> > --- a/man2/ioctl_userfaultfd.2
> > +++ b/man2/ioctl_userfaultfd.2
> > @@ -181,8 +181,17 @@ virtual memory areas
> > .TP
> > .B UFFD_FEATURE_MISSING_SHMEM
> > If this feature bit is set,
> > -the kernel supports registering userfaultfd ranges on tmpfs
> > -virtual memory areas
> > +the kernel supports registering userfaultfd ranges on shared memory areas.
> > +This includes all kernel shared memory APIs:
> > +System V shared memory,
> > +tmpfs,
> > +/dev/zero,
> > +.BR mmap(2)
> > +with
> > +.I MAP_SHARED
> > +flag set,
> > +.BR memfd_create (2),
> > +etc.
> >
> > The returned
> > .I ioctls
>
> Does the change in this patch represent a change that occurred in
> Linux 4.11? If so, I think this needs to be said explicitly in the text.
The patch only extends the description of UFFD_FEATURE_MISSING_SHMEM. The
feature is indeed available from 4.11, but that is said a few lives above
(line 136 in ioctl_userfaultfd.2)
> Cheers,
>
> Michael
>
>
>
> --
> Michael Kerrisk
> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
> Linux/UNIX System Programming Training: http://man7.org/training/
>
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 1/5] ioctl_userfaultfd.2: update description of shared memory areas
@ 2017-05-02 9:31 ` Mike Rapoport
0 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-02 9:31 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel-u79uwXL29TY76Z2rM5mHXA,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg,
linux-man-u79uwXL29TY76Z2rM5mHXA
On Mon, May 01, 2017 at 08:33:31PM +0200, Michael Kerrisk (man-pages) wrote:
> Hello Mike,
>
> I've applied this patch, but have a question.
>
> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> > Signed-off-by: Mike Rapoport <rppt-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> > ---
> > man2/ioctl_userfaultfd.2 | 13 +++++++++++--
> > 1 file changed, 11 insertions(+), 2 deletions(-)
> >
> > diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
> > index 889feb9..6edd396 100644
> > --- a/man2/ioctl_userfaultfd.2
> > +++ b/man2/ioctl_userfaultfd.2
> > @@ -181,8 +181,17 @@ virtual memory areas
> > .TP
> > .B UFFD_FEATURE_MISSING_SHMEM
> > If this feature bit is set,
> > -the kernel supports registering userfaultfd ranges on tmpfs
> > -virtual memory areas
> > +the kernel supports registering userfaultfd ranges on shared memory areas.
> > +This includes all kernel shared memory APIs:
> > +System V shared memory,
> > +tmpfs,
> > +/dev/zero,
> > +.BR mmap(2)
> > +with
> > +.I MAP_SHARED
> > +flag set,
> > +.BR memfd_create (2),
> > +etc.
> >
> > The returned
> > .I ioctls
>
> Does the change in this patch represent a change that occurred in
> Linux 4.11? If so, I think this needs to be said explicitly in the text.
The patch only extends the description of UFFD_FEATURE_MISSING_SHMEM. The
feature is indeed available from 4.11, but that is said a few lives above
(line 136 in ioctl_userfaultfd.2)
> Cheers,
>
> Michael
>
>
>
> --
> Michael Kerrisk
> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
> Linux/UNIX System Programming Training: http://man7.org/training/
>
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To unsubscribe from this list: send the line "unsubscribe linux-man" in
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^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 1/5] ioctl_userfaultfd.2: update description of shared memory areas
@ 2017-05-02 9:31 ` Mike Rapoport
0 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-02 9:31 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On Mon, May 01, 2017 at 08:33:31PM +0200, Michael Kerrisk (man-pages) wrote:
> Hello Mike,
>
> I've applied this patch, but have a question.
>
> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> > Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
> > ---
> > man2/ioctl_userfaultfd.2 | 13 +++++++++++--
> > 1 file changed, 11 insertions(+), 2 deletions(-)
> >
> > diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
> > index 889feb9..6edd396 100644
> > --- a/man2/ioctl_userfaultfd.2
> > +++ b/man2/ioctl_userfaultfd.2
> > @@ -181,8 +181,17 @@ virtual memory areas
> > .TP
> > .B UFFD_FEATURE_MISSING_SHMEM
> > If this feature bit is set,
> > -the kernel supports registering userfaultfd ranges on tmpfs
> > -virtual memory areas
> > +the kernel supports registering userfaultfd ranges on shared memory areas.
> > +This includes all kernel shared memory APIs:
> > +System V shared memory,
> > +tmpfs,
> > +/dev/zero,
> > +.BR mmap(2)
> > +with
> > +.I MAP_SHARED
> > +flag set,
> > +.BR memfd_create (2),
> > +etc.
> >
> > The returned
> > .I ioctls
>
> Does the change in this patch represent a change that occurred in
> Linux 4.11? If so, I think this needs to be said explicitly in the text.
The patch only extends the description of UFFD_FEATURE_MISSING_SHMEM. The
feature is indeed available from 4.11, but that is said a few lives above
(line 136 in ioctl_userfaultfd.2)
> Cheers,
>
> Michael
>
>
>
> --
> Michael Kerrisk
> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
> Linux/UNIX System Programming Training: http://man7.org/training/
>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
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Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 3/5] ioctl_userfaultfd.2: add BUGS section
@ 2017-05-02 9:32 ` Mike Rapoport
0 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-02 9:32 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On Mon, May 01, 2017 at 08:33:50PM +0200, Michael Kerrisk (man-pages) wrote:
> Hi Mike,
>
> I've applied this, but have a question.
>
> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> > The features handshake is not quite convenient.
> > Elaborate about it in the BUGS section.
> >
> > Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
> > ---
> > man2/ioctl_userfaultfd.2 | 9 +++++++++
> > 1 file changed, 9 insertions(+)
> >
> > diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
> > index e12b9de..50316de 100644
> > --- a/man2/ioctl_userfaultfd.2
> > +++ b/man2/ioctl_userfaultfd.2
> > @@ -650,6 +650,15 @@ operations are Linux-specific.
> > .SH EXAMPLE
> > See
> > .BR userfaultfd (2).
> > +.SH BUGS
> > +In order to detect available userfault features and
> > +enable certain subset of those features
>
> I changed "certain" to "some". ("certain subset" here also
> would sound like "some particular subset" of those features.)
> Okay?
Yes, sure.
> > +the usefault file descriptor must be closed after the first
> > +.BR UFFDIO_API
> > +operation that queries features availability and re-opened before
> > +the second
> > +.BR UFFDIO_API
> > +call that actually enables the desired features.
> > .SH SEE ALSO
> > .BR ioctl (2),
> > .BR mmap (2),
>
> Cheers,
>
> Michael
>
>
>
> --
> Michael Kerrisk
> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
> Linux/UNIX System Programming Training: http://man7.org/training/
>
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 3/5] ioctl_userfaultfd.2: add BUGS section
@ 2017-05-02 9:32 ` Mike Rapoport
0 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-02 9:32 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel-u79uwXL29TY76Z2rM5mHXA,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg,
linux-man-u79uwXL29TY76Z2rM5mHXA
On Mon, May 01, 2017 at 08:33:50PM +0200, Michael Kerrisk (man-pages) wrote:
> Hi Mike,
>
> I've applied this, but have a question.
>
> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> > The features handshake is not quite convenient.
> > Elaborate about it in the BUGS section.
> >
> > Signed-off-by: Mike Rapoport <rppt-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> > ---
> > man2/ioctl_userfaultfd.2 | 9 +++++++++
> > 1 file changed, 9 insertions(+)
> >
> > diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
> > index e12b9de..50316de 100644
> > --- a/man2/ioctl_userfaultfd.2
> > +++ b/man2/ioctl_userfaultfd.2
> > @@ -650,6 +650,15 @@ operations are Linux-specific.
> > .SH EXAMPLE
> > See
> > .BR userfaultfd (2).
> > +.SH BUGS
> > +In order to detect available userfault features and
> > +enable certain subset of those features
>
> I changed "certain" to "some". ("certain subset" here also
> would sound like "some particular subset" of those features.)
> Okay?
Yes, sure.
> > +the usefault file descriptor must be closed after the first
> > +.BR UFFDIO_API
> > +operation that queries features availability and re-opened before
> > +the second
> > +.BR UFFDIO_API
> > +call that actually enables the desired features.
> > .SH SEE ALSO
> > .BR ioctl (2),
> > .BR mmap (2),
>
> Cheers,
>
> Michael
>
>
>
> --
> Michael Kerrisk
> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
> Linux/UNIX System Programming Training: http://man7.org/training/
>
--
To unsubscribe from this list: send the line "unsubscribe linux-man" in
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More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 3/5] ioctl_userfaultfd.2: add BUGS section
@ 2017-05-02 9:32 ` Mike Rapoport
0 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-02 9:32 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On Mon, May 01, 2017 at 08:33:50PM +0200, Michael Kerrisk (man-pages) wrote:
> Hi Mike,
>
> I've applied this, but have a question.
>
> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> > The features handshake is not quite convenient.
> > Elaborate about it in the BUGS section.
> >
> > Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
> > ---
> > man2/ioctl_userfaultfd.2 | 9 +++++++++
> > 1 file changed, 9 insertions(+)
> >
> > diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
> > index e12b9de..50316de 100644
> > --- a/man2/ioctl_userfaultfd.2
> > +++ b/man2/ioctl_userfaultfd.2
> > @@ -650,6 +650,15 @@ operations are Linux-specific.
> > .SH EXAMPLE
> > See
> > .BR userfaultfd (2).
> > +.SH BUGS
> > +In order to detect available userfault features and
> > +enable certain subset of those features
>
> I changed "certain" to "some". ("certain subset" here also
> would sound like "some particular subset" of those features.)
> Okay?
Yes, sure.
> > +the usefault file descriptor must be closed after the first
> > +.BR UFFDIO_API
> > +operation that queries features availability and re-opened before
> > +the second
> > +.BR UFFDIO_API
> > +call that actually enables the desired features.
> > .SH SEE ALSO
> > .BR ioctl (2),
> > .BR mmap (2),
>
> Cheers,
>
> Michael
>
>
>
> --
> Michael Kerrisk
> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
> Linux/UNIX System Programming Training: http://man7.org/training/
>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 4/5] userfaultfd.2: add note about asynchronios events delivery
2017-05-01 18:33 ` Michael Kerrisk (man-pages)
@ 2017-05-02 9:46 ` Mike Rapoport
-1 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-02 9:46 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On Mon, May 01, 2017 at 08:33:45PM +0200, Michael Kerrisk (man-pages) wrote:
> Hi Mike,
>
> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> > Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
>
> Thanks. Applied. One question below.
>
> > ---
> > man2/userfaultfd.2 | 12 ++++++++++++
> > 1 file changed, 12 insertions(+)
> >
> > diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2
> > index 8b89162..f177bba 100644
> > --- a/man2/userfaultfd.2
> > +++ b/man2/userfaultfd.2
> > @@ -112,6 +112,18 @@ created for the child process,
> > which allows userfaultfd monitor to perform user-space paging
> > for the child process.
> >
> > +Unlike page faults which have to be synchronous and require
> > +explicit or implicit wakeup,
> > +all other events are delivered asynchronously and
> > +the non-cooperative process resumes execution as
> > +soon as manager executes
> > +.BR read(2).
> > +The userfaultfd manager should carefully synchronize calls
> > +to UFFDIO_COPY with the events processing.
> > +
> > +The current asynchronous model of the event delivery is optimal for
> > +single threaded non-cooperative userfaultfd manager implementations.
>
> The preceding paragraph feels incomplete. It seems like you want to make
> a point with that last sentence, but the point is not explicit. What's
> missing?
I've copied both from Documentation/vm/userfaulftfd.txt, and there we also
talk about possibility of addition of synchronous events delivery and
that makes the paragraph above to seem crippled :)
The major point here is that current events delivery model could be
problematic for multi-threaded monitor. I even suspect that it would be
impossible to ensure synchronization between page faults and non-page
fault events in multi-threaded monitor.
> > +
> > .\" FIXME elaborate about non-cooperating mode, describe its limitations
> > .\" for kernels before 4.11, features added in 4.11
> > .\" and limitations remaining in 4.11
> >
>
> Cheers,
>
> Michael
>
>
>
> --
> Michael Kerrisk
> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
> Linux/UNIX System Programming Training: http://man7.org/training/
>
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 4/5] userfaultfd.2: add note about asynchronios events delivery
@ 2017-05-02 9:46 ` Mike Rapoport
0 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-02 9:46 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On Mon, May 01, 2017 at 08:33:45PM +0200, Michael Kerrisk (man-pages) wrote:
> Hi Mike,
>
> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> > Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
>
> Thanks. Applied. One question below.
>
> > ---
> > man2/userfaultfd.2 | 12 ++++++++++++
> > 1 file changed, 12 insertions(+)
> >
> > diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2
> > index 8b89162..f177bba 100644
> > --- a/man2/userfaultfd.2
> > +++ b/man2/userfaultfd.2
> > @@ -112,6 +112,18 @@ created for the child process,
> > which allows userfaultfd monitor to perform user-space paging
> > for the child process.
> >
> > +Unlike page faults which have to be synchronous and require
> > +explicit or implicit wakeup,
> > +all other events are delivered asynchronously and
> > +the non-cooperative process resumes execution as
> > +soon as manager executes
> > +.BR read(2).
> > +The userfaultfd manager should carefully synchronize calls
> > +to UFFDIO_COPY with the events processing.
> > +
> > +The current asynchronous model of the event delivery is optimal for
> > +single threaded non-cooperative userfaultfd manager implementations.
>
> The preceding paragraph feels incomplete. It seems like you want to make
> a point with that last sentence, but the point is not explicit. What's
> missing?
I've copied both from Documentation/vm/userfaulftfd.txt, and there we also
talk about possibility of addition of synchronous events delivery and
that makes the paragraph above to seem crippled :)
The major point here is that current events delivery model could be
problematic for multi-threaded monitor. I even suspect that it would be
impossible to ensure synchronization between page faults and non-page
fault events in multi-threaded monitor.
> > +
> > .\" FIXME elaborate about non-cooperating mode, describe its limitations
> > .\" for kernels before 4.11, features added in 4.11
> > .\" and limitations remaining in 4.11
> >
>
> Cheers,
>
> Michael
>
>
>
> --
> Michael Kerrisk
> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
> Linux/UNIX System Programming Training: http://man7.org/training/
>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
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^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 0/5] {ioctl_}userfaultfd.2: yet another update
2017-05-01 18:34 ` Michael Kerrisk (man-pages)
@ 2017-05-02 9:48 ` Mike Rapoport
-1 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-02 9:48 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On Mon, May 01, 2017 at 08:34:07PM +0200, Michael Kerrisk (man-pages) wrote:
> Hi Mike,
>
> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> > Hi Michael,
> >
> > These updates pretty much complete the coverage of 4.11 additions, IMHO.
>
> Thanks for this, but we still await input from Andrea
> on various points.
>
> > Mike Rapoport (5):
> > ioctl_userfaultfd.2: update description of shared memory areas
> > ioctl_userfaultfd.2: UFFDIO_COPY: add ENOENT and ENOSPC description
> > ioctl_userfaultfd.2: add BUGS section
> > userfaultfd.2: add note about asynchronios events delivery
> > userfaultfd.2: update VERSIONS section with 4.11 chanegs
> >
> > man2/ioctl_userfaultfd.2 | 35 +++++++++++++++++++++++++++++++++--
> > man2/userfaultfd.2 | 15 +++++++++++++++
> > 2 files changed, 48 insertions(+), 2 deletions(-)
>
> I've applied all of the above, and done some light editing.
>
> Could you please check my changes in the following commits:
>
> 5191c68806c8ac73fdc89586cde434d2766abb5c
> 265225c1e2311ae26ead116e6c8d2cedd46144fa
Both are Ok
Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
> Thanks,
>
> Michael
>
> --
> Michael Kerrisk
> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
> Linux/UNIX System Programming Training: http://man7.org/training/
>
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 0/5] {ioctl_}userfaultfd.2: yet another update
@ 2017-05-02 9:48 ` Mike Rapoport
0 siblings, 0 replies; 41+ messages in thread
From: Mike Rapoport @ 2017-05-02 9:48 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On Mon, May 01, 2017 at 08:34:07PM +0200, Michael Kerrisk (man-pages) wrote:
> Hi Mike,
>
> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
> > Hi Michael,
> >
> > These updates pretty much complete the coverage of 4.11 additions, IMHO.
>
> Thanks for this, but we still await input from Andrea
> on various points.
>
> > Mike Rapoport (5):
> > ioctl_userfaultfd.2: update description of shared memory areas
> > ioctl_userfaultfd.2: UFFDIO_COPY: add ENOENT and ENOSPC description
> > ioctl_userfaultfd.2: add BUGS section
> > userfaultfd.2: add note about asynchronios events delivery
> > userfaultfd.2: update VERSIONS section with 4.11 chanegs
> >
> > man2/ioctl_userfaultfd.2 | 35 +++++++++++++++++++++++++++++++++--
> > man2/userfaultfd.2 | 15 +++++++++++++++
> > 2 files changed, 48 insertions(+), 2 deletions(-)
>
> I've applied all of the above, and done some light editing.
>
> Could you please check my changes in the following commits:
>
> 5191c68806c8ac73fdc89586cde434d2766abb5c
> 265225c1e2311ae26ead116e6c8d2cedd46144fa
Both are Ok
Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
> Thanks,
>
> Michael
>
> --
> Michael Kerrisk
> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
> Linux/UNIX System Programming Training: http://man7.org/training/
>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
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^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 1/5] ioctl_userfaultfd.2: update description of shared memory areas
2017-05-02 9:31 ` Mike Rapoport
@ 2017-05-02 20:23 ` Michael Kerrisk (man-pages)
-1 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-02 20:23 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On 05/02/2017 11:31 AM, Mike Rapoport wrote:
> On Mon, May 01, 2017 at 08:33:31PM +0200, Michael Kerrisk (man-pages) wrote:
>> Hello Mike,
>>
>> I've applied this patch, but have a question.
>>
>> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
>>> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
>>> ---
>>> man2/ioctl_userfaultfd.2 | 13 +++++++++++--
>>> 1 file changed, 11 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
>>> index 889feb9..6edd396 100644
>>> --- a/man2/ioctl_userfaultfd.2
>>> +++ b/man2/ioctl_userfaultfd.2
>>> @@ -181,8 +181,17 @@ virtual memory areas
>>> .TP
>>> .B UFFD_FEATURE_MISSING_SHMEM
>>> If this feature bit is set,
>>> -the kernel supports registering userfaultfd ranges on tmpfs
>>> -virtual memory areas
>>> +the kernel supports registering userfaultfd ranges on shared memory areas.
>>> +This includes all kernel shared memory APIs:
>>> +System V shared memory,
>>> +tmpfs,
>>> +/dev/zero,
>>> +.BR mmap(2)
>>> +with
>>> +.I MAP_SHARED
>>> +flag set,
>>> +.BR memfd_create (2),
>>> +etc.
>>>
>>> The returned
>>> .I ioctls
>>
>> Does the change in this patch represent a change that occurred in
>> Linux 4.11? If so, I think this needs to be said explicitly in the text.
>
> The patch only extends the description of UFFD_FEATURE_MISSING_SHMEM. The
> feature is indeed available from 4.11, but that is said a few lives above
> (line 136 in ioctl_userfaultfd.2)
Okay -- thanks for the clarification.
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 1/5] ioctl_userfaultfd.2: update description of shared memory areas
@ 2017-05-02 20:23 ` Michael Kerrisk (man-pages)
0 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-02 20:23 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On 05/02/2017 11:31 AM, Mike Rapoport wrote:
> On Mon, May 01, 2017 at 08:33:31PM +0200, Michael Kerrisk (man-pages) wrote:
>> Hello Mike,
>>
>> I've applied this patch, but have a question.
>>
>> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
>>> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
>>> ---
>>> man2/ioctl_userfaultfd.2 | 13 +++++++++++--
>>> 1 file changed, 11 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/man2/ioctl_userfaultfd.2 b/man2/ioctl_userfaultfd.2
>>> index 889feb9..6edd396 100644
>>> --- a/man2/ioctl_userfaultfd.2
>>> +++ b/man2/ioctl_userfaultfd.2
>>> @@ -181,8 +181,17 @@ virtual memory areas
>>> .TP
>>> .B UFFD_FEATURE_MISSING_SHMEM
>>> If this feature bit is set,
>>> -the kernel supports registering userfaultfd ranges on tmpfs
>>> -virtual memory areas
>>> +the kernel supports registering userfaultfd ranges on shared memory areas.
>>> +This includes all kernel shared memory APIs:
>>> +System V shared memory,
>>> +tmpfs,
>>> +/dev/zero,
>>> +.BR mmap(2)
>>> +with
>>> +.I MAP_SHARED
>>> +flag set,
>>> +.BR memfd_create (2),
>>> +etc.
>>>
>>> The returned
>>> .I ioctls
>>
>> Does the change in this patch represent a change that occurred in
>> Linux 4.11? If so, I think this needs to be said explicitly in the text.
>
> The patch only extends the description of UFFD_FEATURE_MISSING_SHMEM. The
> feature is indeed available from 4.11, but that is said a few lives above
> (line 136 in ioctl_userfaultfd.2)
Okay -- thanks for the clarification.
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
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^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 4/5] userfaultfd.2: add note about asynchronios events delivery
2017-05-02 9:46 ` Mike Rapoport
@ 2017-05-02 20:27 ` Michael Kerrisk (man-pages)
-1 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-02 20:27 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On 05/02/2017 11:46 AM, Mike Rapoport wrote:
> On Mon, May 01, 2017 at 08:33:45PM +0200, Michael Kerrisk (man-pages) wrote:
>> Hi Mike,
>>
>> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
>>> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
>>
>> Thanks. Applied. One question below.
>>
>>> ---
>>> man2/userfaultfd.2 | 12 ++++++++++++
>>> 1 file changed, 12 insertions(+)
>>>
>>> diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2
>>> index 8b89162..f177bba 100644
>>> --- a/man2/userfaultfd.2
>>> +++ b/man2/userfaultfd.2
>>> @@ -112,6 +112,18 @@ created for the child process,
>>> which allows userfaultfd monitor to perform user-space paging
>>> for the child process.
>>>
>>> +Unlike page faults which have to be synchronous and require
>>> +explicit or implicit wakeup,
>>> +all other events are delivered asynchronously and
>>> +the non-cooperative process resumes execution as
>>> +soon as manager executes
>>> +.BR read(2).
>>> +The userfaultfd manager should carefully synchronize calls
>>> +to UFFDIO_COPY with the events processing.
>>> +
>>> +The current asynchronous model of the event delivery is optimal for
>>> +single threaded non-cooperative userfaultfd manager implementations.
>>
>> The preceding paragraph feels incomplete. It seems like you want to make
>> a point with that last sentence, but the point is not explicit. What's
>> missing?
>
> I've copied both from Documentation/vm/userfaulftfd.txt, and there we also
> talk about possibility of addition of synchronous events delivery and
> that makes the paragraph above to seem crippled :)
> The major point here is that current events delivery model could be
> problematic for multi-threaded monitor. I even suspect that it would be
> impossible to ensure synchronization between page faults and non-page
> fault events in multi-threaded monitor.
Okay -- thanks for the info. I've noted it, but won't make changes
any changes to the page for now.
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 4/5] userfaultfd.2: add note about asynchronios events delivery
@ 2017-05-02 20:27 ` Michael Kerrisk (man-pages)
0 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-02 20:27 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On 05/02/2017 11:46 AM, Mike Rapoport wrote:
> On Mon, May 01, 2017 at 08:33:45PM +0200, Michael Kerrisk (man-pages) wrote:
>> Hi Mike,
>>
>> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
>>> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
>>
>> Thanks. Applied. One question below.
>>
>>> ---
>>> man2/userfaultfd.2 | 12 ++++++++++++
>>> 1 file changed, 12 insertions(+)
>>>
>>> diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2
>>> index 8b89162..f177bba 100644
>>> --- a/man2/userfaultfd.2
>>> +++ b/man2/userfaultfd.2
>>> @@ -112,6 +112,18 @@ created for the child process,
>>> which allows userfaultfd monitor to perform user-space paging
>>> for the child process.
>>>
>>> +Unlike page faults which have to be synchronous and require
>>> +explicit or implicit wakeup,
>>> +all other events are delivered asynchronously and
>>> +the non-cooperative process resumes execution as
>>> +soon as manager executes
>>> +.BR read(2).
>>> +The userfaultfd manager should carefully synchronize calls
>>> +to UFFDIO_COPY with the events processing.
>>> +
>>> +The current asynchronous model of the event delivery is optimal for
>>> +single threaded non-cooperative userfaultfd manager implementations.
>>
>> The preceding paragraph feels incomplete. It seems like you want to make
>> a point with that last sentence, but the point is not explicit. What's
>> missing?
>
> I've copied both from Documentation/vm/userfaulftfd.txt, and there we also
> talk about possibility of addition of synchronous events delivery and
> that makes the paragraph above to seem crippled :)
> The major point here is that current events delivery model could be
> problematic for multi-threaded monitor. I even suspect that it would be
> impossible to ensure synchronization between page faults and non-page
> fault events in multi-threaded monitor.
Okay -- thanks for the info. I've noted it, but won't make changes
any changes to the page for now.
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
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^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 0/5] {ioctl_}userfaultfd.2: yet another update
2017-05-02 9:48 ` Mike Rapoport
(?)
@ 2017-05-02 20:28 ` Michael Kerrisk (man-pages)
-1 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-02 20:28 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On 05/02/2017 11:48 AM, Mike Rapoport wrote:
> On Mon, May 01, 2017 at 08:34:07PM +0200, Michael Kerrisk (man-pages) wrote:
>> Hi Mike,
>>
>> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
>>> Hi Michael,
>>>
>>> These updates pretty much complete the coverage of 4.11 additions, IMHO.
>>
>> Thanks for this, but we still await input from Andrea
>> on various points.
>>
>>> Mike Rapoport (5):
>>> ioctl_userfaultfd.2: update description of shared memory areas
>>> ioctl_userfaultfd.2: UFFDIO_COPY: add ENOENT and ENOSPC description
>>> ioctl_userfaultfd.2: add BUGS section
>>> userfaultfd.2: add note about asynchronios events delivery
>>> userfaultfd.2: update VERSIONS section with 4.11 chanegs
>>>
>>> man2/ioctl_userfaultfd.2 | 35 +++++++++++++++++++++++++++++++++--
>>> man2/userfaultfd.2 | 15 +++++++++++++++
>>> 2 files changed, 48 insertions(+), 2 deletions(-)
>>
>> I've applied all of the above, and done some light editing.
>>
>> Could you please check my changes in the following commits:
>>
>> 5191c68806c8ac73fdc89586cde434d2766abb5c
>> 265225c1e2311ae26ead116e6c8d2cedd46144fa
>
> Both are Ok
> Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Thanks for checking, Mike.
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 0/5] {ioctl_}userfaultfd.2: yet another update
@ 2017-05-02 20:28 ` Michael Kerrisk (man-pages)
0 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-02 20:28 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w, Andrea Arcangeli,
linux-kernel-u79uwXL29TY76Z2rM5mHXA,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg,
linux-man-u79uwXL29TY76Z2rM5mHXA
On 05/02/2017 11:48 AM, Mike Rapoport wrote:
> On Mon, May 01, 2017 at 08:34:07PM +0200, Michael Kerrisk (man-pages) wrote:
>> Hi Mike,
>>
>> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
>>> Hi Michael,
>>>
>>> These updates pretty much complete the coverage of 4.11 additions, IMHO.
>>
>> Thanks for this, but we still await input from Andrea
>> on various points.
>>
>>> Mike Rapoport (5):
>>> ioctl_userfaultfd.2: update description of shared memory areas
>>> ioctl_userfaultfd.2: UFFDIO_COPY: add ENOENT and ENOSPC description
>>> ioctl_userfaultfd.2: add BUGS section
>>> userfaultfd.2: add note about asynchronios events delivery
>>> userfaultfd.2: update VERSIONS section with 4.11 chanegs
>>>
>>> man2/ioctl_userfaultfd.2 | 35 +++++++++++++++++++++++++++++++++--
>>> man2/userfaultfd.2 | 15 +++++++++++++++
>>> 2 files changed, 48 insertions(+), 2 deletions(-)
>>
>> I've applied all of the above, and done some light editing.
>>
>> Could you please check my changes in the following commits:
>>
>> 5191c68806c8ac73fdc89586cde434d2766abb5c
>> 265225c1e2311ae26ead116e6c8d2cedd46144fa
>
> Both are Ok
> Reviewed-by: Mike Rapoport <rppt-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
Thanks for checking, Mike.
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
To unsubscribe from this list: send the line "unsubscribe linux-man" in
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More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 41+ messages in thread
* Re: [PATCH man-pages 0/5] {ioctl_}userfaultfd.2: yet another update
@ 2017-05-02 20:28 ` Michael Kerrisk (man-pages)
0 siblings, 0 replies; 41+ messages in thread
From: Michael Kerrisk (man-pages) @ 2017-05-02 20:28 UTC (permalink / raw)
To: Mike Rapoport
Cc: mtk.manpages, Andrea Arcangeli, linux-kernel, linux-mm, linux-man
On 05/02/2017 11:48 AM, Mike Rapoport wrote:
> On Mon, May 01, 2017 at 08:34:07PM +0200, Michael Kerrisk (man-pages) wrote:
>> Hi Mike,
>>
>> On 05/01/2017 07:43 AM, Mike Rapoport wrote:
>>> Hi Michael,
>>>
>>> These updates pretty much complete the coverage of 4.11 additions, IMHO.
>>
>> Thanks for this, but we still await input from Andrea
>> on various points.
>>
>>> Mike Rapoport (5):
>>> ioctl_userfaultfd.2: update description of shared memory areas
>>> ioctl_userfaultfd.2: UFFDIO_COPY: add ENOENT and ENOSPC description
>>> ioctl_userfaultfd.2: add BUGS section
>>> userfaultfd.2: add note about asynchronios events delivery
>>> userfaultfd.2: update VERSIONS section with 4.11 chanegs
>>>
>>> man2/ioctl_userfaultfd.2 | 35 +++++++++++++++++++++++++++++++++--
>>> man2/userfaultfd.2 | 15 +++++++++++++++
>>> 2 files changed, 48 insertions(+), 2 deletions(-)
>>
>> I've applied all of the above, and done some light editing.
>>
>> Could you please check my changes in the following commits:
>>
>> 5191c68806c8ac73fdc89586cde434d2766abb5c
>> 265225c1e2311ae26ead116e6c8d2cedd46144fa
>
> Both are Ok
> Reviewed-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Thanks for checking, Mike.
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 41+ messages in thread
end of thread, other threads:[~2017-05-02 20:29 UTC | newest]
Thread overview: 41+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-05-01 5:43 [PATCH man-pages 0/5] {ioctl_}userfaultfd.2: yet another update Mike Rapoport
2017-05-01 5:43 ` Mike Rapoport
2017-05-01 5:43 ` [PATCH man-pages 1/5] ioctl_userfaultfd.2: update description of shared memory areas Mike Rapoport
2017-05-01 5:43 ` Mike Rapoport
2017-05-01 18:33 ` Michael Kerrisk (man-pages)
2017-05-01 18:33 ` Michael Kerrisk (man-pages)
2017-05-02 9:31 ` Mike Rapoport
2017-05-02 9:31 ` Mike Rapoport
2017-05-02 9:31 ` Mike Rapoport
2017-05-02 20:23 ` Michael Kerrisk (man-pages)
2017-05-02 20:23 ` Michael Kerrisk (man-pages)
2017-05-01 5:43 ` [PATCH man-pages 2/5] ioctl_userfaultfd.2: UFFDIO_COPY: add ENOENT and ENOSPC description Mike Rapoport
2017-05-01 5:43 ` Mike Rapoport
2017-05-01 18:33 ` Michael Kerrisk (man-pages)
2017-05-01 18:33 ` Michael Kerrisk (man-pages)
2017-05-01 5:43 ` [PATCH man-pages 3/5] ioctl_userfaultfd.2: add BUGS section Mike Rapoport
2017-05-01 5:43 ` Mike Rapoport
2017-05-01 18:33 ` Michael Kerrisk (man-pages)
2017-05-01 18:33 ` Michael Kerrisk (man-pages)
2017-05-02 9:32 ` Mike Rapoport
2017-05-02 9:32 ` Mike Rapoport
2017-05-02 9:32 ` Mike Rapoport
2017-05-01 5:43 ` [PATCH man-pages 4/5] userfaultfd.2: add note about asynchronios events delivery Mike Rapoport
2017-05-01 5:43 ` Mike Rapoport
2017-05-01 18:33 ` Michael Kerrisk (man-pages)
2017-05-01 18:33 ` Michael Kerrisk (man-pages)
2017-05-02 9:46 ` Mike Rapoport
2017-05-02 9:46 ` Mike Rapoport
2017-05-02 20:27 ` Michael Kerrisk (man-pages)
2017-05-02 20:27 ` Michael Kerrisk (man-pages)
2017-05-01 5:43 ` [PATCH man-pages 5/5] userfaultfd.2: update VERSIONS section with 4.11 chanegs Mike Rapoport
2017-05-01 5:43 ` Mike Rapoport
2017-05-01 18:33 ` Michael Kerrisk (man-pages)
2017-05-01 18:33 ` Michael Kerrisk (man-pages)
2017-05-01 18:34 ` [PATCH man-pages 0/5] {ioctl_}userfaultfd.2: yet another update Michael Kerrisk (man-pages)
2017-05-01 18:34 ` Michael Kerrisk (man-pages)
2017-05-02 9:48 ` Mike Rapoport
2017-05-02 9:48 ` Mike Rapoport
2017-05-02 20:28 ` Michael Kerrisk (man-pages)
2017-05-02 20:28 ` Michael Kerrisk (man-pages)
2017-05-02 20:28 ` Michael Kerrisk (man-pages)
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