and sub-buffers.
Also update the ring-buffer map_test to verify that padding.
Signed-off-by: Vincent Donnefort
--
This is based on the mm-unstable branch [1] as it depends on David's work [2]
for allowing the zero-page in vm_insert_page().
[1] https://git.kernel.org/pub/scm/linux/kernel/git/akpm
It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.
Signed-off-by: Vincent Donnefort
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index 5092d6c13af5..0b300901fd75 100644
--- a/Documentation/trace/index.rst
L_GET_READER. This will update the Meta-page reader ID to
point to the next reader containing unread data.
Mapping will prevent snapshot and buffer size modifications.
CC:
Signed-off-by: Vincent Donnefort
diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h
index
during the
first mapping.
Once mapped, no subbuf can get in or out of the ring-buffer: the buffer
size will remain unmodified and the splice enabling functions will in
reality simply memcpy the data instead of swapping subbufs.
CC:
Signed-off-by: Vincent Donnefort
diff --git a/include/linux
In preparation for the ring-buffer memory mapping, allocate compound
pages for the ring-buffer sub-buffers to enable us to map them to
user-space with vm_insert_pages().
Acked-by: David Hildenbrand
Signed-off-by: Vincent Donnefort
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace
uffer_meta_header
v1 -> v2:
* Hide data_pages from the userspace struct
* Fix META_PAGE_MAX_PAGES
* Support for order > 0 meta-page
* Add missing page->mapping.
Vincent Donnefort (5):
ring-buffer: Allocate sub-buffers with __GFP_COMP
ring-buffer: Introducing ring-buffer mapping fun
[...]
> > > +
> > > + while (s < nr_subbufs && p < nr_pages) {
> > > + struct page *page = virt_to_page(cpu_buffer->subbuf_ids[s]);
> > > + int off = 0;
> > > +
> > > + for (; off < (1 << (subbuf_order)); off++, page++) {
> > > + if (p >= nr_pages)
> > > +
On Fri, May 10, 2024 at 11:15:59AM +0200, David Hildenbrand wrote:
> On 09.05.24 13:05, Vincent Donnefort wrote:
> > On Tue, May 07, 2024 at 10:34:02PM -0400, Steven Rostedt wrote:
> > > On Tue, 30 Apr 2024 12:13:51 +0100
> > > Vincent Donnefort wrote:
> &
On Tue, May 07, 2024 at 10:34:02PM -0400, Steven Rostedt wrote:
> On Tue, 30 Apr 2024 12:13:51 +0100
> Vincent Donnefort wrote:
>
> > +#ifdef CONFIG_MMU
> > +static int __rb_map_vma(struct ring_buffer_per_cpu *cpu_buffer,
> > +
On Thu, May 02, 2024 at 03:30:32PM +0200, David Hildenbrand wrote:
> On 30.04.24 13:13, Vincent Donnefort wrote:
> > In preparation for allowing the user-space to map a ring-buffer, add
> > a set of mapping functions:
> >
> >ring_buffer_{map,unmap}()
> >
&g
It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.
Signed-off-by: Vincent Donnefort
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index 5092d6c13af5..0b300901fd75 100644
--- a/Documentation/trace/index.rst
L_GET_READER. This will update the Meta-page reader ID to
point to the next reader containing unread data.
Mapping will prevent snapshot and buffer size modifications.
CC:
Signed-off-by: Vincent Donnefort
diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h
index
during the
first mapping.
Once mapped, no subbuf can get in or out of the ring-buffer: the buffer
size will remain unmodified and the splice enabling functions will in
reality simply memcpy the data instead of swapping subbufs.
CC:
Signed-off-by: Vincent Donnefort
diff --git a/include/linux
In preparation for the ring-buffer memory mapping, allocate compound
pages for the ring-buffer sub-buffers to enable us to map them to
user-space with vm_insert_pages().
Signed-off-by: Vincent Donnefort
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 25476ead681b
page field ->read
* Rename ring_buffer_meta_page_header into ring_buffer_meta_header
v1 -> v2:
* Hide data_pages from the userspace struct
* Fix META_PAGE_MAX_PAGES
* Support for order > 0 meta-page
* Add missing page->mapping.
Vincent Donnefort (5):
ring-buffer: Allocate sub-
On Wed, Apr 24, 2024 at 10:55:54PM +0200, David Hildenbrand wrote:
> On 24.04.24 22:31, Vincent Donnefort wrote:
> > Hi David,
> >
> > Thanks for your quick response.
> >
> > On Wed, Apr 24, 2024 at 05:26:39PM +0200, David Hildenbrand wrote:
> > >
>
Hi David,
Thanks for your quick response.
On Wed, Apr 24, 2024 at 05:26:39PM +0200, David Hildenbrand wrote:
>
> I gave it some more thought, and I think we are still missing something (I
> wish PFNMAP/MIXEDMAP wouldn't be that hard).
>
> > +
> > +/*
> > + * +--+ pgoff == 0
> >
It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.
Signed-off-by: Vincent Donnefort
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index 5092d6c13af5..0b300901fd75 100644
--- a/Documentation/trace/index.rst
L_GET_READER. This will update the Meta-page reader ID to
point to the next reader containing unread data.
Mapping will prevent snapshot and buffer size modifications.
CC:
Signed-off-by: Vincent Donnefort
diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h
index
during the
first mapping.
Once mapped, no subbuf can get in or out of the ring-buffer: the buffer
size will remain unmodified and the splice enabling functions will in
reality simply memcpy the data instead of swapping subbufs.
CC:
Signed-off-by: Vincent Donnefort
diff --git a/include/linux
In preparation for the ring-buffer memory mapping, allocate compound
pages for the ring-buffer sub-buffers to enable us to map them to
user-space with vm_insert_pages().
Signed-off-by: Vincent Donnefort
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 25476ead681b
> 0 meta-page
* Add a new meta page field ->read
* Rename ring_buffer_meta_page_header into ring_buffer_meta_header
v1 -> v2:
* Hide data_pages from the userspace struct
* Fix META_PAGE_MAX_PAGES
* Support for order > 0 meta-page
* Add missing page->mapping.
Vincent Donnefor
On Mon, Apr 22, 2024 at 08:27:17PM +0200, David Hildenbrand wrote:
> On 22.04.24 20:20, Vincent Donnefort wrote:
> > Hi David,
> >
> > Thanks for having a look, very much appreciated!
> >
> > On Mon, Apr 22, 2024 at 11:27:11AM +0200, David Hildenbrand wrot
Hi David,
Thanks for having a look, very much appreciated!
On Mon, Apr 22, 2024 at 11:27:11AM +0200, David Hildenbrand wrote:
> On 19.04.24 20:25, David Hildenbrand wrote:
> > On 06.04.24 19:36, Vincent Donnefort wrote:
> > > In preparation for allowing the user-space to map
On Thu, Apr 18, 2024 at 11:43:46PM -0400, Steven Rostedt wrote:
> On Thu, 18 Apr 2024 09:55:55 +0300
> Mike Rapoport wrote:
>
> Hi Mike,
>
> Thanks for doing this review!
>
> > > +/**
> > > + * struct trace_buffer_meta - Ring-buffer Meta-page description
> > > + * @meta_page_size: Size of
On Wed, Apr 10, 2024 at 09:25:42PM -0400, Steven Rostedt wrote:
> From: "Steven Rostedt (Google)"
>
> In preparation for having the ring buffer mapped to a dedicated location,
> which will have the same restrictions as user space memory mapped buffers,
> allow it to use the "mapped" field of the
It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.
Signed-off-by: Vincent Donnefort
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index 5092d6c13af5..0b300901fd75 100644
--- a/Documentation/trace/index.rst
L_GET_READER. This will update the Meta-page reader ID to
point to the next reader containing unread data.
Mapping will prevent snapshot and buffer size modifications.
CC:
Signed-off-by: Vincent Donnefort
diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h
index
during the
first mapping.
Once mapped, no subbuf can get in or out of the ring-buffer: the buffer
size will remain unmodified and the splice enabling functions will in
reality simply memcpy the data instead of swapping subbufs.
CC:
Signed-off-by: Vincent Donnefort
diff --git a/include/linux
In preparation for the ring-buffer memory mapping, allocate compound
pages for the ring-buffer sub-buffers to enable us to map them to
user-space with vm_insert_pages().
Signed-off-by: Vincent Donnefort
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 25476ead681b
ove data page list (for non-consuming read)
** Implies removing order > 0 meta-page
* Add a new meta page field ->read
* Rename ring_buffer_meta_page_header into ring_buffer_meta_header
v1 -> v2:
* Hide data_pages from the userspace struct
* Fix META_PAGE_MAX_PAGES
* Supp
On Wed, Apr 03, 2024 at 10:13:52AM -0400, Steven Rostedt wrote:
> On Fri, 29 Mar 2024 14:40:55 -0400
> Steven Rostedt wrote:
>
> > > +static vm_fault_t tracing_buffers_mmap_fault(struct vm_fault *vmf)
> > > +{
> > > + return VM_FAULT_SIGBUS;
> > > +}
> >
> > If this is all it does, I don't
It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.
Signed-off-by: Vincent Donnefort
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index 5092d6c13af5..0b300901fd75 100644
--- a/Documentation/trace/index.rst
L_GET_READER. This will update the Meta-page reader ID to
point to the next reader containing unread data.
Mapping will prevent snapshot and buffer size modifications.
CC:
Signed-off-by: Vincent Donnefort
diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h
index
during the
first mapping.
Once mapped, no subbuf can get in or out of the ring-buffer: the buffer
size will remain unmodified and the splice enabling functions will in
reality simply memcpy the data instead of swapping subbufs.
CC:
Signed-off-by: Vincent Donnefort
diff --git a/include/linux
In preparation for the ring-buffer memory mapping, allocate compound
pages for the ring-buffer sub-buffers to enable us to map them to
user-space with vm_insert_pages().
Signed-off-by: Vincent Donnefort
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 25476ead681b
e ring_buffer_meta_page_header into ring_buffer_meta_header
v1 -> v2:
* Hide data_pages from the userspace struct
* Fix META_PAGE_MAX_PAGES
* Support for order > 0 meta-page
* Add missing page->mapping.
Vincent Donnefort (5):
ring-buffer: allocate sub-buffers with __GFP_COMP
rin
It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.
Signed-off-by: Vincent Donnefort
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index 5092d6c13af5..0b300901fd75 100644
--- a/Documentation/trace/index.rst
L_GET_READER. This will update the Meta-page reader ID to
point to the next reader containing unread data.
Mapping will prevent snapshot and buffer size modifications.
Signed-off-by: Vincent Donnefort
diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h
index
during the
first mapping.
Once mapped, no subbuf can get in or out of the ring-buffer: the buffer
size will remain unmodified and the splice enabling functions will in
reality simply memcpy the data instead of swapping subbufs.
Signed-off-by: Vincent Donnefort
diff --git a/include/linux
In preparation for the ring-buffer memory mapping, allocate compound
pages for the ring-buffer sub-buffers to enable us to map them to
user-space with vm_insert_pages().
Signed-off-by: Vincent Donnefort
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 25476ead681b
e ring_buffer_meta_page_header into ring_buffer_meta_header
v1 -> v2:
* Hide data_pages from the userspace struct
* Fix META_PAGE_MAX_PAGES
* Support for order > 0 meta-page
* Add missing page->mapping.
Vincent Donnefort (5):
ring-buffer: allocate sub-buffers with __GFP_COMP
rin
It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.
Signed-off-by: Vincent Donnefort
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index 5092d6c13af5..0b300901fd75 100644
--- a/Documentation/trace/index.rst
trace_types_lock, a new spinlock is
introduced to serialize accesses to trace_array->snapshot. This intends
to allow access to that variable in a context where the mmap lock is
already held.
Signed-off-by: Vincent Donnefort
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8198bfc54
L_GET_READER. This will update the Meta-page reader ID to
point to the next reader containing unread data.
Mapping will prevent snapshot and buffer size modifications.
Signed-off-by: Vincent Donnefort
diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h
index
their unique ID, assigned during the
first mapping.
Once mapped, no subbuf can get in or out of the ring-buffer: the buffer
size will remain unmodified and the splice enabling functions will in
reality simply memcpy the data instead of swapping subbufs.
Signed-off-by: Vincent Donnefort
diff
In preparation for the ring-buffer memory mapping where each subbuf will
be accessible to user-space, zero all the page allocations.
Signed-off-by: Vincent Donnefort
Reviewed-by: Masami Hiramatsu (Google)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index fd4bfe3ecf01
lies removing order > 0 meta-page
* Add a new meta page field ->read
* Rename ring_buffer_meta_page_header into ring_buffer_meta_header
v1 -> v2:
* Hide data_pages from the userspace struct
* Fix META_PAGE_MAX_PAGES
* Support for order > 0 meta-page
* Add missing page->mapping.
Vincent D
It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.
Signed-off-by: Vincent Donnefort
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index 5092d6c13af5..0b300901fd75 100644
--- a/Documentation/trace/index.rst
L_GET_READER. This will update the Meta-page reader ID to
point to the next reader containing unread data.
Mapping will prevent snapshot and buffer size modifications.
Signed-off-by: Vincent Donnefort
diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h
index
trace_types_lock, a new spinlock is
introduced to serialize accesses to trace_array->snapshot. This intends
to allow access to that variable in a context where the mmap lock is
already held.
Signed-off-by: Vincent Donnefort
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2a7c6fd93
their unique ID, assigned during the
first mapping.
Once mapped, no subbuf can get in or out of the ring-buffer: the buffer
size will remain unmodified and the splice enabling functions will in
reality simply memcpy the data instead of swapping subbufs.
Signed-off-by: Vincent Donnefort
diff
In preparation for the ring-buffer memory mapping where each subbuf will
be accessible to user-space, zero all the page allocations.
Signed-off-by: Vincent Donnefort
Reviewed-by: Masami Hiramatsu (Google)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index fd4bfe3ecf01
_buffer_meta_header
v1 -> v2:
* Hide data_pages from the userspace struct
* Fix META_PAGE_MAX_PAGES
* Support for order > 0 meta-page
* Add missing page->mapping.
Vincent Donnefort (6):
ring-buffer: Zero ring-buffer sub-buffers
ring-buffer: Introducing ring-buffer mapping func
[...]
> > +static void rb_update_meta_page(struct ring_buffer_per_cpu *cpu_buffer)
> > +{
> > + struct trace_buffer_meta *meta = cpu_buffer->meta_page;
> > +
> > + meta->reader.read = cpu_buffer->reader_page->read;
> > + meta->reader.id = cpu_buffer->reader_page->id;
> > +
It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.
Signed-off-by: Vincent Donnefort
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index 5092d6c13af5..0b300901fd75 100644
--- a/Documentation/trace/index.rst
L_GET_READER. This will update the Meta-page reader ID to
point to the next reader containing unread data.
Mapping will prevent snapshot and buffer size modifications.
Signed-off-by: Vincent Donnefort
diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h
index
trace_types_lock, a new spinlock is
introduced to serialize accesses to trace_array->snapshot. This intends
to allow access to that variable in a context where the mmap lock is
already held.
Signed-off-by: Vincent Donnefort
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2a7c6fd93
their unique ID, assigned during the
first mapping.
Once mapped, no subbuf can get in or out of the ring-buffer: the buffer
size will remain unmodified and the splice enabling functions will in
reality simply memcpy the data instead of swapping subbufs.
Signed-off-by: Vincent Donnefort
diff
In preparation for the ring-buffer memory mapping where each subbuf will
be accessible to user-space, zero all the page allocations.
Signed-off-by: Vincent Donnefort
Reviewed-by: Masami Hiramatsu (Google)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index fd4bfe3ecf01
GE_MAX_PAGES
* Support for order > 0 meta-page
* Add missing page->mapping.
Vincent Donnefort (6):
ring-buffer: Zero ring-buffer sub-buffers
ring-buffer: Introducing ring-buffer mapping functions
tracing: Add snapshot refcount
tracing: Allow user-space mapping of the ring-buffe
It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.
Signed-off-by: Vincent Donnefort
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index 5092d6c13af5..0b300901fd75 100644
--- a/Documentation/trace/index.rst
L_GET_READER. This will update the Meta-page reader ID to
point to the next reader containing unread data.
Mapping will prevent snapshot and buffer size modifications.
Signed-off-by: Vincent Donnefort
diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h
index
trace_types_lock, a new spinlock is
introduced to serialize accesses to trace_array->snapshot. This intends
to allow access to that variable in a context where the mmap lock is
already held.
Signed-off-by: Vincent Donnefort
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2a7c6fd93
their unique ID, assigned during the
first mapping.
Once mapped, no subbuf can get in or out of the ring-buffer: the buffer
size will remain unmodified and the splice enabling functions will in
reality simply memcpy the data instead of swapping subbufs.
Signed-off-by: Vincent Donnefort
diff
In preparation for the ring-buffer memory mapping where each subbuf will
be accessible to user-space, zero all the page allocations.
Signed-off-by: Vincent Donnefort
Reviewed-by: Masami Hiramatsu (Google)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index fd4bfe3ecf01
rder > 0 meta-page
* Add a new meta page field ->read
* Rename ring_buffer_meta_page_header into ring_buffer_meta_header
v1 -> v2:
* Hide data_pages from the userspace struct
* Fix META_PAGE_MAX_PAGES
* Support for order > 0 meta-page
* Add missing page->mapping.
Vincent Donnefort (6):
On Mon, Feb 05, 2024 at 01:44:47PM -0500, Mathieu Desnoyers wrote:
> On 2024-02-05 13:34, Vincent Donnefort wrote:
> > On Mon, Feb 05, 2024 at 11:55:08AM -0500, Mathieu Desnoyers wrote:
> [...]
>
> > >
> > > How are the kernel linear mapping and th
On Mon, Feb 05, 2024 at 11:55:08AM -0500, Mathieu Desnoyers wrote:
> On 2024-02-05 11:34, Vincent Donnefort wrote:
> > Currently, user-space extracts data from the ring-buffer via splice,
> > which is handy for storage or network sharing. However, due to splice
> > limitat
It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.
Signed-off-by: Vincent Donnefort
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index 5092d6c13af5..0b300901fd75 100644
--- a/Documentation/trace/index.rst
L_GET_READER. This will update the Meta-page reader ID to
point to the next reader containing unread data.
Mapping will prevent snapshot and buffer size modifications.
Signed-off-by: Vincent Donnefort
diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h
index
trace_types_lock, a new spinlock is
introduced to serialize accesses to trace_array->snapshot. This intends
to allow access to that variable in a context where the mmap lock is
already held.
Signed-off-by: Vincent Donnefort
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2a7c6fd93
their unique ID, assigned during the
first mapping.
Once mapped, no subbuf can get in or out of the ring-buffer: the buffer
size will remain unmodified and the splice enabling functions will in
reality simply memcpy the data instead of swapping subbufs.
Signed-off-by: Vincent Donnefort
diff
In preparation for the ring-buffer memory mapping where each subbuf will
be accessible to user-space, zero all the page allocations.
Signed-off-by: Vincent Donnefort
Reviewed-by: Masami Hiramatsu (Google)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index fd4bfe3ecf01
_PAGES
* Support for order > 0 meta-page
* Add missing page->mapping.
Vincent Donnefort (6):
ring-buffer: Zero ring-buffer sub-buffers
ring-buffer: Introducing ring-buffer mapping functions
tracing: Add snapshot refcount
tracing: Allow user-space mapping of the ring-buffer
Documenta
On Sat, Feb 03, 2024 at 07:33:51PM -0500, Steven Rostedt wrote:
> On Mon, 29 Jan 2024 14:27:58 +
> Vincent Donnefort wrote:
>
> > --- /dev/null
> > +++ b/include/uapi/linux/trace_mmap.h
> > @@ -0,0 +1,43 @@
> > +/* SPDX-License-Identifier: GPL-2.0 WITH L
at least is aware something went wrong.
Nonetheless, this is an incorrect code. Replace that -EINVAL with a
proper EPOLLERR to clean that output. As this doesn't change the
behaviour, there's no need to treat this change as a bug fix.
Signed-off-by: Vincent Donnefort
diff --git a/kernel/trace
On Tue, Jan 30, 2024 at 11:55:10PM +0900, Masami Hiramatsu wrote:
> Hi Vincent,
>
> Thanks for update the code.
>
> On Mon, 29 Jan 2024 14:27:58 +
> Vincent Donnefort wrote:
>
> > In preparation for allowing the user-space to map a ring-buffer, add
>
On Tue, Jan 30, 2024 at 05:30:38PM +0800, kernel test robot wrote:
> Hi Vincent,
>
> kernel test robot noticed the following build errors:
>
> [auto build test ERROR on 29142dc92c37d3259a33aef15b03e6ee25b0d188]
>
> url:
> https://github.com/intel-lab-lkp/linux/commit
It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.
Signed-off-by: Vincent Donnefort
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index 5092d6c13af5..0b300901fd75 100644
--- a/Documentation/trace/index.rst
L_GET_READER. This will update the Meta-page reader ID to
point to the next reader containing unread data.
Signed-off-by: Vincent Donnefort
diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h
index d4bb67430719..47194c51a4ac 100644
--- a/include/uapi/linux/trace_mmap.h
+
When a ring-buffer is memory mapped by user-space, no trace or
ring-buffer swap is possible. This means the snapshot feature is
mutually exclusive with the memory mapping. Having a refcount on
snapshot users will help to know if a mapping is possible or not.
Signed-off-by: Vincent Donnefort
their unique ID, assigned during the
first mapping.
Once mapped, no subbuf can get in or out of the ring-buffer: the buffer
size will remain unmodified and the splice enabling functions will in
reality simply memcpy the data instead of swapping subbufs.
Signed-off-by: Vincent Donnefort
diff
In preparation for the ring-buffer memory mapping where each subbuf will
be accessible to user-space, zero all the page allocations.
Signed-off-by: Vincent Donnefort
Reviewed-by: Masami Hiramatsu (Google)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 13aaf5e85b81
g read)
** Implies removing order > 0 meta-page
* Add a new meta page field ->read
* Rename ring_buffer_meta_page_header into ring_buffer_meta_header
v1 -> v2:
* Hide data_pages from the userspace struct
* Fix META_PAGE_MAX_PAGES
* Support for order > 0 meta-page
* Add missing
Hi Masami,
Thanks for taking the time to look at those changes.
On Thu, Jan 25, 2024 at 12:11:49AM +0900, Masami Hiramatsu wrote:
> On Tue, 23 Jan 2024 11:07:54 +
> Vincent Donnefort wrote:
>
> [...]
> > @@ -6592,8 +6641,11 @@ int tracing_set_tracer(struct trace_array *t
On Tue, Jan 23, 2024 at 10:51:49AM -0500, Steven Rostedt wrote:
> On Tue, 23 Jan 2024 11:07:53 +
> Vincent Donnefort wrote:
>
> > index ..5468afc94be7
> > --- /dev/null
> > +++ b/include/uapi/linux/trace_mmap.h
> > @@ -0,0 +1,44 @@
> &g
It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.
Signed-off-by: Vincent Donnefort
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index 5092d6c13af5..0b300901fd75 100644
--- a/Documentation/trace/index.rst
L_GET_READER. This will update the Meta-page reader ID to
point to the next reader containing unread data.
Signed-off-by: Vincent Donnefort
diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h
index 5468afc94be7..09c4ae6d6e71 100644
--- a/include/uapi/linux/trace_mmap.h
+
When a ring-buffer is memory mapped by user-space, no trace or
ring-buffer swap is possible. This means the snapshot feature is
mutually exclusive with the memory mapping. Having a refcount on
snapshot users will help to know if a mapping is possible or not.
Signed-off-by: Vincent Donnefort
their unique ID, assigned during the
first mapping.
Once mapped, no subbuf can get in or out of the ring-buffer: the buffer
size will remain unmodified and the splice enabling functions will in
reality simply memcpy the data instead of swapping subbufs.
Signed-off-by: Vincent Donnefort
diff
In preparation for the ring-buffer memory mapping where each subbuf will
be accessible to user-space, zero all the page allocations.
Signed-off-by: Vincent Donnefort
Reviewed-by: Masami Hiramatsu (Google)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 173d2595ce2d
* Remove data page list (for non-consuming read)
** Implies removing order > 0 meta-page
* Add a new meta page field ->read
* Rename ring_buffer_meta_page_header into ring_buffer_meta_header
v1 -> v2:
* Hide data_pages from the userspace struct
* Fix META_PAGE_MAX_PAGES
* Support for or
On Mon, Jan 15, 2024 at 11:23:59AM -0500, Steven Rostedt wrote:
> On Mon, 15 Jan 2024 11:09:38 -0500
> Steven Rostedt wrote:
>
> > No. The ring buffer logic should not care if the user of it is swapping
> > the entire ring buffer or not. It only cares if parts of the ring
> > buffer is being
On Mon, Jan 15, 2024 at 01:43:03PM +0900, Masami Hiramatsu wrote:
> On Thu, 11 Jan 2024 16:17:09 +
> Vincent Donnefort wrote:
>
> > In preparation for allowing the user-space to map a ring-buffer, add
> > a set of mapping functions:
> >
&
On Thu, Jan 11, 2024 at 06:23:20PM -0500, Steven Rostedt wrote:
> On Thu, 11 Jan 2024 11:34:58 -0500
> Mathieu Desnoyers wrote:
>
>
> > The LTTng kernel tracer has supported mmap'd buffers for nearly 15 years
> > [1],
> > and has a lot of similarities with this patch series.
> >
> > LTTng has
It is now possible to mmap() a ring-buffer to stream its content. Add
some documentation and a code example.
Signed-off-by: Vincent Donnefort
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index 5092d6c13af5..0b300901fd75 100644
--- a/Documentation/trace/index.rst
L_GET_READER. This will update the Meta-page reader ID to
point to the next reader containing unread data.
Signed-off-by: Vincent Donnefort
diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mmap.h
index bde39a73ce65..a797891e3ba0 100644
--- a/include/uapi/linux/trace_mmap.h
+
their unique ID, assigned during the
first mapping.
Once mapped, no subbuf can get in or out of the ring-buffer: the buffer
size will remain unmodified and the splice enabling functions will in
reality simply memcpy the data instead of swapping subbufs.
Signed-off-by: Vincent Donnefort
diff
In preparation for the ring-buffer memory mapping where each subbuf will
be accessible to user-space, zero all the page allocations.
Signed-off-by: Vincent Donnefort
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 173d2595ce2d..db73e326fa04 100644
--- a/kernel/trace
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