aboutsummaryrefslogtreecommitdiffstats
path: root/erts/emulator
diff options
context:
space:
mode:
authorLukas Larsson <[email protected]>2018-07-07 11:33:54 +0200
committerBjörn Gustavsson <[email protected]>2019-04-04 12:30:20 +0200
commitfa9e189d90a35f2ce4b7fc145c994828f34b3548 (patch)
tree8031ef661e551a2e4e557f3401b6a857293e7fa9 /erts/emulator
parent0a8bb0bc0a33ddd100278f35460cdfaffa7c15ae (diff)
downloadotp-fa9e189d90a35f2ce4b7fc145c994828f34b3548.tar.gz
otp-fa9e189d90a35f2ce4b7fc145c994828f34b3548.tar.bz2
otp-fa9e189d90a35f2ce4b7fc145c994828f34b3548.zip
erl_docgen: Add new internal docs chapter to docs
Diffstat (limited to 'erts/emulator')
-rw-r--r--erts/emulator/internal_doc/CarrierMigration.md27
-rw-r--r--erts/emulator/internal_doc/CodeLoading.md6
-rw-r--r--erts/emulator/internal_doc/PTables.md4
-rw-r--r--erts/emulator/internal_doc/SuperCarrier.md10
-rw-r--r--erts/emulator/internal_doc/Tracing.md4
5 files changed, 27 insertions, 24 deletions
diff --git a/erts/emulator/internal_doc/CarrierMigration.md b/erts/emulator/internal_doc/CarrierMigration.md
index bb3d8aac28..40f6031ca8 100644
--- a/erts/emulator/internal_doc/CarrierMigration.md
+++ b/erts/emulator/internal_doc/CarrierMigration.md
@@ -1,6 +1,9 @@
Carrier Migration
=================
+Introduction
+------------
+
The ERTS memory allocators manage memory blocks in two types of raw
memory chunks. We call these chunks of raw memory
*carriers*. Single-block carriers which only contain one large block,
@@ -141,11 +144,11 @@ Since the carrier has been unlinked from the data structure of
available free blocks, no more allocations will be made in the
carrier.
-The allocator instance that created a carrier is called its **owner**.
+The allocator instance that created a carrier is called its *owner*.
Ownership never changes.
The allocator instance that has the responsibility to perform deallocations in a
-carrier is called its **employer**. The employer may also perform allocations if
+carrier is called its *employer*. The employer may also perform allocations if
the carrier is not in the pool. Employment may change when a carrier is fetched from
or inserted into the pool.
@@ -153,14 +156,14 @@ Deallocations in a carrier, while it remains in the pool, is always performed
the owner. That is, all pooled carriers are employed by their owners.
Each carrier has an atomic word containing a pointer to the employing allocator
-instance and three bit flags; IN_POOL, BUSY and HOMECOMING.
+instance and three bit flags; IN\_POOL, BUSY and HOMECOMING.
When fetching a carrier from the pool, employment may change and further
deallocations in the carrier will be redirected to the new
employer using the delayed dealloc functionality.
When a foreign allocator instance abandons a carrier back into the pool, it will
-also pass it back to its **owner** using the delayed dealloc queue. When doing
+also pass it back to its *owner* using the delayed dealloc queue. When doing
this it will set the HOMECOMING bit flag to mark it as "enqueued". The owner
will later clear the HOMECOMING bit when the carrier is dequeued. This mechanism
prevents a carrier from being enqueued again before it has been dequeued.
@@ -180,14 +183,14 @@ back to the owner for deallocation using the delayed dealloc functionality.
In short:
-* The allocator instance that created a carrier **owns** it.
-* An empty carrier is always deallocated by its **owner**.
-* **Ownership** never changes.
-* The allocator instance that uses a carrier **employs** it.
-* An **employer** can abandon a carrier into the pool.
+* The allocator instance that created a carrier *owns* it.
+* An empty carrier is always deallocated by its *owner*.
+* *Ownership* never changes.
+* The allocator instance that uses a carrier *employs* it.
+* An *employer* can abandon a carrier into the pool.
* Pooled carriers are not allocated from.
-* Pooled carriers are always **employed** by their **owner**.
-* **Employment** can only change from **owner** to a foreign allocator
+* Pooled carriers are always *employed* by their *owner*.
+* *Employment* can only change from *owner* to a foreign allocator
when a carrier is fetched from the pool.
@@ -229,7 +232,7 @@ carrier. When the cluster gets to the same size as the search limit,
all searches will essentially fail.
To counter the "bad cluster" problem and also ease the contention, the
-search will now always start by first looking at the allocators **own**
+search will now always start by first looking at the allocators *own*
carriers. That is, carriers that were initially created by the
allocator itself and later had been abandoned to the pool. If none of
our own abandoned carrier would do, then the search continues into the
diff --git a/erts/emulator/internal_doc/CodeLoading.md b/erts/emulator/internal_doc/CodeLoading.md
index 151b9cd57c..0b2e3070e7 100644
--- a/erts/emulator/internal_doc/CodeLoading.md
+++ b/erts/emulator/internal_doc/CodeLoading.md
@@ -45,7 +45,7 @@ free to schedule other work while the second loader is waiting. (See
`erts_release_code_write_permission`).
The ability to prepare several modules in parallel is not currently
-used as almost all code loading is serialized by the code_server
+used as almost all code loading is serialized by the code\_server
process. The BIF interface is however prepared for this.
erlang:prepare_loading(Module, Code) -> LoaderState
@@ -71,8 +71,8 @@ structures. These *code access structures* are
* Export table. One entry for every exported function.
* Module table. One entry for each loaded module.
-* "beam_catches". Identifies jump destinations for catch instructions.
-* "beam_ranges". Map code address to function and line in source file.
+* "beam\_catches". Identifies jump destinations for catch instructions.
+* "beam\_ranges". Map code address to function and line in source file.
The most frequently used of these structures is the export table that
is accessed in run time for every executed external function call to
diff --git a/erts/emulator/internal_doc/PTables.md b/erts/emulator/internal_doc/PTables.md
index 6fe0e7665d..ef61963a40 100644
--- a/erts/emulator/internal_doc/PTables.md
+++ b/erts/emulator/internal_doc/PTables.md
@@ -85,13 +85,13 @@ following:
3. Depending on use, issue appropriate memory barrier.
A common barrier used is a barrier with acquire semantics. On
- x86/x86_64 this maps to a compiler barrier preventing the compiler
+ x86/x86\_64 this maps to a compiler barrier preventing the compiler
to reorder instructions, but on other hardware often some kind of
light weight hardware memory barrier is also needed.
When comparing with a locked approach, at least one heavy weight
memory barrier will be issued when locking the lock on most, if
- not all, hardware architectures (including x86/x86_64), and often
+ not all, hardware architectures (including x86/x86\_64), and often
some kind of light weight memory barrier will be issued when
unlocking the lock.
diff --git a/erts/emulator/internal_doc/SuperCarrier.md b/erts/emulator/internal_doc/SuperCarrier.md
index acf722ea37..f52c6613d5 100644
--- a/erts/emulator/internal_doc/SuperCarrier.md
+++ b/erts/emulator/internal_doc/SuperCarrier.md
@@ -5,7 +5,7 @@ A super carrier is large memory area, allocated at VM start, which can
be used during runtime to allocate normal carriers from.
The super carrier feature was introduced in OTP R16B03. It is
-enabled with command line option +MMscs <size in Mb>
+enabled with command line option +MMscs &lt;size in Mb&gt;
and can be configured with other options.
Problem
@@ -65,7 +65,7 @@ carrier is full.
### Implementation ###
-The entire super carrier implementation is kept in erl_mmap.c. The
+The entire super carrier implementation is kept in erl\_mmap.c. The
name suggest that it can be viewed as our own mmap implementation.
A super carrier needs to satisfy two slightly different kinds of
@@ -98,8 +98,8 @@ other.
### Data structures ###
-The MBC area is called **sa** as in super aligned and the SBC area is
-called **sua** as in super un-aligned.
+The MBC area is called *sa* as in super aligned and the SBC area is
+called *sua* as in super un-aligned.
Note that the "super" in super alignment and the "super" in super
carrier has nothing to do with each other. We could have choosen
@@ -128,7 +128,7 @@ down or up.
We need to keep track of all the free segments in order to reuse them
for new carrier allocations. One initial idea was to use the same
mechanism that is used to keep track of free blocks within MBCs
-(alloc_util and the different strategies). However, that would not be
+(alloc\_util and the different strategies). However, that would not be
as straight forward as one can think and can also waste quite a lot of
memory as it uses prepended block headers. The granularity of the
super carrier is one memory page (usually 4kb). We want to allocate
diff --git a/erts/emulator/internal_doc/Tracing.md b/erts/emulator/internal_doc/Tracing.md
index 7f97f64765..1b3b0fe1b8 100644
--- a/erts/emulator/internal_doc/Tracing.md
+++ b/erts/emulator/internal_doc/Tracing.md
@@ -82,7 +82,7 @@ through when adding a new breakpoint.
instruction word in the breakpoint.
3. Write a pointer to the breakpoint at offset -4 from the first
- instruction "func_info" header.
+ instruction "func\_info" header.
4. Set the staging part of the breakpoint as enabled with specified
breakpoint data.
@@ -139,7 +139,7 @@ and removing breakpoints.
2. Allocate new breakpoint structures with a disabled active part and
the original beam instruction. Write a pointer to the breakpoint in
- "func_info" header at offset -4.
+ "func\_info" header at offset -4.
3. Update the staging part of all affected breakpoints. Disable
breakpoints that are to be removed.