[PATCH/RFCv4 0/6] The Contiguous Memory Allocator framework

Michal Nazarewicz
2010-08-20T09:50:40Z

Hello everyone,

The following patchset implements a Contiguous Memory Allocator. For
those who have not yet stumbled across CMA an excerpt from
documentation:

The Contiguous Memory Allocator (CMA) is a framework, which allows
setting up a machine-specific configuration for physically-contiguous
memory management. Memory for devices is then allocated according
to that configuration.

The main role of the framework is not to allocate memory, but to
parse and manage memory configurations, as well as to act as an
in-between between device drivers and pluggable allocators. It is
thus not tied to any memory allocation method or strategy.

For more information please refer to the second patch from the
patchset which contains the documentation.

Links to the previous versions of the patchsets:
v3: <http://article.gmane.org/gmane.linux.kernel.mm/51573/>
v2: <http://article.gmane.org/gmane.linux.kernel.mm/50986/>
v1: <http://article.gmane.org/gmane.linux.kernel.mm/50669/>

v4: 1. The "asterisk" flag has been removed in favour of requiring
that platform will provide a "*=<regions>" rule in the map
attribute.

2. The terminology has been changed slightly renaming "kind" to
"type" of memory. In the previous revisions, the documentation
indicated that device drivers define memory kinds and now,

v3: 1. The command line parameters have been removed (and moved to
a separate patch, the fourth one). As a consequence, the
cma_set_defaults() function has been changed -- it no longer
accepts a string with list of regions but an array of regions.

2. The "asterisk" attribute has been removed. Now, each region
has an "asterisk" flag which lets one specify whether this
region should by considered "asterisk" region.

3. SysFS support has been moved to a separate patch (the third one
in the series) and now also includes list of regions.

v2: 1. The "cma_map" command line have been removed. In exchange,
a SysFS entry has been created under kernel/mm/contiguous.

The intended way of specifying the attributes is
a cma_set_defaults() function called by platform initialisation
code. "regions" attribute (the string specified by "cma"
command line parameter) can be overwritten with command line
parameter; the other attributes can be changed during run-time
using the SysFS entries.

2. The behaviour of the "map" attribute has been modified
slightly. Currently, if no rule matches given device it is
assigned regions specified by the "asterisk" attribute. It is
by default built from the region names given in "regions"
attribute.

3. Devices can register private regions as well as regions that
can be shared but are not reserved using standard CMA
mechanisms. A private region has no name and can be accessed
only by devices that have the pointer to it.

4. The way allocators are registered has changed. Currently,
a cma_allocator_register() function is used for that purpose.
Moreover, allocators are attached to regions the first time
memory is registered from the region or when allocator is
registered which means that allocators can be dynamic modules
that are loaded after the kernel booted (of course, it won't be
possible to allocate a chunk of memory from a region if
allocator is not loaded).

5. Index of new functions:

+static inline dma_addr_t __must_check
+cma_alloc_from(const char *regions, size_t size,
+ dma_addr_t alignment)

+static inline int
+cma_info_about(struct cma_info *info, const const char *regions)

+int __must_check cma_region_register(struct cma_region *reg);

+dma_addr_t __must_check
+cma_alloc_from_region(struct cma_region *reg,
+ size_t size, dma_addr_t alignment);

+static inline dma_addr_t __must_check
+cma_alloc_from(const char *regions,
+ size_t size, dma_addr_t alignment);

+int cma_allocator_register(struct cma_allocator *alloc);

Michal Nazarewicz (6):
lib: rbtree: rb_root_init() function added
mm: cma: Contiguous Memory Allocator added
mm: cma: Added SysFS support
mm: cma: Added command line parameters support
mm: cma: Test device and application added
arm: Added CMA to Aquila and Goni

Documentation/00-INDEX | 2 +
.../ABI/testing/sysfs-kernel-mm-contiguous | 53 +
Documentation/contiguous-memory.txt | 620 +++++++++
Documentation/kernel-parameters.txt | 7 +
arch/arm/mach-s5pv210/mach-aquila.c | 31 +
arch/arm/mach-s5pv210/mach-goni.c | 31 +
drivers/misc/Kconfig | 8 +
drivers/misc/Makefile | 1 +
drivers/misc/cma-dev.c | 185 +++
include/linux/cma.h | 468 +++++++
include/linux/rbtree.h | 11 +
mm/Kconfig | 54 +
mm/Makefile | 2 +
mm/cma-best-fit.c | 407 ++++++
mm/cma.c | 1376 ++++++++++++++++++++
tools/cma/cma-test.c | 373 ++++++
16 files changed, 3629 insertions(+), 0 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-kernel-mm-contiguous
create mode 100644 Documentation/contiguous-memory.txt
create mode 100644 drivers/misc/cma-dev.c
create mode 100644 include/linux/cma.h
create mode 100644 mm/cma-best-fit.c
create mode 100644 mm/cma.c
create mode 100644 tools/cma/cma-test.c