have malloc/free, alloc_contig/free_contig and mmap/munmap nicely
paired up.
memory uses malloc/free instead of mmap/munmap as it doesn't have
to be contiguous for the ramdisks (and it might help if it doesn't!).
Some cases were fixed by declaring the function void, others were fixed
by adding a return <value> statement, thereby avoiding potentially
incorrect behavior (usually in error handling).
Some enum correctness in boot.c.
Main changes:
- COW optimization for safecopy.
- safemap, a grant-based interface for sharing memory regions between processes.
- Integration with safemap and complete rework of DS, supporting new data types
natively (labels, memory ranges, memory mapped ranges).
- For further information:
http://wiki.minix3.org/en/SummerOfCode2009/MemoryGrants
Additional changes not included in the original Wu's branch:
- Fixed unhandled case in VM when using COW optimization for safecopy in case
of a block that has already been shared as SMAP.
- Better interface and naming scheme for sys_saferevmap and ds_retrieve_map
calls.
- Better input checking in syslib: check for page alignment when creating
memory mapping grants.
- DS notifies subscribers when an entry is deleted.
- Documented the behavior of indirect grants in case of memory mapping.
- Test suite in /usr/src/test/safeperf|safecopy|safemap|ds/* reworked
and extended.
- Minor fixes and general cleanup.
- TO-DO: Grant ids should be generated and managed the way endpoints are to make
sure grant slots are never misreused.
SYSLIB CHANGES:
- SEF framework now supports a new SEF Init request type from RS. 3 different
callbacks are available (init_fresh, init_lu, init_restart) to specify
initialization code when a service starts fresh, starts after a live update,
or restarts.
SYSTEM SERVICE CHANGES:
- Initialization code for system services is now enclosed in a callback SEF will
automatically call at init time. The return code of the callback will
tell RS whether the initialization completed successfully.
- Each init callback can access information passed by RS to initialize. As of
now, each system service has access to the public entries of RS's system process
table to gather all the information required to initialize. This design
eliminates many existing or potential races at boot time and provides a uniform
initialization interface to system services. The same interface will be reused
for the upcoming publish/subscribe model to handle dynamic
registration / deregistration of system services.
VM CHANGES:
- Uniform privilege management for all system services. Every service uses the
same call mask format. For boot services, VM copies the call mask from init
data. For dynamic services, VM still receives the call mask via rs_set_priv
call that will be soon replaced by the upcoming publish/subscribe model.
RS CHANGES:
- The system process table has been reorganized and split into private entries
and public entries. Only the latter ones are exposed to system services.
- VM call masks are now entirely configured in rs/table.c
- RS has now its own slot in the system process table. Only kernel tasks and
user processes not included in the boot image are now left out from the system
process table.
- RS implements the initialization protocol for system services.
- For services in the boot image, RS blocks till initialization is complete and
panics when failure is reported back. Services are initialized in their order of
appearance in the boot image priv table and RS blocks to implements synchronous
initialization for every system service having the flag SF_SYNCH_BOOT set.
- For services started dynamically, the initialization protocol is implemented
as though it were the first ping for the service. In this case, if the
system service fails to report back (or reports failure), RS brings the service
down rather than trying to restart it.
- clean up kernel section of minix/com.h somewhat
- remove ALLOCMEM and VM_ALLOCMEM calls
- remove non-safecopy and minix-vmd support from Inet
- remove SYS_VIRVCOPY and SYS_PHYSVCOPY calls
- remove obsolete segment encoding in SYS_SAFECOPY*
- remove DEVCTL call, svrctl(FSDEVUNMAP), map_driverX
- remove declarations of unimplemented svrctl requests
- remove everything related to swapping to disk
- remove floppysetup.sh
- remove traces of rescue device
- update DESCRIBE.sh with new devices
- some other small changes
RS CHANGES:
- RS retains information on both labels and process names now. Labels for boot
processes are configured in the boot image priv table. Process names are
inherited from the in-kernel boot image table.
- When RS_REUSE is specified in do_up, RS looks for an existing slot having the
same process name as the one we are about to start. If one is found with
an in-memory copy of its executable image, the image is then shared between
the two processes, rather than copying it again. This behavior can be specified
by using 'service -r' when starting a system service from the command line.
- if "debug_fkeys" boot monitor variable is set to 0:
- pass Fn, Shift+Fn, Ctrl+Fn, Shift+Ctrl+Fn to applications
- don't start IS
- update termcap files with function key, color, end key support
- optionally vectorize I/O requests to work around hardware bugs
- extend default buffer size to cover MFS's default maximum request size
- use mmap directly, rather than alloc_contig
- add 'nil' checksum type for comparison with layout
- minor style corrections
SYSLIB CHANGES:
- SEF must be used by every system process and is thereby part of the system
library.
- The framework provides a receive() interface (sef_receive) for system
processes to automatically catch known system even messages and process them.
- SEF provides a default behavior for each type of system event, but allows
system processes to register callbacks to override the default behavior.
- Custom (local to the process) or predefined (provided by SEF) callback
implementations can be registered to SEF.
- SEF currently includes support for 2 types of system events:
1. SEF Ping. The event occurs every time RS sends a ping to figure out
whether a system process is still alive. The default callback implementation
provided by SEF is to notify RS back to let it know the process is alive
and kicking.
2. SEF Live update. The event occurs every time RS sends a prepare to update
message to let a system process know an update is available and to prepare
for it. The live update support is very basic for now. SEF only deals with
verifying if the prepare state can be supported by the process, dumping the
state for debugging purposes, and providing an event-driven programming
model to the process to react to state changes check-in when ready to update.
- SEF should be extended in the future to integrate support for more types of
system events. Ideally, all the cross-cutting concerns should be integrated into
SEF to avoid duplicating code and ease extensibility. Examples include:
* PM notify messages primarily used at shutdown.
* SYSTEM notify messages primarily used for signals.
* CLOCK notify messages used for system alarms.
* Debug messages. IS could still be in charge of fkey handling but would
forward the debug message to the target process (e.g. PM, if the user
requested debug information about PM). SEF would then catch the message and
do nothing unless the process has registered an appropriate callback to
deal with the event. This simplifies the programming model to print debug
information, avoids duplicating code, and reduces the effort to print
debug information.
SYSTEM PROCESSES CHANGES:
- Every system process registers SEF callbacks it needs to override the default
system behavior and calls sef_startup() right after being started.
- sef_startup() does almost nothing now, but will be extended in the future to
support callbacks of its own to let RS control and synchronize with every
system process at initialization time.
- Every system process calls sef_receive() now rather than receive() directly,
to let SEF handle predefined system events.
RS CHANGES:
- RS supports a basic single-component live update protocol now, as follows:
* When an update command is issued (via "service update *"), RS notifies the
target system process to prepare for a specific update state.
* If the process doesn't respond back in time, the update is aborted.
* When the process responds back, RS kills it and marks it for refreshing.
* The process is then automatically restarted as for a buggy process and can
start running again.
* Live update is currently prototyped as a controlled failure.
/etc CHANGES:
- /etc/drivers.conf has been renamed to /etc/system.conf. Every entry in
the file is now marked as "service" rather than driver.
- user "service" has been added to password file /etc/passwd.
- docs/UPDATING updated accordingly, as well as every other mention to the old
drivers.conf in the system.
RS CHANGES:
- No more distinction between servers and drivers.
- RS_START has been renamed to RS_UP and the old legacy RS_UP and RS_UP_COPY
dropped.
- RS asks PCI to set / remove ACL entries only for services whose ACL properties
have been set. This change eliminates unnecessary warnings.
- Temporarily minimize the risk of potential races at boot time or when starting
a new service. Upcoming changes will eliminate races completely.
- General cleanup.
