It's been a long time since anyone has looked at what struct tty_struct
looks like in memory, turns out there was a ton of holes.
So move things around a bit, change one variable (closing) from being an
int to a bool (it is only being tested for 0/1), and we end up saving 40
bytes per structure overall on x86-64 systems.
Before this patch:
/* size: 696, cachelines: 11, members: 37 */
/* sum members: 665, holes: 8, sum holes: 31 */
/* forced alignments: 2, forced holes: 1, sum forced holes: 4 */
/* last cacheline: 56 bytes */
After this change:
/* size: 656, cachelines: 11, members: 37 */
/* sum members: 654, holes: 1, sum holes: 2 */
/* forced alignments: 2 */
/* last cacheline: 16 bytes */
Cc: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/2023082519-cobbler-unholy-8d1f@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull driver core updates from Greg KH:
"Here is the large set of driver core changes for 6.4-rc1.
Once again, a busy development cycle, with lots of changes happening
in the driver core in the quest to be able to move "struct bus" and
"struct class" into read-only memory, a task now complete with these
changes.
This will make the future rust interactions with the driver core more
"provably correct" as well as providing more obvious lifetime rules
for all busses and classes in the kernel.
The changes required for this did touch many individual classes and
busses as many callbacks were changed to take const * parameters
instead. All of these changes have been submitted to the various
subsystem maintainers, giving them plenty of time to review, and most
of them actually did so.
Other than those changes, included in here are a small set of other
things:
- kobject logging improvements
- cacheinfo improvements and updates
- obligatory fw_devlink updates and fixes
- documentation updates
- device property cleanups and const * changes
- firwmare loader dependency fixes.
All of these have been in linux-next for a while with no reported
problems"
* tag 'driver-core-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (120 commits)
device property: make device_property functions take const device *
driver core: update comments in device_rename()
driver core: Don't require dynamic_debug for initcall_debug probe timing
firmware_loader: rework crypto dependencies
firmware_loader: Strip off \n from customized path
zram: fix up permission for the hot_add sysfs file
cacheinfo: Add use_arch[|_cache]_info field/function
arch_topology: Remove early cacheinfo error message if -ENOENT
cacheinfo: Check cache properties are present in DT
cacheinfo: Check sib_leaf in cache_leaves_are_shared()
cacheinfo: Allow early level detection when DT/ACPI info is missing/broken
cacheinfo: Add arm64 early level initializer implementation
cacheinfo: Add arch specific early level initializer
tty: make tty_class a static const structure
driver core: class: remove struct class_interface * from callbacks
driver core: class: mark the struct class in struct class_interface constant
driver core: class: make class_register() take a const *
driver core: class: mark class_release() as taking a const *
driver core: remove incorrect comment for device_create*
MIPS: vpe-cmp: remove module owner pointer from struct class usage.
...
Move the partial tty_struct::flags documentation from tty_ldisc to the
tty.h header and combine it with the one-liners present there. Convert
all those to kernel-doc. This way, we can simply reference the
documentation in Documentation while the text is still along the
definitions.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-10-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There are already pieces of kernel-doc documentation for struct
tty_struct in tty.h. Finish the documentation for the members which were
undocumented yet.
It also includes tuning the already existing pieces like flow and ctrl,
especially adding highlights to them.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty.h is long enough already. And I am slowly adding kernel-doc
documentation, so it grows to unmaintainable long mess. To avoid this,
split tty.h further into tty_port.h and move there tty_port-related
declarations and function prototypes (those implemented in tty_port.c).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723103147.18250-8-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty.h is large enough currently. And I am slowly adding kernel-doc
documentation, so it grows to unmaintainable long mess. To avoid this,
split tty.h further into tty_buffer.h and move there tty_buffer-related
declarations and function prototypes.
Note that many of the tty_buffer.c function prototypes reside now in
tty_flip.h. But we cannot move struct tty_buffer & friends because:
* tty_insert_flip_char() in tty_flip.h needs both struct tty_port and
struct tty_buffer defined.
* struct tty_port in tty_port.h needs struct tty_buffer defined.
So if we moved struct tty_buffer to tty_flip.h too, tty_flip.h would
need tty_port.h and that would need tty_flip.h (to have tty_buffer)
again. Hence we introduce new header tty_buffer.h here to break this
circular dependency.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723103147.18250-7-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Many tty drivers contain code to compute bits count depending on termios
cflags. So extract this code from serial core to two separate tty helper
functions:
* tty_get_char_size -- only size of a character, without flags,
* tty_get_frame_size -- complete size of a frame including flags.
In the next patch, calls to these new functions replace many copies of
this code.
Note that we accept only cflag as a parameter. That's because some
callers like pch_uart_startup or sunsab_console_setup don't have at hand
termios which we could pass around.
Cc: Joe Perches <joe@perches.com>
Cc: Johan Hovold <johan@kernel.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210610090247.2593-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
