Commit Graph

1106901 Commits

Author SHA1 Message Date
Willy Tarreau
99b037cbd5 tools/nolibc/stdio: add stdin/stdout/stderr and fget*/fput* functions
The standard puts() function always emits the trailing LF which makes it
unconvenient for small string concatenation. fputs() ought to be used
instead but it requires a FILE*.

This adds 3 dummy FILE* values (stdin, stdout, stderr) which are in fact
pointers to struct FILE of one byte. We reserve 3 pointer values for them,
-3, -2 and -1, so that they are ordered, easing the tests and mapping to
integer.

>From this, fgetc(), fputc(), fgets() and fputs() were implemented, and
the previous putchar() and getchar() now remap to these. The standard
getc() and putc() macros were also implemented as pointing to these
ones.

There is absolutely no buffering, fgetc() and fgets() read one byte at
a time, fputc() writes one byte at a time, and only fputs() which knows
the string's length writes all of it at once.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:44 -07:00
Willy Tarreau
4e383a66ac tools/nolibc/stdio: add a minimal set of stdio functions
This only provides getchar(), putchar(), and puts().

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:44 -07:00
Willy Tarreau
5f493178ef tools/nolibc/stdlib: add utoh() and u64toh()
This adds a pair of functions to emit hex values.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:44 -07:00
Willy Tarreau
b1c21e7d99 tools/nolibc/stdlib: add i64toa() and u64toa()
These are 64-bit variants of the itoa() and utoa() functions. They also
support reentrant ones, and use the same itoa_buffer. The functions are
a bit larger than the previous ones in 32-bit mode (86 and 98 bytes on
x86_64 and armv7 respectively), which is why we continue to provide them
as separate functions.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:44 -07:00
Willy Tarreau
66c397c4d2 tools/nolibc/stdlib: replace the ltoa() function with more efficient ones
The original ltoa() function and the reentrant one ltoa_r() present a
number of drawbacks. The divide by 10 generates calls to external code
from libgcc_s, and the number does not necessarily start at the beginning
of the buffer.

Let's rewrite these functions so that they do not involve a divide and
only use loops on powers of 10, and implement both signed and unsigned
variants, always starting from the buffer's first character. Instead of
using a static buffer for each function, we're now using a common one.

In order to avoid confusion with the ltoa() name, the new functions are
called itoa_r() and utoa_r() to distinguish the signed and unsigned
versions, and for convenience for their callers, these functions now
reutrn the number of characters emitted. The ltoa_r() function is just
an inline mapping to the signed one and which returns the buffer.

The functions are quite small (86 bytes on x86_64, 68 on armv7) and
do not depend anymore on external code.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:43 -07:00
Willy Tarreau
56d68a3c1f tools/nolibc/stdlib: move ltoa() to stdlib.h
This function is not standard and performs the opposite of atol(). Let's
move it with atol(). It's been split between a reentrant function and one
using a static buffer.

There's no more definition in nolibc.h anymore now.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:43 -07:00
Willy Tarreau
eba6d00d38 tools/nolibc/types: move makedev to types.h and make it a macro
The makedev() man page says it's supposed to be a macro and that some
OSes have it with the other ones in sys/types.h so it now makes sense
to move it to types.h as a macro. Let's also define major() and
minor() that perform the reverse operation.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:43 -07:00
Willy Tarreau
306c9fd4c6 tools/nolibc/types: make FD_SETSIZE configurable
The macro was hard-coded to 256 but it's common to see it redefined.
Let's support this and make sure we always allocate enough entries for
the cases where it wouldn't be multiple of 32.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:43 -07:00
Willy Tarreau
8cb98b3fce tools/nolibc/types: move the FD_* functions to macros in types.h
FD_SET, FD_CLR, FD_ISSET, FD_ZERO are often expected to be macros and
not functions. In addition we already have a file dedicated to such
macros and types used by syscalls, it's types.h, so let's move them
there and turn them to macros. FD_CLR() and FD_ISSET() were missing,
so they were added. FD_ZERO() now deals with its own loop so that it
doesn't rely on memset() that sets one byte at a time.

Cc: David Laight <David.Laight@aculab.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:43 -07:00
Willy Tarreau
50850c38b2 tools/nolibc/ctype: add the missing is* functions
There was only isdigit, this commit adds the other ones.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:43 -07:00
Willy Tarreau
62a2af0774 tools/nolibc/ctype: split the is* functions to ctype.h
In fact there's only isdigit() for now. More should definitely be added.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:43 -07:00
Willy Tarreau
c91eb03389 tools/nolibc/string: split the string functions into string.h
The string manipulation functions (mem*, str*) are now found in
string.h. The file depends on almost nothing and will be
usable from other includes if needed. Maybe more functions could
be added.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:43 -07:00
Willy Tarreau
06fdba53e0 tools/nolibc/stdlib: extract the stdlib-specific functions to their own file
The new file stdlib.h contains the definitions of functions that
are usually found in stdlib.h. Many more could certainly be added.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:43 -07:00
Willy Tarreau
bd8c8fbb86 tools/nolibc/sys: split the syscall definitions into their own file
The syscall definitions were moved to sys.h. They were arranged
in a more easily maintainable order, whereby the sys_xxx() and xxx()
functions were grouped together, which also enlights the occasional
mappings such as wait relying on wait4().

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:43 -07:00
Willy Tarreau
271661c1cd tools/nolibc/arch: split arch-specific code into individual files
In order to ease maintenance, this splits the arch-specific code into
one file per architecture. A common file "arch.h" is used to include the
right file among arch-* based on the detected architecture. Projects
which are already split per architecture could simply rename these
files to $arch/arch.h and get rid of the common arch.h. For this
reason, include guards were placed into each arch-specific file.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:43 -07:00
Willy Tarreau
cc7a492ad0 tools/nolibc/types: split syscall-specific definitions into their own files
The macros and type definitions used by a number of syscalls were moved
to types.h where they will be easier to maintain. A few of them
are arch-specific and must not be moved there (e.g. O_*, sys_stat_struct).
A warning about them was placed at the top of the file.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:43 -07:00
Willy Tarreau
967cce191f tools/nolibc/std: move the standard type definitions to std.h
The ordering of includes and definitions for now is a bit of a mess, as
for example asm/signal.h is included after int definitions, but plenty of
structures are defined later as they rely on other includes.

Let's move the standard type definitions to a dedicated file that is
included first. We also move NULL there. This way all other includes
are aware of it, and we can bring asm/signal.h back to the top of the
file.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 17:05:33 -07:00
Paul E. McKenney
fb036ad7db rcutorture: Make torture.sh allow for --kasan
The torture.sh script provides extra memory for scftorture and rcuscale.
However, the total memory provided is only 1G, which is less than the
2G that is required for KASAN testing.  This commit therefore ups the
torture.sh script's 1G to 2G.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:55:03 -07:00
Paul E. McKenney
d69e048b27 rcutorture: Make torture.sh refscale and rcuscale specify Tasks Trace RCU
Now that the Tasks RCU flavors are selected by their users rather than
by the rcutorture scenarios, torture.sh fails when attempting to run
NOPREEMPT scenarios for refscale and rcuscale.  This commit therefore
makes torture.sh specify CONFIG_TASKS_TRACE_RCU=y to avoid such failure.

Why not also CONFIG_TASKS_RCU?  Because tracing selects this one.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:55:03 -07:00
Paul E. McKenney
3101562576 rcutorture: Make kvm.sh allow more memory for --kasan runs
KASAN allots significant memory to track allocation state, and the amount
of memory has increased recently, which results in frequent OOMs on a
few of the rcutorture scenarios.  This commit therefore provides 2G of
memory for --kasan runs, up from the 512M default.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:55:03 -07:00
Paul E. McKenney
c7756fff4f torture: Save "make allmodconfig" .config file
Currently, torture.sh saves only the build output and exit code from the
"make allmodconfig" test.  This commit also saves the .config file.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:55:03 -07:00
Paul E. McKenney
f877e3993b scftorture: Remove extraneous "scf" from per_version_boot_params
There is an extraneous "scf" in the per_version_boot_params shell function
used by scftorture.  No harm done in that it is just passed as an argument
to the /init program in initrd, but this commit nevertheless removes it.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:55:03 -07:00
Paul E. McKenney
eec52c7fb5 rcutorture: Adjust scenarios' Kconfig options for CONFIG_PREEMPT_DYNAMIC
Now that CONFIG_PREEMPT_DYNAMIC=y is the default, kernels that are
ostensibly built with CONFIG_PREEMPT_NONE=y or CONFIG_PREEMPT_VOLUNTARY=y
are now actually built with CONFIG_PREEMPT=y, but are by default booted
so as to disable preemption.  Although this allows much more flexibility
from a single kernel binary, it means that the current rcutorture
scenarios won't find build errors that happen only when preemption is
fully disabled at build time.

This commit therefore adds CONFIG_PREEMPT_DYNAMIC=n to several scenarios,
and while in the area switches one from CONFIG_PREEMPT_NONE=y to
CONFIG_PREEMPT_VOLUNTARY=y to add coverage of this Kconfig option.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:55:03 -07:00
Paul E. McKenney
3e112a39f7 torture: Enable CSD-lock stall reports for scftorture
This commit passes the csdlock_debug=1 kernel parameter in order to
enable CSD-lock stall reports for torture.sh scftorure runs.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:55:03 -07:00
Paul E. McKenney
00f3133b7f torture: Skip vmlinux check for kvm-again.sh runs
The kvm-again.sh script reruns an previously built set of kernels, so
the vmlinux files are associated with that previous run, not this on.
This results in kvm-find_errors.sh reporting spurious failed-build errors.
This commit therefore omits the vmlinux check for kvm-again.sh runs.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:54:56 -07:00
Paul E. McKenney
bf5e7a2f46 scftorture: Adjust for TASKS_RCU Kconfig option being selected
This commit adjusts the scftorture PREEMPT and NOPREEMPT scenarios to
account for the TASKS_RCU Kconfig option being explicitly selected rather
than computed in isolation.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:53:19 -07:00
Paul E. McKenney
5ce027f4cd rcuscale: Allow rcuscale without RCU Tasks Rude/Trace
Currently, a CONFIG_PREEMPT_NONE=y kernel substitutes normal RCU for
RCU Tasks Rude and RCU Tasks Trace.  Unless that kernel builds rcuscale,
whether built-in or as a module, in which case these RCU Tasks flavors are
(unnecessarily) built in.  This both increases kernel size and increases
the complexity of certain tracing operations.  This commit therefore
decouples the presence of rcuscale from the presence of RCU Tasks Rude
and RCU Tasks Trace.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:53:19 -07:00
Paul E. McKenney
4df002d908 rcuscale: Allow rcuscale without RCU Tasks
Currently, a CONFIG_PREEMPT_NONE=y kernel substitutes normal RCU for
RCU Tasks.  Unless that kernel builds rcuscale, whether built-in or as
a module, in which case RCU Tasks is (unnecessarily) built.  This both
increases kernel size and increases the complexity of certain tracing
operations.  This commit therefore decouples the presence of rcuscale
from the presence of RCU Tasks.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:53:19 -07:00
Paul E. McKenney
dec86781a5 refscale: Allow refscale without RCU Tasks Rude/Trace
Currently, a CONFIG_PREEMPT_NONE=y kernel substitutes normal RCU for
RCU Tasks Rude and RCU Tasks Trace.  Unless that kernel builds refscale,
whether built-in or as a module, in which case these RCU Tasks flavors are
(unnecessarily) built in.  This both increases kernel size and increases
the complexity of certain tracing operations.  This commit therefore
decouples the presence of refscale from the presence of RCU Tasks Rude
and RCU Tasks Trace.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:53:19 -07:00
Paul E. McKenney
5f654af150 refscale: Allow refscale without RCU Tasks
Currently, a CONFIG_PREEMPT_NONE=y kernel substitutes normal RCU for
RCU Tasks.  Unless that kernel builds refscale, whether built-in or as a
module, in which case RCU Tasks is (unnecessarily) built in.  This both
increases kernel size and increases the complexity of certain tracing
operations.  This commit therefore decouples the presence of refscale
from the presence of RCU Tasks.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:53:19 -07:00
Paul E. McKenney
58524e0fed rcutorture: Allow specifying per-scenario stat_interval
The rcutorture test suite makes double use of the rcutorture.stat_interval
module parameter.  As its name suggests, it controls the frequency
of statistics printing, but it also controls the rcu_torture_writer()
stall timeout.  The current setting of 15 seconds works surprisingly well.
However, given that the RCU tasks stall-warning timeout is ten -minutes-,
15 seconds is too short for TASKS02, which runs a non-preemptible kernel
on a single CPU.

This commit therefore adds checks for per-scenario specification of the
rcutorture.stat_interval module parameter.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:53:19 -07:00
Paul E. McKenney
3831fc02f4 rcutorture: Add CONFIG_PREEMPT_DYNAMIC=n to TASKS02 scenario
Now that CONFIG_PREEMPT_DYNAMIC=y is the default, TASKS02 no longer
builds a pure non-preemptible kernel that uses Tiny RCU.  This commit
therefore fixes this new hole in rcutorture testing by adding
CONFIG_PREEMPT_DYNAMIC=n to the TASKS02 rcutorture scenario.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:53:19 -07:00
Paul E. McKenney
4c3f7b0e1e rcutorture: Allow rcutorture without RCU Tasks Rude
Unless a kernel builds rcutorture, whether built-in or as a module, that
kernel is also built with CONFIG_TASKS_RUDE_RCU, whether anything else
needs Tasks Rude RCU or not.  This unnecessarily increases kernel size.
This commit therefore decouples the presence of rcutorture from the
presence of RCU Tasks Rude.

However, there is a need to select CONFIG_TASKS_RUDE_RCU for testing
purposes.  Except that casual users must not be bothered with
questions -- for them, this needs to be fully automated.  There is
thus a CONFIG_FORCE_TASKS_RUDE_RCU that selects CONFIG_TASKS_RUDE_RCU,
is user-selectable, but which depends on CONFIG_RCU_EXPERT.

[ paulmck: Apply kernel test robot feedback. ]

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:53:19 -07:00
Paul E. McKenney
3b6e1dd423 rcutorture: Allow rcutorture without RCU Tasks
Currently, a CONFIG_PREEMPT_NONE=y kernel substitutes normal RCU for
RCU Tasks.  Unless that kernel builds rcutorture, whether built-in or as
a module, in which case RCU Tasks is (unnecessarily) used.  This both
increases kernel size and increases the complexity of certain tracing
operations.  This commit therefore decouples the presence of rcutorture
from the presence of RCU Tasks.

However, there is a need to select CONFIG_TASKS_RCU for testing purposes.
Except that casual users must not be bothered with questions -- for them,
this needs to be fully automated.  There is thus a CONFIG_FORCE_TASKS_RCU
that selects CONFIG_TASKS_RCU, is user-selectable, but which depends
on CONFIG_RCU_EXPERT.

[ paulmck: Apply kernel test robot feedback. ]

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:53:19 -07:00
Paul E. McKenney
40c1278aa7 rcutorture: Allow rcutorture without RCU Tasks Trace
Unless a kernel builds rcutorture, whether built-in or as a module, that
kernel is also built with CONFIG_TASKS_TRACE_RCU, whether anything else
needs Tasks Trace RCU or not.  This unnecessarily increases kernel size.
This commit therefore decouples the presence of rcutorture from the
presence of RCU Tasks Trace.

However, there is a need to select CONFIG_TASKS_TRACE_RCU for
testing purposes.  Except that casual users must not be bothered with
questions -- for them, this needs to be fully automated.  There is thus
a CONFIG_FORCE_TASKS_TRACE_RCU that selects CONFIG_TASKS_TRACE_RCU,
is user-selectable, but which depends on CONFIG_RCU_EXPERT.

[ paulmck: Apply kernel test robot feedback. ]

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:53:19 -07:00
Paul E. McKenney
835f14ed53 rcu: Make the TASKS_RCU Kconfig option be selected
Currently, any kernel built with CONFIG_PREEMPTION=y also gets
CONFIG_TASKS_RCU=y, which is not helpful to people trying to build
preemptible kernels of minimal size.

Because CONFIG_TASKS_RCU=y is needed only in kernels doing tracing of
one form or another, this commit moves from TASKS_RCU deciding when it
should be enabled to the tracing Kconfig options explicitly selecting it.
This allows building preemptible kernels without TASKS_RCU, if desired.

This commit also updates the SRCU-N and TREE09 rcutorture scenarios
in order to avoid Kconfig errors that would otherwise result from
CONFIG_TASKS_RCU being selected without its CONFIG_RCU_EXPERT dependency
being met.

[ paulmck: Apply BPF_SYSCALL feedback from Andrii Nakryiko. ]

Reported-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:52:58 -07:00
Zqiang
f596e2ce1c rcu: Use IRQ_WORK_INIT_HARD() to avoid rcu_read_unlock() hangs
When booting kernels built with both CONFIG_RCU_STRICT_GRACE_PERIOD=y
and CONFIG_PREEMPT_RT=y, the rcu_read_unlock_special() function's
invocation of irq_work_queue_on() the init_irq_work() causes the
rcu_preempt_deferred_qs_handler() function to work execute in SCHED_FIFO
irq_work kthreads.  Because rcu_read_unlock_special() is invoked on each
rcu_read_unlock() in such kernels, the amount of work just keeps piling
up, resulting in a boot-time hang.

This commit therefore avoids this hang by using IRQ_WORK_INIT_HARD()
instead of init_irq_work(), but only in kernels built with both
CONFIG_PREEMPT_RT=y and CONFIG_RCU_STRICT_GRACE_PERIOD=y.

Signed-off-by: Zqiang <qiang1.zhang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:51:11 -07:00
David Vernet
f1efe84d6f rcu_sync: Fix comment to properly reflect rcu_sync_exit() behavior
The rcu_sync_enter() function is used by updaters to force RCU readers
(e.g. percpu-rwsem) to use their slow paths during an update.  This is
accomplished by setting the ->gp_state of the rcu_sync structure to
GP_ENTER.  In the case of percpu-rwsem, the readers' slow path waits on
a semaphore instead of just incrementing a reader count.  Each updater
invokes the rcu_sync_exit() function to signal to readers that they
may again take their fastpaths.  The rcu_sync_exit() function sets the
->gp_state of the rcu_sync structure to GP_EXIT, and if all goes well,
after a grace period the ->gp_state reverts back to GP_IDLE.

Unfortunately, the rcu_sync_enter() function currently has a comment
incorrectly stating that rcu_sync_exit() (by an updater) will re-enable
reader "slowpaths".  This patch changes the comment to state that this
function re-enables reader fastpaths.

Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:51:11 -07:00
Zqiang
88ca472f80 rcu: Check for successful spawn of ->boost_kthread_task
For the spawning of the priority-boost kthreads can fail, improbable
though this might seem.  This commit therefore refrains from attemoting
to initiate RCU priority boosting when The ->boost_kthread_task pointer
is NULL.

Signed-off-by: Zqiang <qiang1.zhang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:51:11 -07:00
Frederic Weisbecker
70ae7b0ce0 rcu: Fix preemption mode check on synchronize_rcu[_expedited]()
An early check on synchronize_rcu[_expedited]() tries to determine if
the current CPU is in UP mode on an SMP no-preempt kernel, in which case
there is no need to start a grace period since the current assumed
quiescent state is all we need.

However the preemption mode doesn't take into account the boot selected
preemption mode under CONFIG_PREEMPT_DYNAMIC=y, missing a possible
early return if the running flavour is "none" or "voluntary".

Use the shiny new preempt mode accessors to fix this.  However,
avoid invoking them during early boot because doing so triggers a
WARN_ON_ONCE().

[ paulmck: Update for mainlined API. ]

Reported-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Uladzislau Rezki <uladzislau.rezki@sony.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:51:11 -07:00
Paul E. McKenney
80d530b47d rcu: Print number of online CPUs in RCU CPU stall-warning messages
RCU's synchronous grace periods act quite differently when there is
only one online CPU, especially in the no-op case in kernels built with
CONFIG_PREEMPTION=n.  This change in behavior can be important debugging
information, so this commit adds the number of online CPUs to the RCU
CPU stall warning messages.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:51:10 -07:00
Paul E. McKenney
75182a4eaa rcu: Add comments to final rcu_gp_cleanup() "if" statement
The final "if" statement in rcu_gp_cleanup() has proven to be rather
confusing, straightforward though it might have seemed when initially
written.  This commit therefore adds comments to its "then" and "else"
clauses to at least provide a more elevated form of confusion.

Reported-by: Boqun Feng <boqun.feng@gmail.com>
Reported-by: Frederic Weisbecker <frederic@kernel.org>
Reported-by: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Reported-by: Uladzislau Rezki <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:51:10 -07:00
Paul E. McKenney
3791a22374 kernel/smp: Provide boot-time timeout for CSD lock diagnostics
Debugging of problems involving insanely long-running SMI handlers
proceeds better if the CSD-lock timeout can be adjusted.  This commit
therefore provides a new smp.csd_lock_timeout kernel boot parameter
that specifies the timeout in milliseconds.  The default remains at the
previously hard-coded value of five seconds.

[ paulmck: Apply feedback from Juergen Gross. ]

Cc: Rik van Riel <riel@surriel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-04-20 16:50:30 -07:00
Damien Le Moal
1da18a296f zonefs: Fix management of open zones
The mount option "explicit_open" manages the device open zone
resources to ensure that if an application opens a sequential file for
writing, the file zone can always be written by explicitly opening
the zone and accounting for that state with the s_open_zones counter.

However, if some zones are already open when mounting, the device open
zone resource usage status will be larger than the initial s_open_zones
value of 0. Ensure that this inconsistency does not happen by closing
any sequential zone that is open when mounting.

Furthermore, with ZNS drives, closing an explicitly open zone that has
not been written will change the zone state to "closed", that is, the
zone will remain in an active state. Since this can then cause failures
of explicit open operations on other zones if the drive active zone
resources are exceeded, we need to make sure that the zone is not
active anymore by resetting it instead of closing it. To address this,
zonefs_zone_mgmt() is modified to change a REQ_OP_ZONE_CLOSE request
into a REQ_OP_ZONE_RESET for sequential zones that have not been
written.

Fixes: b5c00e9757 ("zonefs: open/close zone on file open/close")
Cc: <stable@vger.kernel.org>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com>
2022-04-21 08:39:20 +09:00
Damien Le Moal
694852ead2 zonefs: Clear inode information flags on inode creation
Ensure that the i_flags field of struct zonefs_inode_info is cleared to
0 when initializing a zone file inode, avoiding seeing the flag
ZONEFS_ZONE_OPEN being incorrectly set.

Fixes: b5c00e9757 ("zonefs: open/close zone on file open/close")
Cc: <stable@vger.kernel.org>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com>
2022-04-21 08:39:10 +09:00
Damien Le Moal
ae43038866 documentation: zonefs: Cleanup the mount options section
Use subsections to separate the descriptions of the "error=" and
"explicit-open" mount sections.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com>
2022-04-21 08:38:01 +09:00
Damien Le Moal
87c9ce3ffe zonefs: Add active seq file accounting
Modify struct zonefs_sb_info to add the s_active_seq_files atomic to
count the number of seq files representing a zone that is partially
written or explicitly open, that is, to count sequential files with
a zone that is in an active state on the device.

The helper function zonefs_account_active() is introduced to update
this counter whenever a file is written or truncated. This helper is
also used in the zonefs_seq_file_write_open() and
zonefs_seq_file_write_close() functions when the explicit_open mount
option is used.

The s_active_seq_files counter is exported through sysfs using the
read-only attribute nr_active_seq_files. The device maximum number of
active zones is also exported through sysfs with the read-only attribute
max_active_seq_files.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com>
2022-04-21 08:37:56 +09:00
Damien Le Moal
9277a6d4fb zonefs: Export open zone resource information through sysfs
To allow applications to easily check the current usage status of the
open zone resources of the mounted device, export through sysfs the
counter of write open sequential files s_wro_seq_files field of
struct zonefs_sb_info. The attribute is named nr_wro_seq_files and is
read only.

The maximum number of write open sequential files (zones) indicated by
the s_max_wro_seq_files field of struct zonefs_sb_info is also exported
as the read only attribute max_wro_seq_files.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com>
2022-04-21 08:37:51 +09:00
Damien Le Moal
7d6dfbe03b zonefs: Always do seq file write open accounting
The explicit_open mount option forces an explicitly open of the zone of
sequential files that are open for writing to ensure that the open file
can be written without the device failing write operations due to open
zone resources limit being exceeded. To implement this, zonefs accounts
all write open seq file when this mount option is used.

This accounting however can be easily performed even when the
explicit_open mount option is not used, thus allowing applications to
control zone resources on their own, without relying on open() system
call failures from zonefs.

To implement this, the helper zonefs_file_use_exp_open() is removed and
replaced with the helper zonefs_seq_file_need_wro() which test if a file
is a sequential file being open with write access. zonefs_open_zone()
and zonefs_close_zone() are renamed respectively to
zonefs_seq_file_write_open() and zonefs_seq_file_write_close() and
modified to update the s_wro_seq_files counter regardless of the
explicit_open mount option use.

If the explicit_open mount option is used, zonefs_seq_file_write_open()
execute an explicit zone open operation for a sequential file open for
writing for the first time, as before.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com>
2022-04-21 08:37:46 +09:00
Damien Le Moal
2b95a23c4f zonefs: Rename super block information fields
The s_open_zones field of struct zonefs_sb_info is used to count the
number of files that are open for writing and may not necessarilly
correspond to the number of open zones on the device. For instance, an
application may open for writing a sequential zone file, fully write it
and keep the file open. In such case, the zone of the file is not open
anymore (it is in the full state).

Avoid confusion about this counter meaning by renaming it to
s_wro_seq_files. To keep things consistent, the field s_max_open_zones
is renamed to s_max_wro_seq_files.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com>
2022-04-21 08:37:41 +09:00