Commit Graph

1561 Commits

Author SHA1 Message Date
Nicolas Saenz Julienne
71ad4713cc util/event-loop-base: Introduce options to set the thread pool size
The thread pool regulates itself: when idle, it kills threads until
empty, when in demand, it creates new threads until full. This behaviour
doesn't play well with latency sensitive workloads where the price of
creating a new thread is too high. For example, when paired with qemu's
'-mlock', or using safety features like SafeStack, creating a new thread
has been measured take multiple milliseconds.

In order to mitigate this let's introduce a new 'EventLoopBase'
property to set the thread pool size. The threads will be created during
the pool's initialization or upon updating the property's value, remain
available during its lifetime regardless of demand, and destroyed upon
freeing it. A properly characterized workload will then be able to
configure the pool to avoid any latency spikes.

Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-id: 20220425075723.20019-4-nsaenzju@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2022-05-09 10:43:23 +01:00
Nicolas Saenz Julienne
70ac26b9e5 util/main-loop: Introduce the main loop into QOM
'event-loop-base' provides basic property handling for all 'AioContext'
based event loops. So let's define a new 'MainLoopClass' that inherits
from it. This will permit tweaking the main loop's properties through
qapi as well as through the command line using the '-object' keyword[1].
Only one instance of 'MainLoopClass' might be created at any time.

'EventLoopBaseClass' learns a new callback, 'can_be_deleted()' so as to
mark 'MainLoop' as non-deletable.

[1] For example:
      -object main-loop,id=main-loop,aio-max-batch=<value>

Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-id: 20220425075723.20019-3-nsaenzju@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2022-05-09 10:43:23 +01:00
Stefan Hajnoczi
c1fe694357 coroutine-win32: use QEMU_DEFINE_STATIC_CO_TLS()
Thread-Local Storage variables cannot be used directly from coroutine
code because the compiler may optimize TLS variable accesses across
qemu_coroutine_yield() calls. When the coroutine is re-entered from
another thread the TLS variables from the old thread must no longer be
used.

Use QEMU_DEFINE_STATIC_CO_TLS() for the current and leader variables.

I think coroutine-win32.c could get away with __thread because the
variables are only used in situations where either the stale value is
correct (current) or outside coroutine context (loading leader when
current is NULL). Due to the difficulty of being sure that this is
really safe in all scenarios it seems worth converting it anyway.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20220307153853.602859-4-stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-05-04 15:55:23 +02:00
Stefan Hajnoczi
ac387a08a9 coroutine: use QEMU_DEFINE_STATIC_CO_TLS()
Thread-Local Storage variables cannot be used directly from coroutine
code because the compiler may optimize TLS variable accesses across
qemu_coroutine_yield() calls. When the coroutine is re-entered from
another thread the TLS variables from the old thread must no longer be
used.

Use QEMU_DEFINE_STATIC_CO_TLS() for the current and leader variables.
The alloc_pool QSLIST needs a typedef so the return value of
get_ptr_alloc_pool() can be stored in a local variable.

One example of why this code is necessary: a coroutine that yields
before calling qemu_coroutine_create() to create another coroutine is
affected by the TLS issue.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20220307153853.602859-3-stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-05-04 15:55:23 +02:00
Stefan Hajnoczi
34145a307d coroutine-ucontext: use QEMU_DEFINE_STATIC_CO_TLS()
Thread-Local Storage variables cannot be used directly from coroutine
code because the compiler may optimize TLS variable accesses across
qemu_coroutine_yield() calls. When the coroutine is re-entered from
another thread the TLS variables from the old thread must no longer be
used.

Use QEMU_DEFINE_STATIC_CO_TLS() for the current and leader variables.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20220307153853.602859-2-stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-05-04 15:55:23 +02:00
Marc-André Lureau
ff5927baa7 util: rename qemu_*block() socket functions
The qemu_*block() functions are meant to be be used with sockets (the
win32 implementation expects SOCKET)

Over time, those functions where used with Win32 SOCKET or
file-descriptors interchangeably. But for portability, they must only be
used with socket-like file-descriptors. FDs can use
g_unix_set_fd_nonblocking() instead.

Rename the functions with "socket" in the name to prevent bad usages.

This is effectively reverting commit f9e8cacc55 ("oslib-posix:
rename socket_set_nonblock() to qemu_set_nonblock()").

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2022-05-03 15:53:20 +04:00
Marc-André Lureau
22e135fca3 Replace fcntl(O_NONBLOCK) with g_unix_set_fd_nonblocking()
Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2022-05-03 15:47:38 +04:00
Marc-André Lureau
81badab381 util: replace pipe()+cloexec with g_unix_open_pipe()
Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2022-05-03 15:18:14 +04:00
Marc-André Lureau
a7241974ce Replace qemu_pipe() with g_unix_open_pipe()
GLib g_unix_open_pipe() is essentially like qemu_pipe(), available since
2.30.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2022-05-03 15:17:56 +04:00
Marc-André Lureau
ad24b679d2 block: move fcntl_setfl()
It is only used by block/file-posix.c, move it there.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2022-05-03 15:17:53 +04:00
Marc-André Lureau
4d14cb0cd7 Use g_unix_set_fd_nonblocking()
API available since glib 2.30. It also preserves errno.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2022-05-03 15:17:30 +04:00
Marc-André Lureau
638466f777 Use QEMU_SANITIZE_ADDRESS
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
2022-05-03 15:16:23 +04:00
Paolo Bonzini
7544060ef3 meson, configure: move libgio test to meson
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-28 08:52:22 +02:00
Paolo Bonzini
e960a7ee46 remove -writeconfig
Like -set and -readconfig, it would not really be too hard to
extend -writeconfig to parsing mechanisms other than QemuOpts.
However, the uses of -writeconfig are substantially more
limited, as it is generally easier to write the configuration
by hand in the first place.  In addition, -writeconfig does
not even try to detect cases where it prints incorrect
syntax (for example if values have a quote in them, since
qemu_config_parse does not support any kind of escaping.
Just remove it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220414145721.326866-1-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-28 08:51:56 +02:00
Haiyue Wang
5c08edd1fa error-report: fix g_date_time_format assertion
The 'g_get_real_time' returns the number of microseconds since January
1, 1970 UTC, but 'g_date_time_new_from_unix_utc' needs the number of
seconds, so it will cause the invalid time input:

(process:279642): GLib-CRITICAL (recursed) **: g_date_time_format: assertion 'datetime != NULL' failed

Call function 'g_date_time_new_now_utc' instead, it has the same result
as 'g_date_time_new_from_unix_utc(g_get_real_time() / G_USEC_PER_SEC)';

Fixes: 73dab893b5 ("error-report: replace deprecated g_get_current_time() with glib >= 2.62")
Signed-off-by: Haiyue Wang <haiyue.wang@intel.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20220424105036.291370-1-haiyue.wang@intel.com>
2022-04-28 08:51:56 +02:00
Daniel P. Berrangé
c6b310b37c softmmu: remove deprecated --enable-fips option
Users requiring FIPS support must build QEMU with either the libgcrypt
or gnutls libraries as the crytography backend.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2022-04-26 16:12:25 +01:00
Marc-André Lureau
1fbf2665e6 util: replace qemu_get_local_state_pathname()
Simplify the function to only return the directory path. Callers are
adjusted to use the GLib function to build paths, g_build_filename().

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220420132624.2439741-39-marcandre.lureau@redhat.com>
2022-04-21 17:09:09 +04:00
Marc-André Lureau
1b34d08f0b util: use qemu_create() in qemu_write_pidfile()
qemu_open_old(O_CREATE) should be replaced with qemu_create() which
handles Error reporting.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220420132624.2439741-38-marcandre.lureau@redhat.com>
2022-04-21 17:09:09 +04:00
Marc-André Lureau
96eb9b2b47 util: use qemu_write_full() in qemu_write_pidfile()
Mostly for correctness.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220420132624.2439741-37-marcandre.lureau@redhat.com>
2022-04-21 17:09:09 +04:00
Marc-André Lureau
d0dedf2f4c util: simplify write in signal handler
Use qemu_write_full() instead of open-coding a write loop.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220420132624.2439741-36-marcandre.lureau@redhat.com>
2022-04-21 17:09:09 +04:00
Marc-André Lureau
548fb0da73 qga: move qga_get_host_name()
The function is specific to qemu-ga, no need to share it in QEMU.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
Message-Id: <20220420132624.2439741-32-marcandre.lureau@redhat.com>
2022-04-21 17:09:09 +04:00
Marc-André Lureau
756a98dd70 Move error_printf_unless_qmp() with monitor unit
Since it depends on monitor code, and error_vprintf_unless_qmp() is
already there.

This will help to move error-report in a common subproject.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220420132624.2439741-31-marcandre.lureau@redhat.com>
2022-04-21 17:09:09 +04:00
Marc-André Lureau
9ca9c893b6 include: add qemu/keyval.h
Do not require the whole option machinery to handle keyval, as it is
used by QAPI alone, without the option API. And match the associated
unit name.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220420132624.2439741-24-marcandre.lureau@redhat.com>
2022-04-21 17:03:51 +04:00
Marc-André Lureau
282468c7c4 include: move qemu_fdatasync() to osdep
Move QEMU-specific code to util/osdep.c, so cutils can become a common
subproject.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220420132624.2439741-22-marcandre.lureau@redhat.com>
2022-04-21 17:03:51 +04:00
Marc-André Lureau
73991a9222 include: move qemu_msync() to osdep
The implementation depends on the OS. (and longer-term goal is to move
cutils to a common subproject)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220420132624.2439741-21-marcandre.lureau@redhat.com>
2022-04-21 17:03:51 +04:00
Marc-André Lureau
951cc9df88 glib-compat: isolate g_date_time_format_iso8601 version-bypass
The solution was discussed with Markus Armbruster during the review:
https://patchew.org/QEMU/20220323155743.1585078-1-marcandre.lureau@redhat.com/20220323155743.1585078-14-marcandre.lureau@redhat.com/

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220420132624.2439741-3-marcandre.lureau@redhat.com>
2022-04-21 16:56:55 +04:00
Richard Henderson
4e51069d67 util/log: Support per-thread log files
Add a new log flag, tid, to turn this feature on.
Require the log filename to be set, and to contain %d.

Do not allow tid to be turned off once it is on, nor let
the filename be change thereafter.  This avoids the need
for signalling each thread to re-open on a name change.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-40-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
30f5a73ac3 util/log: Limit RCUCloseFILE to file closing
Use FILE* for global_file.  We can perform an rcu_read on that
just as easily as RCUCloseFILE*.  This simplifies a couple of
places, where previously we required taking the rcu_read_lock
simply to avoid racing to dereference RCUCloseFile->fd.

Only allocate the RCUCloseFile prior to call_rcu.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-39-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
d5f55fff34 util/log: Rename QemuLogFile to RCUCloseFILE
s/QemuLogFile/RCUCloseFILE/
s/qemu_logfile_free/rcu_close_file/

Emphasize that this is only a carrier for passing a pointer
to call_rcu for closing, and not the real logfile.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-38-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
92b24cb77f util/log: Combine two logfile closes
Merge the close from the changed_name block with the close
from the !need_to_open_file block.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-37-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
beab3447db util/log: Hoist the eval of is_daemonized in qemu_set_log_internal
Only call is_daemonized once.
We require the result on all paths after this point.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-36-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
702979f736 util/log: Rename qemu_logfile_mutex to global_mutex
Rename to emphasize this covers the file-scope global variables.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-35-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
8ae58d6009 util/log: Rename qemu_logfile to global_file
Rename to emphasize this is the file-scope global variable.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-34-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
4226646481 util/log: Rename logfilename to global_filename
Rename to emphasize this is the file-scope global variable.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-33-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
ec0d1849d9 util/log: Remove qemu_log_close
The only real use is in cpu_abort, where we have just
flushed the file via qemu_log_unlock, and are just about
to force-crash the application via abort.  We do not
really need to close the FILE before the abort.

The two uses in test-logging.c can be handled with
qemu_set_log_filename_flags.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-32-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
144539d360 util/log: Introduce qemu_set_log_filename_flags
Provide a function to set both filename and flags at
the same time.  This is the common case at startup.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-28-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
7fc493f8bd include/qemu/log: Move entire implementation out-of-line
Move QemuLogFile, qemu_logfile, and all inline functions into qemu/log.c.
No need to expose these implementation details in the api.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-26-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
fb6efecf54 util/log: Drop call to setvbuf
Now that the log buffer is flushed after every qemu_log_unlock,
which includes every call to qemu_log, we do not need to force
line buffering (or unbuffering for windows).  Block buffer the
entire loggable unit.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-21-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
90f37362d7 util/log: Remove qemu_log_flush
All uses flush output immediately before or after qemu_log_unlock.
Instead of a separate call, move the flush into qemu_log_unlock.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-20-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
3c06a41746 util/log: Drop return value from qemu_log
The only user of this feature, tcg_dump_ops, has been
converted to use fprintf directly.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-18-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
095e9855b7 util/log: Use qemu_log_trylock/unlock in qemu_log
Avoid using QemuLogFile and RCU directly.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-17-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
c60f599bcb util/log: Rename qemu_log_lock to qemu_log_trylock
This function can fail, which makes it more like ftrylockfile
or pthread_mutex_trylock than flockfile or pthread_mutex_lock,
so rename it.

To closer match the other trylock functions, release rcu_read_lock
along the failure path, so that qemu_log_unlock need not be called
on failure.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-8-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
c59fe6e536 util/log: Move qemu_log_lock, qemu_log_unlock out of line
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-7-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
c5955f4ff4 util/log: Pass Error pointer to qemu_set_log
Do not force exit within qemu_set_log; return bool and pass
an Error value back up the stack as per usual.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-5-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
e2c7c6a454 util/log: Return bool from qemu_set_log_filename
Per the recommendations in qapi/error.h, return false on failure.

Use the return value in the monitor, the only place we aren't
already passing error_fatal or error_abort.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-4-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Richard Henderson
54ee5b3da0 util/log: Drop manual log buffering
This buffering was introduced during the Paleozoic: 9fa3e85353.

There has never been an explanation as to why we may not allow
glibc to allocate the file buffer itself.  We certainly have
many other uses of mmap and malloc during user-only startup,
so presumably whatever the issue was, it has been fixed during
the preceeding 18 years.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220417183019.755276-2-richard.henderson@linaro.org>
2022-04-20 10:51:11 -07:00
Paolo Bonzini
8ab3026489 thread-posix: optimize qemu_sem_timedwait with zero timeout
In this case there is no need to call pthread_cond_timedwait; the
function is just a trywait and waiting on the condition variable would
always time out.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-06 14:31:56 +02:00
Longpeng(Mike)
a0d45db854 thread-posix: implement Semaphore with QemuCond and QemuMutex
Now that QemuSemaphore is implemented through pthread_cond_t only, we can use
QemuCond and QemuMutex to make the code smaller.  Features such as mutex
tracing and CLOCK_MONOTONIC timedwait are supported in qemu-sem naturally.

Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Message-Id: <20220222090507.2028-4-longpeng2@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-06 14:31:56 +02:00
Longpeng(Mike)
657ac98b58 thread-posix: use monotonic clock for QemuCond and QemuSemaphore
Use CLOCK_MONOTONIC, so the timeout isn't affected by changes to
the system time. It depends on the pthread_condattr_setclock(),
while some systems(e.g. mac os) does not support it, so the behavior
won't change in these systems.

Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Message-Id: <20220222090507.2028-3-longpeng2@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-06 14:31:56 +02:00
Longpeng(Mike)
f9fc8932b1 thread-posix: remove the posix semaphore support
POSIX specifies an absolute time for sem_timedwait(), it would be
affected if the system time is changing, but there is not a relative
time or monotonic clock version of sem_timedwait, so we cannot gain
from POSIX semaphore any more.

An alternative way is to use sem_trywait + usleep, maybe we can
remove CONFIG_SEM_TIMEDWAIT in this way? No, because some systems
(e.g. mac os) mark the sem_xxx API as deprecated.

So maybe remove the usage of POSIX semaphore and turn to use the
pthread variant for all systems looks better.

Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Message-Id: <20220222090507.2028-2-longpeng2@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-06 14:31:55 +02:00