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Refactor internal-signals.h

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The main drive is to optimize the internal usage and required size
when sigset_t is embedded in other data structures.  On Linux, the
current supported signal set requires up to 8 bytes (16 on mips),
was lower than the user defined sigset_t (128 bytes).

A new internal type internal_sigset_t is added, along with the
functions to operate on it similar to the ones for sigset_t.  The
internal-signals.h is also refactored to remove unused functions

Besides small stack usage on some functions (posix_spawn, abort)
it lower the struct pthread by about 120 bytes (112 on mips).

Checked on x86_64-linux-gnu.

Reviewed-by: Arjun Shankar <arjun@redhat.com>
This commit is contained in:
Adhemerval Zanella
2022-04-21 09:41:59 -03:00
parent c22d2021a9
commit a1bdd81664
18 changed files with 184 additions and 98 deletions
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16
nptl/pthread_create.c
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@@ -423,7 +423,7 @@ start_thread (void *arg)
/* Store the new cleanup handler info. */
THREAD_SETMEM (pd, cleanup_jmp_buf, &unwind_buf);
__libc_signal_restore_set (&pd->sigmask);
internal_signal_restore_set (&pd->sigmask);
LIBC_PROBE (pthread_start, 3, (pthread_t) pd, pd->start_routine, pd->arg);
@@ -501,8 +501,8 @@ start_thread (void *arg)
signal to be delivered. (SIGSETXID cannot run application code,
nor does it use pthread_kill.) Reuse the pd->sigmask space for
computing the signal mask, to save stack space. */
__sigfillset (&pd->sigmask);
__sigdelset (&pd->sigmask, SIGSETXID);
internal_sigfillset (&pd->sigmask);
internal_sigdelset (&pd->sigmask, SIGSETXID);
INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_BLOCK, &pd->sigmask, NULL,
__NSIG_BYTES);
@@ -769,14 +769,14 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
/* Block all signals, so that the new thread starts out with
signals disabled. This avoids race conditions in the thread
startup. */
sigset_t original_sigmask;
__libc_signal_block_all (&original_sigmask);
internal_sigset_t original_sigmask;
internal_signal_block_all (&original_sigmask);
if (iattr->extension != NULL && iattr->extension->sigmask_set)
/* Use the signal mask in the attribute. The internal signals
have already been filtered by the public
pthread_attr_setsigmask_np interface. */
pd->sigmask = iattr->extension->sigmask;
internal_sigset_from_sigset (&pd->sigmask, &iattr->extension->sigmask);
else
{
/* Conceptually, the new thread needs to inherit the signal mask
@@ -786,7 +786,7 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
pd->sigmask = original_sigmask;
/* Reset the cancellation signal mask in case this thread is
running cancellation. */
__sigdelset (&pd->sigmask, SIGCANCEL);
internal_sigdelset (&pd->sigmask, SIGCANCEL);
}
/* Start the thread. */
@@ -833,7 +833,7 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
/* Return to the previous signal mask, after creating the new
thread. */
__libc_signal_restore_set (&original_sigmask);
internal_signal_restore_set (&original_sigmask);
if (__glibc_unlikely (retval != 0))
{