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fd1dd7c398
Testing has shown that vfork() is actually significantly more efficient on systems where it's supported, even for copy-on-write implementations. If make is big enough, duplicating the page tables is significant overhead. * configure.ac: Check for fork/vfork. * makeint.h: Include vfork.h and set up #define for it. * os.h, posixos.c (get_bad_stdin): For children who can't use the normal stdin file descriptor, get a broken one. * job.c (start_job_command): Avoid so many ifdefs and simplify the invocation of child_execute_job() (child_execute_job): move the fork operation here so it can return early for the parent process. Switch to use vfork(). * function.c (func_shell_base): Use new child_execute_job() and simplify ifdefs. * job.h, main.c, remote-cstms.c, vmsjobs.c, w32os.c: Update declarations and calls.
85 lines
2.9 KiB
C
85 lines
2.9 KiB
C
/* Declarations for operating system interfaces for GNU Make.
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Copyright (C) 2016 Free Software Foundation, Inc.
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This file is part of GNU Make.
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GNU Make is free software; you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation; either version 3 of the License, or (at your option) any later
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version.
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GNU Make is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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this program. If not, see <http://www.gnu.org/licenses/>. */
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/* This section provides OS-specific functions to support the jobserver. */
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#ifdef MAKE_JOBSERVER
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/* Returns 1 if the jobserver is enabled, else 0. */
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unsigned int jobserver_enabled ();
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/* Called in the master instance to set up the jobserver initially. */
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void jobserver_setup (int job_slots);
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/* Called in a child instance to connect to the jobserver. */
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void jobserver_parse_arg (const char* arg);
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/* Returns an allocated buffer used to pass to child instances. */
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char *jobserver_get_arg ();
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/* Clear this instance's jobserver configuration. */
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void jobserver_clear ();
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/* Recover all the jobserver tokens and return the number we got. */
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unsigned int jobserver_acquire_all ();
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/* Release a jobserver token. If it fails and is_fatal is 1, fatal. */
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void jobserver_release (int is_fatal);
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/* Notify the jobserver that a child exited. */
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void jobserver_signal ();
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/* Get ready to start a non-recursive child. */
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void jobserver_pre_child ();
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/* Complete starting a non-recursive child. */
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void jobserver_post_child ();
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/* Set up to acquire a new token. */
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void jobserver_pre_acquire ();
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/* Wait until we can acquire a jobserver token.
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TIMEOUT is 1 if we have other jobs waiting for the load to go down;
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in this case we won't wait forever, so we can check the load.
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Returns 1 if we got a token, or 0 if we stopped waiting due to a child
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exiting or a timeout. */
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int jobserver_acquire (int timeout);
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#else
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#define jobserver_enabled() (0)
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#define jobserver_setup(_slots) (void)(0)
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#define jobserver_parse_arg(_arg) (void)(0)
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#define jobserver_get_arg() (NULL)
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#define jobserver_clear() (void)(0)
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#define jobserver_release(_fatal) (void)(0)
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#define jobserver_acquire_all() (0)
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#define jobserver_signal() (void)(0)
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#define jobserver_pre_child(_r) (void)(0)
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#define jobserver_post_child(_r) (void)(0)
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#define jobserver_pre_acquire() (void)(0)
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#define jobserver_acquire(_tmout) (0)
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#endif
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/* Create a "bad" file descriptor for stdin when parallel jobs are run. */
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#if !defined(VMD) && !defined(WINDOWS32) && !defined(_AMIGA) && !defined(__MSDOS__)
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int get_bad_stdin ();
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#else
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# define get_bad_stdin() (-1)
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#endif
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