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https://github.com/libguestfs/libguestfs.git
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166ac594cc
The maxrss is described in getrusage(2) as "This is the maximum resident set size used (in kilobytes).". This lets us find out how much memory qemu really used, and is useful for determining if memory minimization techniques such as DAX are having any effect.
88 lines
2.5 KiB
C
88 lines
2.5 KiB
C
/* libguestfs
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* Copyright (C) 2016 Red Hat Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/time.h>
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#include <sys/resource.h>
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#include <sys/wait.h>
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#include "guestfs.h"
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#include "guestfs-internal.h"
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/**
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* A safe version of L<waitpid(3)> which retries if C<EINTR> is
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* returned.
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*
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* I<Note:> this only needs to be used in the library, or in programs
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* that install a non-restartable C<SIGCHLD> handler (which is not the
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* case for any current libguestfs virt tools).
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*
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* If the main program installs a SIGCHLD handler and sets it to be
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* non-restartable, then what can happen is the library is waiting in
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* a wait syscall, the child exits, C<SIGCHLD> is sent to the process,
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* and the wait syscall returns C<EINTR>. Since the library cannot
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* control the signal handler, we have to instead restart the wait
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* syscall, which is the purpose of this wrapper.
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*/
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int
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guestfs_int_waitpid (guestfs_h *g, pid_t pid, int *status, const char *errmsg)
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{
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again:
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if (waitpid (pid, status, 0) == -1) {
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if (errno == EINTR)
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goto again;
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perrorf (g, "%s: waitpid", errmsg);
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return -1;
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}
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return 0;
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}
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/**
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* Like C<guestfs_int_waitpid>, but ignore errors.
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*/
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void
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guestfs_int_waitpid_noerror (pid_t pid)
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{
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while (waitpid (pid, NULL, 0) == -1 && errno == EINTR)
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;
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}
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/**
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* A safe version of L<wait4(2)> which retries if C<EINTR> is
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* returned.
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*/
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int
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guestfs_int_wait4 (guestfs_h *g, pid_t pid, int *status,
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struct rusage *rusage, const char *errmsg)
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{
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again:
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if (wait4 (pid, status, 0, rusage) == -1) {
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if (errno == EINTR)
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goto again;
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perrorf (g, "%s: wait4", errmsg);
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return -1;
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}
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return 0;
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}
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