From d720518f39c7716e3fe21fb4976b5b25d6365d20 Mon Sep 17 00:00:00 2001 From: Jason Merrill Date: Mon, 21 Oct 2019 23:09:41 -0400 Subject: [PATCH] lock-and-run.sh: Check for process existence rather than timeout. * lock-and-run.sh: Check for process existence rather than timeout. Matthias Klose noted that on less powerful targets, a link might take more than 5 minutes; he mentions a figure of 3 hours for an LTO link. So this patch changes the timeout to a check for whether the locking process still exists. If the lock exists in an erroneous state (no pid file or can't signal the pid) for 30 sec, steal it. From-SVN: r277277 --- gcc/ChangeLog | 4 ++++ gcc/lock-and-run.sh | 40 ++++++++++++++++++++++++++++------------ 2 files changed, 32 insertions(+), 12 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 2aa5536cf32..5e6c6620d17 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,7 @@ +2019-10-21 Jason Merrill + + * lock-and-run.sh: Check for process existence rather than timeout. + 2019-10-21 Jozef Lawrynowicz * expr.c (expand_expr_real_2): Don't widen constant op1 when expanding diff --git a/gcc/lock-and-run.sh b/gcc/lock-and-run.sh index 3a6a84c253a..22bc436565c 100644 --- a/gcc/lock-and-run.sh +++ b/gcc/lock-and-run.sh @@ -1,33 +1,49 @@ #! /bin/sh -# Shell-based mutex using mkdir. +# Shell-based mutex using mkdir. This script is used in make to prefer +# serialized execution to avoid consuming too much RAM. If reusing it, +# bear in mind that the lock-breaking logic is not race-free, so disable +# it in err() if concurrent execution could cause more serious problems. +self=`basename $0` lockdir="$1" prog="$2"; shift 2 || exit 1 # Remember when we started trying to acquire the lock. count=0 -touch lock-stamp.$$ -trap 'rm -r "$lockdir" lock-stamp.$$' 0 +err () { + if test -f $lockdir/lock-$1.$$; then + echo "$self: *** (PID $$) removing stale $lockdir" >&2 + rm -rf $lockdir + # Possible variant for uses where races are more problematic: + #echo "$self: *** (PID $$) giving up, maybe rm -r $lockdir" >&2 + #exit 42 + else + touch $lockdir/lock-$1.$$ + fi +} until mkdir "$lockdir" 2>/dev/null; do # Say something periodically so the user knows what's up. if [ `expr $count % 30` = 0 ]; then - # Reset if the lock has been renewed. - if [ -n "`find \"$lockdir\" -newer lock-stamp.$$`" ]; then - touch lock-stamp.$$ - count=1 - # Steal the lock after 5 minutes. - elif [ $count = 300 ]; then - echo removing stale $lockdir >&2 - rm -r "$lockdir" + # Check for valid lock. + if pid=`cat $lockdir/pid 2>/dev/null` && kill -0 $pid 2>/dev/null; then + echo "$self: (PID $$) waiting $count sec to acquire $lockdir from PID $pid" >&2 + elif test -z "$pid"; then + echo "$self: (PID $$) cannot read $lockdir/pid" >&2 + err nopid else - echo waiting to acquire $lockdir >&2 + echo "$self: (PID $$) cannot signal $lockdir owner PID $pid" >&2 + err dead fi fi sleep 1 count=`expr $count + 1` done +trap 'rm -rf "$lockdir"' 0 +echo $$ > $lockdir/pidT && mv $lockdir/pidT $lockdir/pid +echo "$self: (PID $$) acquired $lockdir after $count seconds" >&2 + echo $prog "$@" $prog "$@" -- 2.30.2