From 933fce93167eba8645e637c363561575db9f9420 Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Sat, 26 Dec 2020 09:34:39 +0000 Subject: inboxidle: avoid needless syscalls on refresh We don't have to replace a bunch of existing watches with identical new ones. On Linux with Linux::Inotify2 installed, this avoids a storm of inotify_add_watch(2) and inotify_rm_watch(2) syscalls on SIGHUP with -imapd and "-extindex --watch" (cherry picked from commit 10bf54305da8422d9ece6b809996092c1c4b1786) Note: this seems to fix missed wakeups with many watches, so it's in the stable branch. Link: https://public-inbox.org/meta/20201226201115.GA30142@dcvr/ --- lib/PublicInbox/InboxIdle.pm | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'lib') diff --git a/lib/PublicInbox/InboxIdle.pm b/lib/PublicInbox/InboxIdle.pm index 357bd216..60948bea 100644 --- a/lib/PublicInbox/InboxIdle.pm +++ b/lib/PublicInbox/InboxIdle.pm @@ -30,17 +30,26 @@ sub in2_arm ($$) { # PublicInbox::Config::each_inbox callback } my $inot = $self->{inot}; my $cur = $self->{pathmap}->{$dir} //= []; + my $lock = "$dir/".($ibx->version >= 2 ? 'inbox.lock' : 'ssoma.lock'); # transfer old subscriptions to the current inbox, cancel the old watch - if (my $old_ibx = $cur->[0]) { + my $old_ibx = $cur->[0]; + $cur->[0] = $ibx; + if ($old_ibx) { $ibx->{unlock_subs} and die "BUG: $dir->{unlock_subs} should not exist"; $ibx->{unlock_subs} = $old_ibx->{unlock_subs}; + + # Linux::Inotify2::Watch::name matches if watches are the + # same, no point in replacing a watch of the same name + if ($cur->[1]->name eq $lock) { + $self->{on_unlock}->{$lock} = $ibx; + return; + } + # rare, name changed (v1 inbox converted to v2) $cur->[1]->cancel; # Linux::Inotify2::Watch::cancel } - $cur->[0] = $ibx; - my $lock = "$dir/".($ibx->version >= 2 ? 'inbox.lock' : 'ssoma.lock'); if (my $w = $cur->[1] = $inot->watch($lock, $IN_MODIFY)) { $self->{on_unlock}->{$w->name} = $ibx; } else { -- cgit v1.2.3-24-ge0c7