git-svn: reduce memory usage for large commits

apply_textdelta and send_stream can use a separate pool from the
rest of the editor interface, so we'll use a separate SVN::Pool
for them and clear the pool after each file is sent to SVN.

This drastically reduces memory usage per-changeset committed,
and makes large commits (and initial imports) of several
thousand files possible.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git-svn.perl

@@ -3354,9 +3354,11 @@ sub chg_file {
 	seek $fh, 0, 0 or croak $!;
 
 	my $exp = $md5->hexdigest;
-	my $atd = $self->apply_textdelta($fbat, undef, $self->{pool});
-	my $got = SVN::TxDelta::send_stream($fh, @$atd, $self->{pool});
+	my $pool = SVN::Pool->new;
+	my $atd = $self->apply_textdelta($fbat, undef, $pool);
+	my $got = SVN::TxDelta::send_stream($fh, @$atd, $pool);
 	die "Checksum mismatch\nexpected: $exp\ngot: $got\n" if ($got ne $exp);
+	$pool->clear;
 
 	close $fh or croak $!;
 }