From 0f461dcd3317f44670e2fc50346f87ff41e80127 Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Sun, 27 Dec 2020 02:53:07 +0000 Subject: ds: flatten + reuse @events, epoll_wait style fixes Consistently returning the equivalent of pollfd.revents in a portable manner was never worth the effort for us, as we use the same ->event_step callback regardless of POLLIN/POLLOUT/POLLHUP. Being a Perl, @events knows it size and we don't have to return a maximum index for the caller to iterate on. We can also avoid redundant integer coercion ("+0") since we ensure everything is an IV in other places. Finally, vec() is preferable to ("\0" x $size) for resizing buffers because it only needs to write the extended portion and not overwrite the entire buffer. --- lib/PublicInbox/Syscall.pm | 66 ++++++++++++++++++++++++++-------------------- 1 file changed, 37 insertions(+), 29 deletions(-) (limited to 'lib/PublicInbox/Syscall.pm') diff --git a/lib/PublicInbox/Syscall.pm b/lib/PublicInbox/Syscall.pm index e4f00a2a..c403f78a 100644 --- a/lib/PublicInbox/Syscall.pm +++ b/lib/PublicInbox/Syscall.pm @@ -227,38 +227,46 @@ sub epoll_ctl_mod8 { our $epoll_wait_events; our $epoll_wait_size = 0; sub epoll_wait_mod4 { - # resize our static buffer if requested size is bigger than we've ever done - if ($_[1] > $epoll_wait_size) { - $epoll_wait_size = $_[1]; - $epoll_wait_events = "\0" x 12 x $epoll_wait_size; - } - my $ct = syscall($SYS_epoll_wait, $_[0]+0, $epoll_wait_events, $_[1]+0, $_[2]+0); - for (0..$ct-1) { - @{$_[3]->[$_]}[1,0] = unpack("LL", substr($epoll_wait_events, 12*$_, 8)); - } - return $ct; + my ($epfd, $maxevents, $timeout_msec, $events) = @_; + # resize our static buffer if maxevents bigger than we've ever done + if ($maxevents > $epoll_wait_size) { + $epoll_wait_size = $maxevents; + vec($epoll_wait_events, $maxevents * 12 * 8 - 1, 1) = 0; + } + @$events = (); + my $ct = syscall($SYS_epoll_wait, $epfd, $epoll_wait_events, + $maxevents, $timeout_msec); + for (0..$ct - 1) { + # 12-byte struct epoll_event + # 4 bytes uint32_t events mask (skipped, useless to us) + # 8 bytes: epoll_data_t union (first 4 bytes are the fd) + # So we skip the first 4 bytes and take the middle 4: + $events->[$_] = unpack('L', substr($epoll_wait_events, + 12 * $_ + 4, 4)); + } } sub epoll_wait_mod8 { - # resize our static buffer if requested size is bigger than we've ever done - if ($_[1] > $epoll_wait_size) { - $epoll_wait_size = $_[1]; - $epoll_wait_events = "\0" x 16 x $epoll_wait_size; - } - my $ct; - if ($no_deprecated) { - $ct = syscall($SYS_epoll_wait, $_[0]+0, $epoll_wait_events, $_[1]+0, $_[2]+0, undef); - } else { - $ct = syscall($SYS_epoll_wait, $_[0]+0, $epoll_wait_events, $_[1]+0, $_[2]+0); - } - for (0..$ct-1) { - # 16 byte epoll_event structs, with format: - # 4 byte mask [idx 1] - # 4 byte padding (we put it into idx 2, useless) - # 8 byte data (first 4 bytes are fd, into idx 0) - @{$_[3]->[$_]}[1,2,0] = unpack("LLL", substr($epoll_wait_events, 16*$_, 12)); - } - return $ct; + my ($epfd, $maxevents, $timeout_msec, $events) = @_; + + # resize our static buffer if maxevents bigger than we've ever done + if ($maxevents > $epoll_wait_size) { + $epoll_wait_size = $maxevents; + vec($epoll_wait_events, $maxevents * 16 * 8 - 1, 1) = 0; + } + @$events = (); + my $ct = syscall($SYS_epoll_wait, $epfd, $epoll_wait_events, + $maxevents, $timeout_msec, + $no_deprecated ? undef : ()); + for (0..$ct - 1) { + # 16-byte struct epoll_event + # 4 bytes uint32_t events mask (skipped, useless to us) + # 4 bytes padding (skipped, useless) + # 8 bytes epoll_data_t union (first 4 bytes are the fd) + # So skip the first 8 bytes, take 4, and ignore the last 4: + $events->[$_] = unpack('L', substr($epoll_wait_events, + 16 * $_ + 8, 4)); + } } sub signalfd ($$$) { -- cgit v1.2.3-24-ge0c7