diff options
Diffstat (limited to 'lib/PublicInbox/Spawn.pm')
| -rw-r--r-- | lib/PublicInbox/Spawn.pm | 63 |
1 files changed, 60 insertions, 3 deletions
diff --git a/lib/PublicInbox/Spawn.pm b/lib/PublicInbox/Spawn.pm index db679b77..50f31851 100644 --- a/lib/PublicInbox/Spawn.pm +++ b/lib/PublicInbox/Spawn.pm @@ -10,6 +10,9 @@ # daemons (inside the PSGI code (-httpd) and -nntpd). The short-lived # scripts (-mda, -index, -learn, -init) either use IPC::run or standard # Perl routines. +# +# There'll probably be more OS-level C stuff here, down the line. +# We don't want too many DSOs: https://udrepper.livejournal.com/8790.html package PublicInbox::Spawn; use strict; @@ -25,6 +28,7 @@ my $vfork_spawn = <<'VFORK_SPAWN'; #include <sys/resource.h> #include <unistd.h> #include <stdlib.h> +#include <errno.h> /* some platforms need alloca.h, but some don't */ #if defined(__GNUC__) && !defined(alloca) @@ -144,12 +148,51 @@ int pi_fork_exec(SV *redirref, SV *file, SV *cmdref, SV *envref, SV *rlimref, } VFORK_SPAWN +# btrfs on Linux is copy-on-write (COW) by default. As of Linux 5.7, +# this still leads to fragmentation for SQLite and Xapian files where +# random I/O happens, so we disable COW just for SQLite files and Xapian +# directories. Disabling COW disables checksumming, so we only do this +# for regeneratable files, and not canonical git storage (git doesn't +# checksum refs, only data under $GIT_DIR/objects). +my $set_nodatacow = $^O eq 'linux' ? <<'SET_NODATACOW' : ''; +#include <sys/ioctl.h> +#include <sys/vfs.h> +#include <linux/magic.h> +#include <linux/fs.h> +#include <errno.h> +#include <stdio.h> +#include <string.h> + +void set_nodatacow(int fd) +{ + struct statfs buf; + int val = 0; + + if (fstatfs(fd, &buf) < 0) { + fprintf(stderr, "fstatfs: %s\\n", strerror(errno)); + return; + } + + /* only btrfs is known to have this problem, so skip for non-btrfs */ + if (buf.f_type != BTRFS_SUPER_MAGIC) + return; + + if (ioctl(fd, FS_IOC_GETFLAGS, &val) < 0) { + fprintf(stderr, "FS_IOC_GET_FLAGS: %s\\n", strerror(errno)); + return; + } + val |= FS_NOCOW_FL; + if (ioctl(fd, FS_IOC_SETFLAGS, &val) < 0) + fprintf(stderr, "FS_IOC_SET_FLAGS: %s\\n", strerror(errno)); +} +SET_NODATACOW + my $inline_dir = $ENV{PERL_INLINE_DIRECTORY} //= ( $ENV{XDG_CACHE_HOME} // ( ($ENV{HOME} // '/nonexistent').'/.cache' ) ).'/public-inbox/inline-c'; -$vfork_spawn = undef unless -d $inline_dir && -w _; +$set_nodatacow = $vfork_spawn = undef unless -d $inline_dir && -w _; if (defined $vfork_spawn) { # Inline 0.64 or later has locking in multi-process env, # but we support 0.5 on Debian wheezy @@ -158,14 +201,21 @@ if (defined $vfork_spawn) { my $f = "$inline_dir/.public-inbox.lock"; open my $fh, '>', $f or die "failed to open $f: $!\n"; flock($fh, LOCK_EX) or die "LOCK_EX failed on $f: $!\n"; - eval 'use Inline C => $vfork_spawn'; + eval 'use Inline C => $vfork_spawn . $set_nodatacow'; my $err = $@; + my $ndc_err; + if ($err && $set_nodatacow) { # missing Linux kernel headers + $ndc_err = $err; + undef $set_nodatacow; + eval 'use Inline C => $vfork_spawn'; + } flock($fh, LOCK_UN) or die "LOCK_UN failed on $f: $!\n"; die $err if $err; + warn $ndc_err if $ndc_err; }; if ($@) { warn "Inline::C failed for vfork: $@\n"; - $vfork_spawn = undef; + $set_nodatacow = $vfork_spawn = undef; } } @@ -173,6 +223,13 @@ unless (defined $vfork_spawn) { require PublicInbox::SpawnPP; *pi_fork_exec = \&PublicInbox::SpawnPP::pi_fork_exec } +unless ($set_nodatacow) { + require PublicInbox::NDC_PP; + no warnings 'once'; + *set_nodatacow = \&PublicInbox::NDC_PP::set_nodatacow; +} +undef $set_nodatacow; +undef $vfork_spawn; sub which ($) { my ($file) = @_; |