Messages in this thread | | | From | David Howells <> | Subject | Re: [PATCH v3 2/2] iov_iter: Don't deal with iter->copy_mc in memcpy_from_iter_mc() | Date | Fri, 18 Aug 2023 14:33:35 +0100 |
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Linus Torvalds <torvalds@linux-foundation.org> wrote:
> This patch only does that for the 'user_backed' thing, which was a similar > case.
It makes some things a bit bigger, makes some a bit smaller:
__iov_iter_get_pages_alloc dcr 0x331 -> 0x32a -0x7 _copy_from_iter dcr 0x36e -> 0x36a -0x4 _copy_from_iter_flushcache inc 0x359 -> 0x36b +0x12 _copy_mc_to_iter dcr 0x3a7 -> 0x39b -0xc _copy_to_iter inc 0x358 -> 0x359 +0x1 copy_page_to_iter_nofault.part.0 dcr 0x3f1 -> 0x3ef -0x2 csum_and_copy_from_iter dcr 0x3e8 -> 0x3e4 -0x4 csum_and_copy_to_iter inc 0x46a -> 0x46d +0x3 dup_iter inc 0x34 -> 0x39 +0x5 fault_in_iov_iter_readable inc 0x9b -> 0xa0 +0x5 fault_in_iov_iter_writeable inc 0x9b -> 0xa0 +0x5 first_iovec_segment inc 0x4a -> 0x51 +0x7 import_single_range dcr 0x62 -> 0x40 -0x22 import_ubuf dcr 0x65 -> 0x43 -0x22 iov_iter_advance inc 0xd7 -> 0x103 +0x2c iov_iter_alignment inc 0xe0 -> 0xe2 +0x2 iov_iter_extract_pages dcr 0x418 -> 0x416 -0x2 iov_iter_init dcr 0x31 -> 0x27 -0xa iov_iter_is_aligned inc 0xf3 -> 0x108 +0x15 iov_iter_npages inc 0x119 -> 0x11a +0x1 iov_iter_revert inc 0x88 -> 0x99 +0x11 iov_iter_single_seg_count inc 0x38 -> 0x3e +0x6 iov_iter_ubuf new 0x39 iov_iter_zero inc 0x34f -> 0x353 +0x4 iter_iov new 0x17
Adding an extra patch to get rid of the bitfields and using a u8 for the type and bools for the flags makes very little difference on top of the above:
__iov_iter_get_pages_alloc inc 0x32a -> 0x32f +0x5 _copy_from_iter inc 0x36a -> 0x36d +0x3 copy_page_from_iter_atomic.part.0 inc 0x3cf -> 0x3d2 +0x3 csum_and_copy_to_iter dcr 0x46d -> 0x46a -0x3 iov_iter_advance dcr 0x103 -> 0xfd -0x6 iov_iter_extract_pages inc 0x416 -> 0x417 +0x1 iov_iter_init inc 0x27 -> 0x2d +0x6 iov_iter_revert dcr 0x99 -> 0x95 -0x4
For reference, I generated the stats with:
nm build3/lib/iov_iter.o | sort >a ... change... nm build3/lib/iov_iter.o | sort >b perl analyse.pl a b
where analyse.pl is attached.
David --- #!/usr/bin/perl -w use strict;
die "$0 <file_a> <file_b>" if ($#ARGV != 1); my ($file_a, $file_b) = @ARGV; die "$file_a: File not found\n" unless -r $file_a; die "$file_b: File not found\n" unless -r $file_b;
my %a = (); my %b = (); my %c = ();
sub read_one($$$) { my ($file, $list, $all) = @_; my $last = undef;
open FD, "<$file" || die $file; while (<FD>) { if (/([0-9a-f][0-9a-f]+) [Tt] ([_a-zA-Z0-9.]*)/) { my $addr = hex $1; my $sym = $2; #print $addr, " ", $sym, "\n";
my %obj = ( sym => $sym, addr => $addr, size => 0 );
$list->{$sym} = \%obj; $all->{$sym} = 1;
if ($last) { $last->{size} = $addr - $last->{addr}; }
$last = \%obj; } } close(FD); }
read_one($file_a, \%a, \%c); read_one($file_b, \%b, \%c);
foreach my $sym (sort keys %c) { my $as = -1; my $bs = -1;
$as = $a{$sym}->{size} if (exists($a{$sym})); $bs = $b{$sym}->{size} if (exists($b{$sym}));
next if ($as == $bs); #next if ($sym =~ /__UNIQUE_ID/);
if ($as == -1) { printf "%-40s new 0x%x\n", $sym, $bs; } elsif ($bs == -1) { printf "%-40s del 0x%x\n", $sym, $as; } elsif ($bs > $as) { printf "%-40s inc 0x%x -> 0x%x +0x%x\n", $sym, $as, $bs, $bs - $as; } else { printf "%-40s dcr 0x%x -> 0x%x -0x%x\n", $sym, $as, $bs, $as - $bs; } }
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