On Fri, 2022-08-05 at 17:07 -0700, Andrew Morton wrote: > On Fri, 5 Aug 2022 17:04:28 -0700 Roman Gushchin <roman.gushchin@xxxxxxxxx> wrote: > > > On Fri, Aug 05, 2022 at 04:32:34PM -0700, Linus Torvalds wrote: > > > On Wed, Aug 3, 2022 at 1:35 PM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > > > > > - memcg debug/visibility work from Roman Gushchin > > > > > > Well, not just memcg. > > > > > > There's that new CONFIG_SHRINKER_DEBUG too. > > > > > > Which looks like yet another "people add Kconfig options incorrectly". > > > > > > We don't make new features "default y" unless there's some truly > > > pressing reason for it (ie "99.9% of all people will want this" or "we > > > used to always compile this in, now it's optional"). > > > > Hi Linus! > > > > It actually was 'default n' in one of the earlier version of the patchset > > and has been switched to 'default y' based on the following feedback from > > Dave Chinner (https://lore.kernel.org/lkml/YmiWK56bOHyrr64u@rh/): > > > > No. The argument that "if we turn it off there's no overhead" means > > one of two things: > > > > 1. nobody turns it on and it never gets tested and so bitrots and is > > useless, or > > 2. distro's all turn it on because some tool they ship or customer > > they ship to wants it. > > > > Either way, hiding it behind a config option is not an acceptible > > solution for mering poorly thought out infrastructure. > > > > Personally I think that the feature is not that useful for the majority > > of users (this is why default was n), but it's not adding much of the > > overhead, so I had no strong reasons to oppose Dave. > > Cc'ing him just in case. > > > > We should have changelogged these considerations. > > I've asked Joe if checkpatch can get a "default y" detector, to draw > attention to this in the future. Perhaps: --- scripts/checkpatch.pl | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index bf7c5abeefaad..1abec0cd217e6 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -3523,6 +3523,19 @@ sub process { } } +# check new Kconfig entries for default=y +# Only applies when adding the entry originally and if the entry is not +# conditional on anything like default y if <foo> + if ($realfile =~ /Kconfig/ && + !$file && + $line =~ /\+\s*default\s+y\s*$/i) { + if (WARN("KCONFIG_DEFAULT_Y", + "Kconfig entries should generally not be default y\n" . $herecurr) && + $fix) { + $fixed[$fixlinenr] =~ s/default(\s+)y/default${1}n/; + } + } + # check MAINTAINERS entries if ($realfile =~ /^MAINTAINERS$/) { # check MAINTAINERS entries for the right form
