bug#66288: 29.1; Performance regression using pipe for subprocess

[Dmitry Gutov]

On 05/10/2023 08:50, Eli Zaretskii wrote:
> > Date: Thu, 5 Oct 2023 01:54:43 +0300
> > Cc:gregory@heytings.org,gerd.moellmann@gmail.com,66288@debbugs.gnu.org
> > From: Dmitry Gutov<dmitry@gutov.dev>
> >
> > On 05/10/2023 01:49, Paul Eggert wrote:
> > > > +      fcntl (inchannel, F_SETPIPE_SZ, readmax);
> > > This call can fail if you aren't root and you exceed the system limit in
> > > /proc/sys/fs/pipe-max-size. So I suggest that if this fnctl fails with
> > > EPERM, trying it again after clipping to that limit.
> > Perhaps we'd rather fail loudly, so the user is aware that their
> > customized value cannot be applied.
> Why not silently?  The clip_to_bounds call can already silently change
> the original request anyway.

clip_to_bounds clips to 4294967296 or higher, if I'm not mistaken. And 
my current system-wide limit is 1048576.

I usually like to know when my applied configuration is not used (or 
use-able). Anyway, it's not a hard requirement (not for emacs-29 anyway).