Date: Sun, 13 Dec 2020 13:37:15 -0700 From: Alan Somers <asomers@freebsd.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: Warner Losh <imp@bsdimp.com>, Ian Lepore <ian@freebsd.org>, FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: char devices without SI_UNMAPPED? Message-ID: <CAOtMX2jYRkPHpey7JnfvK=2d4i_Qg-LW05M=E9hGVSk2uqXjDQ@mail.gmail.com> In-Reply-To: <X9ZuOB7Q3PmOgvvY@kib.kiev.ua> References: <CAOtMX2hFVjFAnNb9wxRTuRsvVptrUsy5C%2BrQECZW-kpKiBXjXA@mail.gmail.com> <6dd927984d69ef0e95e1e90651bcd8087bc4eec4.camel@freebsd.org> <CANCZdfqyLHhuq7h1w7dWh3HoywByOg2RxrezXGTPn_xfYAsTSw@mail.gmail.com> <CAOtMX2iu4ipzdvTer=BzG0hgOiZE2nFHwkrq20bPPoXQe9qkfA@mail.gmail.com> <X9ZuOB7Q3PmOgvvY@kib.kiev.ua>
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On Sun, Dec 13, 2020 at 12:40 PM Konstantin Belousov <kostikbel@gmail.com> wrote: > On Sun, Dec 13, 2020 at 12:20:49PM -0700, Alan Somers wrote: > > On Sun, Dec 13, 2020 at 11:20 AM Warner Losh <imp@bsdimp.com> wrote: > > > > > > > > > > > On Sun, Dec 13, 2020 at 11:18 AM Ian Lepore <ian@freebsd.org> wrote: > > > > > >> On Sun, 2020-12-13 at 10:27 -0700, alan somers wrote: > > >> > I'm trying to exercise the aio code that handles character devices > > >> > that > > >> > don't set the SI_UNMAPPED flag. But I can't find any. Are there > any > > >> > remaining character devices that don't allow unmapped I/O? > > >> > > > >> > -Alan > > >> > > > >> > > >> I assume you mean disk-like devices? Probably mmcsd, flash/at45d, > > >> flash/mx25l. > > >> > > > > > Hm. I don't have any of those. > > > > > > > > > > There are times that it's disabled administratively as well, but that > may > > > be on a per-I/O basis. > > > vfs.zfs.vol.unmap_enabled: 1 > > > > > > > This one doesn't seem to work. It looks like the only functionality it > > gates these days is DIOCGDELETE. > > > > > > > vfs.unmapped_buf_allowed: 1 > > > > > > > Well, this one works. Thanks for the tip. Unfortunately, it's a > tunable, > > so I can't use it for any kind of automated testing. > > There is enough geoms which do not support unmapped bios, even if only in > some configurations. Recursively grep for G_PF_ACCEPT_UNMAPPED in sys/geom > to see what I mean. > That's different. If a provider clears G_PF_ACCEPT_UNMAPPED, geom will create a transient mapping for any unmapped bios sent to that provider. But the provider still has SI_UNMAPPED set. SI_UNMAPPED is used in so few places, I'm wondering if it still has a purpose at all. Is it obsolete? > > After all, an option for geom_nop should be trivial, to force all bios to > map, instead of inheriting from the lower provider. >
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