Date: Tue, 13 Jan 2015 10:11:22 +0100 From: Lars Engels <lars.engels@0x20.net> To: Allan Jude <allanjude@freebsd.org> Cc: freebsd-hackers@freebsd.org Subject: Re: [PATCH] Display progress during getmemsize() so the kernel doesn't look like it hanged Message-ID: <20150113091122.GK67556@e-new.0x20.net> In-Reply-To: <54B35B36.4040504@freebsd.org> References: <D0D89A8E.129518%rpokala@panasas.com> <54B35B36.4040504@freebsd.org>
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On Mon, Jan 12, 2015 at 12:27:18AM -0500, Allan Jude wrote:
> On 2015-01-12 00:24, Pokala, Ravi wrote:
> > Hi folks,
> >=20
> > Several of us have noticed that there's a long pause at the start of
> > booting the kernel on amd64 systems with large amounts of RAM. During t=
his
> > pause, the kernel is mapping in the memory ranges, but does not emit any
> > progress indicators. Because this can take quite a while, it can look l=
ike
> > the kernel has hung. I filed PR 196650 about this issue; this patch just
> > prints out a dot for every GB that's mapped in. We've been using this
> > patch for years at Panasas, and I'm hoping someone can submit it for me.
> >=20
> > Thanks,
> >=20
> > Ravi
> >=20
> >=20
> > Index: sys/amd64/amd64/machdep.c
> > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> > --- sys/amd64/amd64/machdep.c (revision 276903)
> > +++ sys/amd64/amd64/machdep.c (working copy)
> > @@ -1575,6 +1575,9 @@
> > u_long physmem_start, physmem_tunable, memtest;
> > pt_entry_t *pte;
> > quad_t dcons_addr, dcons_size;
> > + u_int32_t page_counter;
> > + int PAGES_PER_MB =3D ((1024 * 1024) / PAGE_SIZE);
> > + int PAGES_PER_GB =3D (PAGES_PER_MB * 1024);
> > =20
> > bzero(physmap, sizeof(physmap));
> > basemem =3D 0;
> > @@ -1678,6 +1681,8 @@
> > * physmap is in bytes, so when converting to page boundaries,
> > * round up the start address and round down the end address.
> > */
> > + printf("Mapping system memory");
> > + page_counter =3D 0;
> > for (i =3D 0; i <=3D physmap_idx; i +=3D 2) {
> > vm_paddr_t end;
> > =20
> > @@ -1688,6 +1693,14 @@
> > int tmp, page_bad, full;
> > int *ptr =3D (int *)CADDR1;
> > =20
> > + /*
> > + * Print a "." every GB, to show we're making progress
> > + */
> > + page_counter++;
> > + if ((page_counter % PAGES_PER_GB) =3D=3D 0) {
> > + printf(".");
> > + }
> > +
> > full =3D FALSE;
> > /*
> > * block out kernel memory as not available.
> > @@ -1792,6 +1805,9 @@
> > break;
> > }
> > }
> > + printf("\nMapped %d GB + %d MB total\n",
> > + (page_counter / PAGES_PER_GB),
> > + ((page_counter % PAGES_PER_GB) / PAGES_PER_MB));
> > *pte =3D 0;
> > invltlb();
> > =20
> >=20
> >=20
> > _______________________________________________
> > freebsd-hackers@freebsd.org mailing list
> > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
> > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.o=
rg"
> >=20
>=20
> Which version(s) of FreeBSD were you seeing this delay on?
>=20
> I know older versions had it, quite badly.
>=20
> setting hw.memtest.tests=3D0 in /boot/loader.conf makes most of the delay
> go away, and the default on -CURRENT is now 0 instead of 1.
>=20
> IIRC, in 10, it defaults to 1, but is switched to 0 in the case of
> virtual machines, because touching every page of memory ruined memory
> over-commit type features.
>=20
> Is this feature still useful with memtest.tests=3D0?
This feature is useful for everyone who has it set to 1, if they know
about it or not. So it's a very useful feature.
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