From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id D56781A074D for ; Tue, 1 Mar 2016 13:28:13 +1100 (AEDT) Date: Tue, 1 Mar 2016 13:27:41 +1100 From: David Gibson To: Michael Ellerman Cc: paulus@samba.org, benh@kernel.crashing.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [3/4] powerpc/mm: Clean up memory hotplug failure paths Message-ID: <20160301022741.GK5427@voom.redhat.com> References: <1454988763-5580-4-git-send-email-david@gibson.dropbear.id.au> <20160301015907.D4344140BA7@ozlabs.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="4wkndigzIeYF6Hbg" In-Reply-To: <20160301015907.D4344140BA7@ozlabs.org> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --4wkndigzIeYF6Hbg Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Mar 01, 2016 at 12:59:07PM +1100, Michael Ellerman wrote: > On Tue, 2016-09-02 at 03:32:42 UTC, David Gibson wrote: > > This makes a number of cleanups to handling of mapping failures during > > memory hotplug on Power: > > > > For errors creating the linear mapping for the hot-added region: > > * This is now reported with EFAULT which is more appropriate than the > > previous EINVAL (the failure is unlikely to be related to the > > function's parameters) > > * An error in this path now prints a warning message, rather than just > > silently failing to add the extra memory. > > * Previously a failure here could result in the region being partially > > mapped. We now clean up any partial mapping before failing. > > > > For errors creating the vmemmap for the hot-added region: > > * This is now reported with EFAULT instead of causing a BUG() - this > > could happen for external reason (e.g. full hash table) so it's be= tter > > to handle this non-fatally > > * An error message is also printed, so the failure won't be silent > > * As above a failure could cause a partially mapped region, we now > > clean this up. > > > ... > > diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c > > index baa1a23..fbc9448 100644 > > --- a/arch/powerpc/mm/init_64.c > > +++ b/arch/powerpc/mm/init_64.c > > @@ -217,15 +219,20 @@ static void vmemmap_remove_mapping(unsigned long = start, > > } > > #endif > > #else /* CONFIG_PPC_BOOK3E */ > > -static void __meminit vmemmap_create_mapping(unsigned long start, > > - unsigned long page_size, > > - unsigned long phys) > > +static int __meminit vmemmap_create_mapping(unsigned long start, > > + unsigned long page_size, > > + unsigned long phys) > > { > > - int mapped =3D htab_bolt_mapping(start, start + page_size, phys, > > - pgprot_val(PAGE_KERNEL), > > - mmu_vmemmap_psize, > > - mmu_kernel_ssize); > > - BUG_ON(mapped < 0); > > + int rc =3D htab_bolt_mapping(start, start + page_size, phys, > > + pgprot_val(PAGE_KERNEL), > > + mmu_vmemmap_psize, mmu_kernel_ssize); > > + if (rc < 0) { > > + int rc2 =3D htab_remove_mapping(start, start + page_size, > > + mmu_vmemmap_psize, > > + mmu_kernel_ssize); >=20 > This breaks the build when CONFIG_MEMORY_HOTPLUG=3Dn, because > htab_remove_mapping() is not defined. >=20 > The obvious fix of moving htab_remove_mapping() out of CONFIG_MEMORY_HOTP= LUG > works, so I'll do that unless anyone objects. Sounds good, thanks for the catch. --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --4wkndigzIeYF6Hbg Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJW1P4cAAoJEGw4ysog2bOSZAUP/RTLXJY1KwfgLBqdbfNL5IUy fdDi7ObyOv6IN2BPCTTmkkXoB72qaXoVi6GpYej6ZS5i+zME6z3Tpr4Wc6SnK92w 23S9Fs3SuC2w1uLkY+iMzLoiCvWLQjIWSltFTgEeiwumX5u3M/cfGkWRbPnswTa8 +SMmQzQBpLufkciSqUX/LB6cZO1S3L3L/pe21NLq5aNH4Fu73A+tbJcwl1w2F9R8 RUTjL8GO6yzCgmFK1ayyeSn2JcsSPTqcHxZ3bcKUtO6Hp98xThI2phuJoCEMxinE 8qwjSpedCJC7LaTXbDToflnDhQOUIGGpR8V3itTOs9yUkx7RsFZU63i80hcBFUGm 0imTVKWGG73rD/mLGq4oG/GDr8jy3Q2Fhu1DCeWfn/S/azhNMv9IwTsP56S/a555 Sjvahf1tpAQO+4tikzzVujBrexXAIdF3DKysN2uxwww5GvbwgxBArBCVHDJ7dhlm TV/YcqRJjg2qoN5t+AypWEVVWBx0+ZqZbP7zJmIh9SSEbl3vammPLDu+nZ3jczR3 lo1efrgzUviPggZzOucSHUX0wrnovn3hkbl5Ukcq52WtYMQHiCEz7wUUE/lLw3Ti 0Z9WD/tbyhQKVi6v3k6rORGr1OVqBtp1pJlINOHnxm4aFfaazGwNP/OVcaUn0FTF 2pdJOc55RGcO//n38VaQ =PIZB -----END PGP SIGNATURE----- --4wkndigzIeYF6Hbg--