From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 13 Sep 2011 14:52:18 -0700 From: Andrew Morton Subject: Re: [patch v2 2/2] s390: Add architecture code for unmapping crashkernel memory Message-Id: <20110913145218.659f9e21.akpm@google.com> In-Reply-To: <20110913132654.157278466@linux.vnet.ibm.com> References: <20110913132635.063397500@linux.vnet.ibm.com> <20110913132654.157278466@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Michael Holzheu Cc: vgoyal@redhat.com, ebiederm@xmission.com, mahesh@linux.vnet.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, Andrew Morton List-ID: On Tue, 13 Sep 2011 15:26:37 +0200 Michael Holzheu wrote: > From: Michael Holzheu > > This patch implements the crash_map_pages() function for s390. > KEXEC_CRASH_MEM_ALIGN is set to HPAGE_SIZE, in order to support > kernel mappings that use large pages. > > Signed-off-by: Michael Holzheu > --- > arch/s390/include/asm/kexec.h | 3 +++ > arch/s390/kernel/machine_kexec.c | 31 +++++++++++++++++++++++++++++++ > arch/s390/kernel/setup.c | 10 ++++++---- > 3 files changed, 40 insertions(+), 4 deletions(-) > > --- a/arch/s390/include/asm/kexec.h > +++ b/arch/s390/include/asm/kexec.h > @@ -36,6 +36,9 @@ > /* Allocate one page for the pdp and the second for the code */ > #define KEXEC_CONTROL_PAGE_SIZE 4096 > > +/* Alignment of crashkernel memory */ > +#define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE Why not make this unconditional, for all architectures which support hugepages? ie: #ifdef HPAGE_SIZE #define KEXEC_CRASH_MEM_ALIGN HPAGE_SIZE #else #define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE #endif in include/linux/kexec.h? IOW, what are the compromises here? Also, does s390 support CONFIG_HUGETLB_PAGE=n? If so, does the use of HPAGE_SIZE still make sense? Does it compile? > /* The native architecture */ > #define KEXEC_ARCH KEXEC_ARCH_S390 > > --- a/arch/s390/kernel/machine_kexec.c > +++ b/arch/s390/kernel/machine_kexec.c > @@ -243,6 +243,37 @@ static void __machine_kdump(void *image) > #endif > > /* > + * Map or unmap crashkernel memory > + */ > +static void crash_map_pages(int enable) > +{ > + unsigned long size = crashk_res.end - crashk_res.start + 1; resource_size(). > + BUG_ON(crashk_res.start % KEXEC_CRASH_MEM_ALIGN || > + size % KEXEC_CRASH_MEM_ALIGN); > + if (enable) > + vmem_add_mapping(crashk_res.start, size); > + else > + vmem_remove_mapping(crashk_res.start, size); > +} > > ... >