From mboxrd@z Thu Jan 1 00:00:00 1970 From: Claudio Imbrenda Subject: [RFC v1 2/2] VS1544 KSM s390-specific memory comparison functions Date: Mon, 25 Sep 2017 10:46:14 +0200 Message-ID: <1506329174-19265-3-git-send-email-imbrenda@linux.vnet.ibm.com> References: <1506329174-19265-1-git-send-email-imbrenda@linux.vnet.ibm.com> Return-path: In-Reply-To: <1506329174-19265-1-git-send-email-imbrenda@linux.vnet.ibm.com> Sender: kvm-owner@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: borntraeger@de.ibm.com, kvm@vger.kernel.org, linux-mm@kvack.org, nefelim4ag@gmail.com, akpm@linux-foundation.org, aarcange@redhat.com, mingo@kernel.org, zhongjiang@huawei.com, kirill.shutemov@linux.intel.com, arvind.yadav.cs@gmail.com, solee@os.korea.ac.kr, ak@linux.intel.com List-Id: linux-mm.kvack.org Introduce s390 specific page comparison and checksumming functions: The s390-specific functions use the CKSM instruction to quickly calculate the checksum of a page. This provides a measurable reduction on CPU load when KSM is active. Signed-off-by: Claudio Imbrenda --- arch/s390/include/asm/Kbuild | 1 - arch/s390/include/asm/page_memops.h | 18 ++++++++++++++++++ 2 files changed, 18 insertions(+), 1 deletion(-) create mode 100644 arch/s390/include/asm/page_memops.h diff --git a/arch/s390/include/asm/Kbuild b/arch/s390/include/asm/Kbuild index e68b429..b3c8847 100644 --- a/arch/s390/include/asm/Kbuild +++ b/arch/s390/include/asm/Kbuild @@ -14,7 +14,6 @@ generic-y += local.h generic-y += local64.h generic-y += mcs_spinlock.h generic-y += mm-arch-hooks.h -generic-y += page_memops.h generic-y += preempt.h generic-y += trace_clock.h generic-y += word-at-a-time.h diff --git a/arch/s390/include/asm/page_memops.h b/arch/s390/include/asm/page_memops.h new file mode 100644 index 0000000..48b829b --- /dev/null +++ b/arch/s390/include/asm/page_memops.h @@ -0,0 +1,18 @@ +#ifndef _ASM_S390_PAGE_MEMOPS_H +#define _ASM_S390_PAGE_MEMOPS_H + +#include +#include +#include + +static inline u32 calc_page_checksum(struct page *page) +{ + return csum_partial(page_address(page), PAGE_SIZE, 0); +} + +static inline int memcmp_pages(struct page *page1, struct page *page2) +{ + return memcmp(page_address(page1), page_address(page2), PAGE_SIZE); +} + +#endif -- 2.7.4