From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754630AbbGPIrk (ORCPT ); Thu, 16 Jul 2015 04:47:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38497 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752681AbbGPIrh (ORCPT ); Thu, 16 Jul 2015 04:47:37 -0400 From: Baoquan He To: linux-kernel@vger.kernel.org, ncroxon@redhat.com, dyoung@redhat.com, mhuang@redhat.com Cc: Baoquan He Subject: [RHEL6.8 Patch 01/19] [S390] zero page cache synonyms Date: Thu, 16 Jul 2015 16:46:57 +0800 Message-Id: <1437036437-25408-3-git-send-email-bhe@redhat.com> In-Reply-To: <1437036437-25408-1-git-send-email-bhe@redhat.com> References: <1437036437-25408-1-git-send-email-bhe@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Resolves: bz1097904 https://bugzilla.redhat.com/show_bug.cgi?id=1097904 This is back ported from upstream. commit 238ec4efeee4461d5cff2ed3e5a15a3ab850959b Author: Martin Schwidefsky Date: Mon Oct 25 16:10:07 2010 +0200 [S390] zero page cache synonyms If the zero page is mapped to virtual user space addresses that differ only in bit 2^12 or 2^13 we get L1 cache synonyms which can affect performance. Follow the mips model and use multiple zero pages to avoid the synonyms. Signed-off-by: Martin Schwidefsky Signed-off-by: Baoquan He --- arch/s390/include/asm/pgtable.h | 22 +++++++++++++++--- arch/s390/mm/init.c | 49 +++++++++++++++++++++++++++++++++++++---- 2 files changed, 64 insertions(+), 7 deletions(-) diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index b3d2d66..a66fddf 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -46,11 +46,27 @@ extern void vmem_map_init(void); #define update_mmu_cache(vma, address, pte) do { } while (0) /* - * ZERO_PAGE is a global shared page that is always zero: used + * ZERO_PAGE is a global shared page that is always zero; used * for zero-mapped memory areas etc.. */ -extern char empty_zero_page[PAGE_SIZE]; -#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page)) + +extern unsigned long empty_zero_page; +extern unsigned long zero_page_mask; + +#define ZERO_PAGE(vaddr) \ + (virt_to_page((void *)(empty_zero_page + \ + (((unsigned long)(vaddr)) &zero_page_mask)))) + +#define is_zero_pfn is_zero_pfn +static inline int is_zero_pfn(unsigned long pfn) +{ + extern unsigned long zero_pfn; + unsigned long offset_from_zero_pfn = pfn - zero_pfn; + return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT); +} + +#define my_zero_pfn(addr) page_to_pfn(ZERO_PAGE(addr)) + #endif /* !__ASSEMBLY__ */ /* diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index a745dba2..d498dda 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -41,9 +41,52 @@ DEFINE_PER_CPU(struct mmu_gather, mmu_gathers); pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((__aligned__(PAGE_SIZE))); -char empty_zero_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE))); +unsigned long empty_zero_page, zero_page_mask; EXPORT_SYMBOL(empty_zero_page); +static unsigned long setup_zero_pages(void) +{ + struct cpuid cpu_id; + unsigned int order; + unsigned long size; + struct page *page; + int i; + + get_cpu_id(&cpu_id); + switch (cpu_id.machine) { + case 0x9672: /* g5 */ + case 0x2064: /* z900 */ + case 0x2066: /* z900 */ + case 0x2084: /* z990 */ + case 0x2086: /* z990 */ + case 0x2094: /* z9-109 */ + case 0x2096: /* z9-109 */ + order = 0; + break; + case 0x2097: /* z10 */ + case 0x2098: /* z10 */ + default: + order = 2; + break; + } + + empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order); + if (!empty_zero_page) + panic("Out of memory in setup_zero_pages"); + + page = virt_to_page((void *) empty_zero_page); + split_page(page, order); + for (i = 1 << order; i > 0; i--) { + SetPageReserved(page); + page++; + } + + size = PAGE_SIZE << order; + zero_page_mask = (size - 1) & PAGE_MASK; + + return 1UL << order; +} + /* * paging_init() sets up the page tables */ @@ -96,14 +139,12 @@ void __init mem_init(void) max_mapnr = num_physpages = max_low_pfn; high_memory = (void *) __va(max_low_pfn * PAGE_SIZE); - /* clear the zero-page */ - memset(empty_zero_page, 0, PAGE_SIZE); - /* Setup guest page hinting */ cmma_init(); /* this will put all low memory onto the freelists */ totalram_pages += free_all_bootmem(); + totalram_pages -= setup_zero_pages(); /* Setup zeroed pages. */ reservedpages = 0; -- 2.1.0