From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx119.postini.com [74.125.245.119]) by kanga.kvack.org (Postfix) with SMTP id 91FBC6B005A for ; Thu, 9 Aug 2012 11:03:24 -0400 (EDT) From: "Kirill A. Shutemov" Subject: [PATCH v2 5/6] mm: make clear_huge_page cache clear only around the fault address Date: Thu, 9 Aug 2012 18:03:02 +0300 Message-Id: <1344524583-1096-6-git-send-email-kirill.shutemov@linux.intel.com> In-Reply-To: <1344524583-1096-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1344524583-1096-1-git-send-email-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Andi Kleen , "Kirill A. Shutemov" , Tim Chen , Alex Shi , Jan Beulich , Robert Richter , Andy Lutomirski , Andrew Morton , Andrea Arcangeli , Johannes Weiner , Hugh Dickins , KAMEZAWA Hiroyuki , Mel Gorman , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mips@linux-mips.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org From: Andi Kleen Clearing a 2MB huge page will typically blow away several levels of CPU caches. To avoid this only cache clear the 4K area around the fault address and use a cache avoiding clears for the rest of the 2MB area. Signed-off-by: Andi Kleen Signed-off-by: Kirill A. Shutemov --- mm/memory.c | 30 +++++++++++++++++++++++++++--- 1 files changed, 27 insertions(+), 3 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index b47199a..e9a75c2 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3969,18 +3969,35 @@ EXPORT_SYMBOL(might_fault); #endif #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) + +#ifndef ARCH_HAS_USER_NOCACHE +#define ARCH_HAS_USER_NOCACHE 0 +#endif + +#if ARCH_HAS_USER_NOCACHE == 0 +#define clear_user_highpage_nocache clear_user_highpage +#endif + static void clear_gigantic_page(struct page *page, unsigned long addr, unsigned int pages_per_huge_page) { int i; struct page *p = page; + unsigned long vaddr; + unsigned long haddr = addr & HPAGE_PMD_MASK; + int target = (addr - haddr) >> PAGE_SHIFT; might_sleep(); + vaddr = haddr; for (i = 0; i < pages_per_huge_page; i++, p = mem_map_next(p, page, i)) { cond_resched(); - clear_user_highpage(p, addr + i * PAGE_SIZE); + vaddr = haddr + i*PAGE_SIZE; + if (!ARCH_HAS_USER_NOCACHE || i == target) + clear_user_highpage(p, vaddr); + else + clear_user_highpage_nocache(p, vaddr); } } void clear_huge_page(struct page *page, @@ -3988,16 +4005,23 @@ void clear_huge_page(struct page *page, { int i; unsigned long haddr = addr & HPAGE_PMD_MASK; + unsigned long vaddr; + int target = (addr - haddr) >> PAGE_SHIFT; if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { - clear_gigantic_page(page, haddr, pages_per_huge_page); + clear_gigantic_page(page, addr, pages_per_huge_page); return; } might_sleep(); + vaddr = haddr; for (i = 0; i < pages_per_huge_page; i++) { cond_resched(); - clear_user_highpage(page + i, haddr + i * PAGE_SIZE); + vaddr = haddr + i*PAGE_SIZE; + if (!ARCH_HAS_USER_NOCACHE || i == target) + clear_user_highpage(page + i, vaddr); + else + clear_user_highpage_nocache(page + i, vaddr); } } -- 1.7.7.6 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org