Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755804Ab2EHOFu (ORCPT ); Tue, 8 May 2012 10:05:50 -0400 Received: from mga14.intel.com ([143.182.124.37]:2242 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755766Ab2EHOFr (ORCPT ); Tue, 8 May 2012 10:05:47 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="140343507" From: Alex Shi To: mgorman@suse.de, npiggin@gmail.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, arnd@arndb.de, rostedt@goodmis.org, fweisbec@gmail.com Cc: jeremy@goop.org, gregkh@linuxfoundation.org, glommer@redhat.com, riel@redhat.com, luto@mit.edu, alex.shi@intel.com, avi@redhat.com, len.brown@intel.com, dhowells@redhat.com, fenghua.yu@intel.com, borislav.petkov@amd.com, yinghai@kernel.org, ak@linux.intel.com, cpw@sgi.com, steiner@sgi.com, akpm@linux-foundation.org, penberg@kernel.org, hughd@google.com, rientjes@google.com, kosaki.motohiro@jp.fujitsu.com, n-horiguchi@ah.jp.nec.com, paul.gortmaker@windriver.com, trenn@suse.de, tj@kernel.org, oleg@redhat.com, axboe@kernel.dk, a.p.zijlstra@chello.nl, kamezawa.hiroyu@jp.fujitsu.com, viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org Subject: [PATCH v3 3/7] x86/tlb: fall back to flush all when meet a THP large page Date: Tue, 8 May 2012 22:03:06 +0800 Message-Id: <1336485790-30902-4-git-send-email-alex.shi@intel.com> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <1336485790-30902-1-git-send-email-alex.shi@intel.com> References: <1336485790-30902-1-git-send-email-alex.shi@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2548 Lines: 81 We don't need to flush large pages by PAGE_SIZE step, that just waste time. and actually, large page don't need 'invlpg' optimizing according to our macro benchmark. So, just flush whole TLB is enough for them. The following result is tested on a 2CPU * 4cores * 2HT NHM EP machine, with THP 'always' setting. Multi-thread testing, '-t' paramter is thread number: without this patch with this patch ./mprotect -t 1 14ns 13ns ./mprotect -t 2 13ns 13ns ./mprotect -t 4 12ns 11ns ./mprotect -t 8 14ns 10ns ./mprotect -t 16 28ns 28ns ./mprotect -t 32 54ns 52ns ./mprotect -t 128 200ns 200ns Signed-off-by: Alex Shi --- arch/x86/mm/tlb.c | 27 +++++++++++++++++++++++++++ 1 files changed, 27 insertions(+), 0 deletions(-) diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index c4e694d..4f709e6 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -316,12 +316,35 @@ void flush_tlb_mm(struct mm_struct *mm) #define FLUSHALL_BAR 16 +static inline int has_large_page(struct mm_struct *mm, + unsigned long start, unsigned long end) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + unsigned long addr; + for (addr = start; addr <= end; addr += HPAGE_SIZE) { + pgd = pgd_offset(mm, addr); + if (likely(!pgd_none(*pgd))) { + pud = pud_offset(pgd, addr); + if (likely(!pud_none(*pud))) { + pmd = pmd_offset(pud, addr); + if (likely(!pmd_none(*pmd))) + if (pmd_large(*pmd)) + return 1; + } + } + } + return 0; +} + void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned long end) { struct mm_struct *mm; if (!cpu_has_invlpg || vma->vm_flags & VM_HUGETLB) { +flush_all: flush_tlb_mm(vma->vm_mm); return; } @@ -344,6 +367,10 @@ void flush_tlb_range(struct vm_area_struct *vma, if ((end - start)/PAGE_SIZE > act_entries/FLUSHALL_BAR) local_flush_tlb(); else { + if (has_large_page(mm, start, end)) { + preempt_enable(); + goto flush_all; + } for (addr = start; addr <= end; addr += PAGE_SIZE) __flush_tlb_single(addr); -- 1.7.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/