Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753080Ab1BVBxt (ORCPT ); Mon, 21 Feb 2011 20:53:49 -0500 Received: from e8.ny.us.ibm.com ([32.97.182.138]:40634 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753026Ab1BVBxq (ORCPT ); Mon, 21 Feb 2011 20:53:46 -0500 Subject: [PATCH 4/5] teach smaps_pte_range() about THP pmds To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, Michael J Wolf , Andrea Arcangeli , akpm@osdl.org, Dave Hansen , Mel Gorman , Johannes Weiner From: Dave Hansen Date: Mon, 21 Feb 2011 17:53:43 -0800 References: <20110222015338.309727CA@kernel> In-Reply-To: <20110222015338.309727CA@kernel> Message-Id: <20110222015343.41586948@kernel> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2612 Lines: 74 v2 - used mm->page_table_lock to fix up locking bug that Mel pointed out. Also remove Acks since things got changed significantly. This adds code to explicitly detect and handle pmd_trans_huge() pmds. It then passes HPAGE_SIZE units in to the smap_pte_entry() function instead of PAGE_SIZE. This means that using /proc/$pid/smaps now will no longer cause THPs to be broken down in to small pages. Signed-off-by: Dave Hansen --- linux-2.6.git-dave/fs/proc/task_mmu.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) diff -puN fs/proc/task_mmu.c~teach-smaps_pte_range-about-thp-pmds fs/proc/task_mmu.c --- linux-2.6.git/fs/proc/task_mmu.c~teach-smaps_pte_range-about-thp-pmds 2011-02-14 09:59:44.034590716 -0800 +++ linux-2.6.git-dave/fs/proc/task_mmu.c 2011-02-21 15:12:46.144181298 -0800 @@ -1,5 +1,6 @@ #include #include +#include #include #include #include @@ -7,6 +8,7 @@ #include #include #include +#include #include #include @@ -385,8 +387,25 @@ static int smaps_pte_range(pmd_t *pmd, u pte_t *pte; spinlock_t *ptl; - split_huge_page_pmd(walk->mm, pmd); - + spin_lock(&walk->mm->page_table_lock); + if (pmd_trans_huge(*pmd)) { + if (pmd_trans_splitting(*pmd)) { + spin_unlock(&walk->mm->page_table_lock); + wait_split_huge_page(vma->anon_vma, pmd); + } else { + smaps_pte_entry(*(pte_t *)pmd, addr, + HPAGE_PMD_SIZE, walk); + spin_unlock(&walk->mm->page_table_lock); + return 0; + } + } else { + spin_unlock(&walk->mm->page_table_lock); + } + /* + * The mmap_sem held all the way back in m_start() is what + * keeps khugepaged out of here and from collapsing things + * in here. + */ pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); for (; addr != end; pte++, addr += PAGE_SIZE) smaps_pte_entry(*pte, addr, PAGE_SIZE, walk); diff -puN mm/migrate.c~teach-smaps_pte_range-about-thp-pmds mm/migrate.c diff -puN mm/mincore.c~teach-smaps_pte_range-about-thp-pmds mm/mincore.c diff -puN include/linux/mm.h~teach-smaps_pte_range-about-thp-pmds include/linux/mm.h diff -puN mm/mempolicy.c~teach-smaps_pte_range-about-thp-pmds mm/mempolicy.c _ -- 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/