From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933585Ab3GCTAN (ORCPT ); Wed, 3 Jul 2013 15:00:13 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:6261 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933121Ab3GCTAH (ORCPT ); Wed, 3 Jul 2013 15:00:07 -0400 X-Authority-Analysis: v=2.0 cv=Odoa/2vY c=1 sm=0 a=Sro2XwOs0tJUSHxCKfOySw==:17 a=Drc5e87SC40A:10 a=Ciwy3NGCPMMA:10 a=wA3p18IoxX8A:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=MNfxkdJI3hwA:10 a=nrACCIEEAAAA:8 a=20KFwNOVAAAA:8 a=VnNF1IyMAAAA:8 a=WfulkdPnAAAA:8 a=omOdbC7AAAAA:8 a=VwQbUJbxAAAA:8 a=Z4Rwk6OoAAAA:8 a=pIFDgr2qhqgKfBQciQ8A:9 a=jEp0ucaQiEUA:10 a=0kPLrQdw3YYA:10 a=l29vjEC0CZ8A:10 a=jbrJJM5MRmoA:10 a=jeBq3FmKZ4MA:10 a=DiBiMfAEcvgbPAQL:21 a=9_At1m2AYK_ELxKB:21 a=Sro2XwOs0tJUSHxCKfOySw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 67.255.60.225 Message-Id: <20130703184108.274834070@goodmis.org> User-Agent: quilt/0.60-1 Date: Wed, 03 Jul 2013 14:41:07 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Naoya Horiguchi , Rik van Riel , Wanpeng Li , Michal Hocko , Mel Gorman , Andi Kleen , KOSAKI Motohiro , Andrew Morton Subject: [130/141] mm: migration: add migrate_entry_wait_huge() References: <20130703183857.307196999@goodmis.org> Content-Disposition: inline; filename=0130-mm-migration-add-migrate_entry_wait_huge.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.6.11.6 stable review patch. If anyone has any objections, please let me know. ------------------ From: Naoya Horiguchi [ Upstream commit 30dad30922ccc733cfdbfe232090cf674dc374dc ] When we have a page fault for the address which is backed by a hugepage under migration, the kernel can't wait correctly and do busy looping on hugepage fault until the migration finishes. As a result, users who try to kick hugepage migration (via soft offlining, for example) occasionally experience long delay or soft lockup. This is because pte_offset_map_lock() can't get a correct migration entry or a correct page table lock for hugepage. This patch introduces migration_entry_wait_huge() to solve this. Signed-off-by: Naoya Horiguchi Reviewed-by: Rik van Riel Reviewed-by: Wanpeng Li Reviewed-by: Michal Hocko Cc: Mel Gorman Cc: Andi Kleen Cc: KOSAKI Motohiro Cc: [2.6.35+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Steven Rostedt --- include/linux/swapops.h | 3 +++ mm/hugetlb.c | 2 +- mm/migrate.c | 23 ++++++++++++++++++----- 3 files changed, 22 insertions(+), 6 deletions(-) diff --git a/include/linux/swapops.h b/include/linux/swapops.h index 47ead51..c5fd30d 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -137,6 +137,7 @@ static inline void make_migration_entry_read(swp_entry_t *entry) extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, unsigned long address); +extern void migration_entry_wait_huge(struct mm_struct *mm, pte_t *pte); #else #define make_migration_entry(page, write) swp_entry(0, 0) @@ -148,6 +149,8 @@ static inline int is_migration_entry(swp_entry_t swp) static inline void make_migration_entry_read(swp_entry_t *entryp) { } static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, unsigned long address) { } +static inline void migration_entry_wait_huge(struct mm_struct *mm, + pte_t *pte) { } static inline int is_write_migration_entry(swp_entry_t entry) { return 0; diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 0bf06e9..7e5ff99 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2825,7 +2825,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, if (ptep) { entry = huge_ptep_get(ptep); if (unlikely(is_hugetlb_entry_migration(entry))) { - migration_entry_wait(mm, (pmd_t *)ptep, address); + migration_entry_wait_huge(mm, ptep); return 0; } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) return VM_FAULT_HWPOISON_LARGE | diff --git a/mm/migrate.c b/mm/migrate.c index a303524..733aa9f 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -181,15 +181,14 @@ static void remove_migration_ptes(struct page *old, struct page *new) * get to the page and wait until migration is finished. * When we return from this function the fault will be retried. */ -void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, - unsigned long address) +static void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, + spinlock_t *ptl) { - pte_t *ptep, pte; - spinlock_t *ptl; + pte_t pte; swp_entry_t entry; struct page *page; - ptep = pte_offset_map_lock(mm, pmd, address, &ptl); + spin_lock(ptl); pte = *ptep; if (!is_swap_pte(pte)) goto out; @@ -217,6 +216,20 @@ out: pte_unmap_unlock(ptep, ptl); } +void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, + unsigned long address) +{ + spinlock_t *ptl = pte_lockptr(mm, pmd); + pte_t *ptep = pte_offset_map(pmd, address); + __migration_entry_wait(mm, ptep, ptl); +} + +void migration_entry_wait_huge(struct mm_struct *mm, pte_t *pte) +{ + spinlock_t *ptl = &(mm)->page_table_lock; + __migration_entry_wait(mm, pte, ptl); +} + #ifdef CONFIG_BLOCK /* Returns true if all buffers are successfully locked */ static bool buffer_migrate_lock_buffers(struct buffer_head *head, -- 1.7.10.4