From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 2CB3E6B0083 for ; Sat, 5 Sep 2009 17:23:04 -0400 (EDT) Date: Sat, 5 Sep 2009 22:22:23 +0100 (BST) From: Hugh Dickins Subject: [PATCH 1/3] ksm: clean up obsolete references Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: Izik Eidus , Andrea Arcangeli , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: A few cleanups, given the munlock fix: the comment on ksm_test_exit() no longer applies, and it can be made private to ksm.c; there's no more reference to mmu_gather or tlb.h, and mmap.c doesn't need ksm.h. Signed-off-by: Hugh Dickins --- include/linux/ksm.h | 20 -------------------- mm/ksm.c | 14 +++++++++++++- mm/mmap.c | 1 - 3 files changed, 13 insertions(+), 22 deletions(-) --- mmotm/include/linux/ksm.h 2009-09-05 14:40:16.000000000 +0100 +++ linux/include/linux/ksm.h 2009-09-05 16:41:55.000000000 +0100 @@ -12,8 +12,6 @@ #include #include -struct mmu_gather; - #ifdef CONFIG_KSM int ksm_madvise(struct vm_area_struct *vma, unsigned long start, unsigned long end, int advice, unsigned long *vm_flags); @@ -27,19 +25,6 @@ static inline int ksm_fork(struct mm_str return 0; } -/* - * For KSM to handle OOM without deadlock when it's breaking COW in a - * likely victim of the OOM killer, exit_mmap() has to serialize with - * ksm_exit() after freeing mm's pages but before freeing its page tables. - * That leaves a window in which KSM might refault pages which have just - * been finally unmapped: guard against that with ksm_test_exit(), and - * use it after getting mmap_sem in ksm.c, to check if mm is exiting. - */ -static inline bool ksm_test_exit(struct mm_struct *mm) -{ - return atomic_read(&mm->mm_users) == 0; -} - static inline void ksm_exit(struct mm_struct *mm) { if (test_bit(MMF_VM_MERGEABLE, &mm->flags)) @@ -78,11 +63,6 @@ static inline int ksm_fork(struct mm_str { return 0; } - -static inline bool ksm_test_exit(struct mm_struct *mm) -{ - return 0; -} static inline void ksm_exit(struct mm_struct *mm) { --- mmotm/mm/ksm.c 2009-09-05 14:40:16.000000000 +0100 +++ linux/mm/ksm.c 2009-09-05 16:41:55.000000000 +0100 @@ -32,7 +32,6 @@ #include #include -#include #include /* @@ -285,6 +284,19 @@ static inline int in_stable_tree(struct } /* + * ksmd, and unmerge_and_remove_all_rmap_items(), must not touch an mm's + * page tables after it has passed through ksm_exit() - which, if necessary, + * takes mmap_sem briefly to serialize against them. ksm_exit() does not set + * a special flag: they can just back out as soon as mm_users goes to zero. + * ksm_test_exit() is used throughout to make this test for exit: in some + * places for correctness, in some places just to avoid unnecessary work. + */ +static inline bool ksm_test_exit(struct mm_struct *mm) +{ + return atomic_read(&mm->mm_users) == 0; +} + +/* * We use break_ksm to break COW on a ksm page: it's a stripped down * * if (get_user_pages(current, mm, addr, 1, 1, 1, &page, NULL) == 1) --- mmotm/mm/mmap.c 2009-09-05 14:40:16.000000000 +0100 +++ linux/mm/mmap.c 2009-09-05 16:41:55.000000000 +0100 @@ -27,7 +27,6 @@ #include #include #include -#include #include #include #include -- 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