Core code for mmu notifiers. Signed-off-by: Christoph Lameter Signed-off-by: Andrea Arcangeli --- include/linux/mm_types.h | 8 ++ include/linux/mmu_notifier.h | 152 +++++++++++++++++++++++++++++++++++++++++++ include/linux/page-flags.h | 9 ++ kernel/fork.c | 2 mm/Kconfig | 4 + mm/Makefile | 1 mm/mmap.c | 2 mm/mmu_notifier.c | 91 +++++++++++++++++++++++++ 8 files changed, 269 insertions(+) Index: linux-2.6/include/linux/mm_types.h =================================================================== --- linux-2.6.orig/include/linux/mm_types.h 2008-01-24 20:59:17.000000000 -0800 +++ linux-2.6/include/linux/mm_types.h 2008-01-24 20:59:19.000000000 -0800 @@ -153,6 +153,10 @@ struct vm_area_struct { #endif }; +struct mmu_notifier_head { + struct hlist_head head; +}; + struct mm_struct { struct vm_area_struct * mmap; /* list of VMAs */ struct rb_root mm_rb; @@ -219,6 +223,10 @@ struct mm_struct { /* aio bits */ rwlock_t ioctx_list_lock; struct kioctx *ioctx_list; + +#ifdef CONFIG_MMU_NOTIFIER + struct mmu_notifier_head mmu_notifier; /* MMU notifier list */ +#endif }; #endif /* _LINUX_MM_TYPES_H */ Index: linux-2.6/include/linux/mmu_notifier.h =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-2.6/include/linux/mmu_notifier.h 2008-01-24 20:59:19.000000000 -0800 @@ -0,0 +1,152 @@ +#ifndef _LINUX_MMU_NOTIFIER_H +#define _LINUX_MMU_NOTIFIER_H + +/* + * MMU motifier + * + * Notifier functions for hardware and software that establishes external + * references to pages of a Linux system. The notifier calls ensure that + * the external mappings are removed when the Linux VM removes memory ranges + * or individual pages from a process. + * + * These fall into two classes + * + * 1. mmu_notifier + * + * These are callbacks registered with an mm_struct. If mappings are + * removed from an address space then callbacks are performed. + * Spinlocks must be held in order to the walk reverse maps and the + * notifications are performed while the spinlock is held. + * + * + * 2. mmu_rmap_notifier + * + * Callbacks for subsystems that provide their own rmaps. These + * need to walk their own rmaps for a page. The invalidate_page + * callback is outside of locks so that we are not in a strictly + * atomic context (but we may be in a PF_MEMALLOC context if the + * notifier is called from reclaim code) and are able to sleep. + * Rmap notifiers need an extra page bit and are only available + * on 64 bit platforms. It is up to the subsystem to mark pags + * as PageExternalRmap as needed to trigger the callbacks. Pages + * must be marked dirty if dirty bits are set in the external + * pte. + */ + +#include +#include +#include +#include + +struct mmu_notifier_ops; + +struct mmu_notifier { + struct hlist_node hlist; + const struct mmu_notifier_ops *ops; +}; + +struct mmu_notifier_ops { + void (*release)(struct mmu_notifier *mn, + struct mm_struct *mm); + int (*age_page)(struct mmu_notifier *mn, + struct mm_struct *mm, + unsigned long address); + void (*invalidate_page)(struct mmu_notifier *mn, + struct mm_struct *mm, + unsigned long address); + void (*invalidate_range)(struct mmu_notifier *mn, + struct mm_struct *mm, + unsigned long start, unsigned long end); +}; + +struct mmu_rmap_notifier_ops; + +struct mmu_rmap_notifier { + struct hlist_node hlist; + const struct mmu_rmap_notifier_ops *ops; +}; + +struct mmu_rmap_notifier_ops { + /* + * Called with the page lock held after ptes are modified or removed + * so that a subsystem with its own rmap's can remove remote ptes + * mapping a page. + */ + void (*invalidate_page)(struct mmu_rmap_notifier *mrn, struct page *page); +}; + +#ifdef CONFIG_MMU_NOTIFIER + +extern void mmu_notifier_register(struct mmu_notifier *mn, + struct mm_struct *mm); +extern void mmu_notifier_unregister(struct mmu_notifier *mn, + struct mm_struct *mm); +extern void mmu_notifier_release(struct mm_struct *mm); +extern int mmu_notifier_age_page(struct mm_struct *mm, + unsigned long address); + +static inline void mmu_notifier_head_init(struct mmu_notifier_head *mnh) +{ + INIT_HLIST_HEAD(&mnh->head); +} + +#define mmu_notifier(function, mm, args...) \ + do { \ + struct mmu_notifier *__mn; \ + struct hlist_node *__n; \ + \ + if (unlikely(!hlist_empty(&(mm)->mmu_notifier.head))) { \ + rcu_read_lock(); \ + hlist_for_each_entry_rcu(__mn, __n, \ + &(mm)->mmu_notifier.head, \ + hlist) \ + if (__mn->ops->function) \ + __mn->ops->function(__mn, \ + mm, \ + args); \ + rcu_read_unlock(); \ + } \ + } while (0) + +extern void mmu_rmap_notifier_register(struct mmu_rmap_notifier *mrn); +extern void mmu_rmap_notifier_unregister(struct mmu_rmap_notifier *mrn); + +extern struct hlist_head mmu_rmap_notifier_list; + +#define mmu_rmap_notifier(function, args...) \ + do { \ + struct mmu_rmap_notifier *__mrn; \ + struct hlist_node *__n; \ + \ + rcu_read_lock(); \ + hlist_for_each_entry_rcu(__mrn, __n, &mmu_rmap_notifier_list, \ + hlist) \ + if (__mrn->ops->function) \ + __mrn->ops->function(__mrn, args); \ + rcu_read_unlock(); \ + } while (0); + +#else /* CONFIG_MMU_NOTIFIER */ + +#define mmu_notifier(function, mm, args...) do { } while (0) +#define mmu_rmap_notifier(function, args...) do { } while (0) + +static inline void mmu_notifier_register(struct mmu_notifier *mn, + struct mm_struct *mm) {} +static inline void mmu_notifier_unregister(struct mmu_notifier *mn, + struct mm_struct *mm) {} +static inline void mmu_notifier_release(struct mm_struct *mm) {} +static inline void mmu_notifier_age(struct mm_struct *mm, + unsigned long address) +{ + return 0; +} + +static inline void mmu_notifier_head_init(struct mmu_notifier_head *mmh) {} + +static inline void mmu_rmap_notifier_register(struct mmu_rmap_notifier *mrn) {} +static inline void mmu_rmap_notifier_unregister(struct mmu_rmap_notifier *mrn) {} + +#endif /* CONFIG_MMU_NOTIFIER */ + +#endif /* _LINUX_MMU_NOTIFIER_H */ Index: linux-2.6/include/linux/page-flags.h =================================================================== --- linux-2.6.orig/include/linux/page-flags.h 2008-01-24 20:59:17.000000000 -0800 +++ linux-2.6/include/linux/page-flags.h 2008-01-24 20:59:19.000000000 -0800 @@ -105,6 +105,7 @@ * 64 bit | FIELDS | ?????? FLAGS | * 63 32 0 */ +#define PG_external_rmap 30 /* Page has external rmap */ #define PG_uncached 31 /* Page has been mapped as uncached */ #endif @@ -260,6 +261,14 @@ static inline void __ClearPageTail(struc #define SetPageUncached(page) set_bit(PG_uncached, &(page)->flags) #define ClearPageUncached(page) clear_bit(PG_uncached, &(page)->flags) +#if defined(CONFIG_MMU_NOTIFIER) && defined(CONFIG_64BIT) +#define PageExternalRmap(page) test_bit(PG_external_rmap, &(page)->flags) +#define SetPageExternalRmap(page) set_bit(PG_external_rmap, &(page)->flags) +#define ClearPageExternalRmap(page) clear_bit(PG_external_rmap, &(page)->flags) +#else +#define PageExternalRmap(page) 0 +#endif + struct page; /* forward declaration */ extern void cancel_dirty_page(struct page *page, unsigned int account_size); Index: linux-2.6/mm/Kconfig =================================================================== --- linux-2.6.orig/mm/Kconfig 2008-01-24 20:59:17.000000000 -0800 +++ linux-2.6/mm/Kconfig 2008-01-24 20:59:19.000000000 -0800 @@ -193,3 +193,7 @@ config NR_QUICK config VIRT_TO_BUS def_bool y depends on !ARCH_NO_VIRT_TO_BUS + +config MMU_NOTIFIER + def_bool y + bool "MMU notifier, for paging KVM/RDMA" Index: linux-2.6/mm/Makefile =================================================================== --- linux-2.6.orig/mm/Makefile 2008-01-24 20:59:17.000000000 -0800 +++ linux-2.6/mm/Makefile 2008-01-24 20:59:19.000000000 -0800 @@ -30,4 +30,5 @@ obj-$(CONFIG_FS_XIP) += filemap_xip.o obj-$(CONFIG_MIGRATION) += migrate.o obj-$(CONFIG_SMP) += allocpercpu.o obj-$(CONFIG_QUICKLIST) += quicklist.o +obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o Index: linux-2.6/mm/mmu_notifier.c =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-2.6/mm/mmu_notifier.c 2008-01-24 20:59:19.000000000 -0800 @@ -0,0 +1,91 @@ +/* + * linux/mm/mmu_notifier.c + * + * Copyright (C) 2008 Qumranet, Inc. + * Copyright (C) 2008 SGI + * Christoph Lameter + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + */ + +#include +#include + +void mmu_notifier_release(struct mm_struct *mm) +{ + struct mmu_notifier *mn; + struct hlist_node *n; + + if (unlikely(!hlist_empty(&mm->mmu_notifier.head))) { + rcu_read_lock(); + hlist_for_each_entry_rcu(mn, n, + &mm->mmu_notifier.head, hlist) { + if (mn->ops->release) + mn->ops->release(mn, mm); + hlist_del(&mn->hlist); + } + rcu_read_unlock(); + } +} + +/* + * If no young bitflag is supported by the hardware, ->age_page can + * unmap the address and return 1 or 0 depending if the mapping previously + * existed or not. + */ +int mmu_notifier_age_page(struct mm_struct *mm, unsigned long address) +{ + struct mmu_notifier *mn; + struct hlist_node *n; + int young = 0; + + if (unlikely(!hlist_empty(&mm->mmu_notifier.head))) { + rcu_read_lock(); + hlist_for_each_entry_rcu(mn, n, + &mm->mmu_notifier.head, hlist) { + if (mn->ops->age_page) + young |= mn->ops->age_page(mn, mm, address); + } + rcu_read_unlock(); + } + + return young; +} + +static DEFINE_SPINLOCK(mmu_notifier_list_lock); + +void mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm) +{ + spin_lock(&mmu_notifier_list_lock); + hlist_add_head(&mn->hlist, &mm->mmu_notifier.head); + spin_unlock(&mmu_notifier_list_lock); +} +EXPORT_SYMBOL_GPL(mmu_notifier_register); + +void mmu_notifier_unregister(struct mmu_notifier *mn, struct mm_struct *mm) +{ + spin_lock(&mmu_notifier_list_lock); + hlist_del(&mn->hlist); + spin_unlock(&mmu_notifier_list_lock); +} +EXPORT_SYMBOL_GPL(mmu_notifier_unregister); + +HLIST_HEAD(mmu_rmap_notifier_list); + +void mmu_rmap_notifier_register(struct mmu_rmap_notifier *mrn) +{ + spin_lock(&mmu_notifier_list_lock); + hlist_add_head_rcu(&mrn->hlist, &mmu_rmap_notifier_list); + spin_unlock(&mmu_notifier_list_lock); +} +EXPORT_SYMBOL(mmu_rmap_notifier_register); + +void mmu_rmap_notifier_unregister(struct mmu_rmap_notifier *mrn) +{ + spin_lock(&mmu_notifier_list_lock); + hlist_del_rcu(&mrn->hlist); + spin_unlock(&mmu_notifier_list_lock); +} +EXPORT_SYMBOL(mmu_rmap_notifier_unregister); + Index: linux-2.6/kernel/fork.c =================================================================== --- linux-2.6.orig/kernel/fork.c 2008-01-24 20:59:17.000000000 -0800 +++ linux-2.6/kernel/fork.c 2008-01-24 20:59:19.000000000 -0800 @@ -51,6 +51,7 @@ #include #include #include +#include #include #include @@ -359,6 +360,7 @@ static struct mm_struct * mm_init(struct if (likely(!mm_alloc_pgd(mm))) { mm->def_flags = 0; + mmu_notifier_head_init(&mm->mmu_notifier); return mm; } free_mm(mm); Index: linux-2.6/mm/mmap.c =================================================================== --- linux-2.6.orig/mm/mmap.c 2008-01-24 20:59:17.000000000 -0800 +++ linux-2.6/mm/mmap.c 2008-01-24 20:59:19.000000000 -0800 @@ -26,6 +26,7 @@ #include #include #include +#include #include #include @@ -2043,6 +2044,7 @@ void exit_mmap(struct mm_struct *mm) vm_unacct_memory(nr_accounted); free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); tlb_finish_mmu(tlb, 0, end); + mmu_notifier_release(mm); /* * Walk the list again, actually closing and freeing it, -- -- 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/