diff options
Diffstat (limited to 'include/linux/sched/mm.h')
| -rw-r--r-- | include/linux/sched/mm.h | 298 |
1 files changed, 252 insertions, 46 deletions
diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index d5ece7a9a403..b13474825130 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -8,6 +8,7 @@ #include <linux/mm_types.h> #include <linux/gfp.h> #include <linux/sync_core.h> +#include <linux/sched/coredump.h> /* * Routines for handling mm_structs @@ -28,7 +29,7 @@ extern struct mm_struct *mm_alloc(void); * * Use mmdrop() to release the reference acquired by mmgrab(). * - * See also <Documentation/vm/active_mm.rst> for an in-depth explanation + * See also <Documentation/mm/active_mm.rst> for an in-depth explanation * of &mm_struct.mm_count vs &mm_struct.mm_users. */ static inline void mmgrab(struct mm_struct *mm) @@ -36,6 +37,11 @@ static inline void mmgrab(struct mm_struct *mm) atomic_inc(&mm->mm_count); } +static inline void smp_mb__after_mmgrab(void) +{ + smp_mb__after_atomic(); +} + extern void __mmdrop(struct mm_struct *mm); static inline void mmdrop(struct mm_struct *mm) @@ -49,6 +55,63 @@ static inline void mmdrop(struct mm_struct *mm) __mmdrop(mm); } +#ifdef CONFIG_PREEMPT_RT +/* + * RCU callback for delayed mm drop. Not strictly RCU, but call_rcu() is + * by far the least expensive way to do that. + */ +static inline void __mmdrop_delayed(struct rcu_head *rhp) +{ + struct mm_struct *mm = container_of(rhp, struct mm_struct, delayed_drop); + + __mmdrop(mm); +} + +/* + * Invoked from finish_task_switch(). Delegates the heavy lifting on RT + * kernels via RCU. + */ +static inline void mmdrop_sched(struct mm_struct *mm) +{ + /* Provides a full memory barrier. See mmdrop() */ + if (atomic_dec_and_test(&mm->mm_count)) + call_rcu(&mm->delayed_drop, __mmdrop_delayed); +} +#else +static inline void mmdrop_sched(struct mm_struct *mm) +{ + mmdrop(mm); +} +#endif + +/* Helpers for lazy TLB mm refcounting */ +static inline void mmgrab_lazy_tlb(struct mm_struct *mm) +{ + if (IS_ENABLED(CONFIG_MMU_LAZY_TLB_REFCOUNT)) + mmgrab(mm); +} + +static inline void mmdrop_lazy_tlb(struct mm_struct *mm) +{ + if (IS_ENABLED(CONFIG_MMU_LAZY_TLB_REFCOUNT)) { + mmdrop(mm); + } else { + /* + * mmdrop_lazy_tlb must provide a full memory barrier, see the + * membarrier comment finish_task_switch which relies on this. + */ + smp_mb(); + } +} + +static inline void mmdrop_lazy_tlb_sched(struct mm_struct *mm) +{ + if (IS_ENABLED(CONFIG_MMU_LAZY_TLB_REFCOUNT)) + mmdrop_sched(mm); + else + smp_mb(); /* see mmdrop_lazy_tlb() above */ +} + /** * mmget() - Pin the address space associated with a &struct mm_struct. * @mm: The address space to pin. @@ -62,7 +125,7 @@ static inline void mmdrop(struct mm_struct *mm) * * Use mmput() to release the reference acquired by mmget(). * - * See also <Documentation/vm/active_mm.rst> for an in-depth explanation + * See also <Documentation/mm/active_mm.rst> for an in-depth explanation * of &mm_struct.mm_count vs &mm_struct.mm_users. */ static inline void mmget(struct mm_struct *mm) @@ -106,15 +169,46 @@ static inline void mm_update_next_owner(struct mm_struct *mm) #endif /* CONFIG_MEMCG */ #ifdef CONFIG_MMU +#ifndef arch_get_mmap_end +#define arch_get_mmap_end(addr, len, flags) (TASK_SIZE) +#endif + +#ifndef arch_get_mmap_base +#define arch_get_mmap_base(addr, base) (base) +#endif + extern void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack); -extern unsigned long -arch_get_unmapped_area(struct file *, unsigned long, unsigned long, - unsigned long, unsigned long); -extern unsigned long + +unsigned long +arch_get_unmapped_area(struct file *filp, unsigned long addr, + unsigned long len, unsigned long pgoff, + unsigned long flags, vm_flags_t vm_flags); +unsigned long arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr, + unsigned long len, unsigned long pgoff, + unsigned long flags, vm_flags_t); + +unsigned long mm_get_unmapped_area(struct mm_struct *mm, struct file *filp, + unsigned long addr, unsigned long len, + unsigned long pgoff, unsigned long flags); + +unsigned long mm_get_unmapped_area_vmflags(struct mm_struct *mm, + struct file *filp, + unsigned long addr, + unsigned long len, + unsigned long pgoff, + unsigned long flags, + vm_flags_t vm_flags); + +unsigned long +generic_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, - unsigned long flags); + unsigned long flags, vm_flags_t vm_flags); +unsigned long +generic_get_unmapped_area_topdown(struct file *filp, unsigned long addr, + unsigned long len, unsigned long pgoff, + unsigned long flags, vm_flags_t vm_flags); #else static inline void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack) {} @@ -140,7 +234,8 @@ static inline bool in_vfork(struct task_struct *tsk) * another oom-unkillable task does this it should blame itself. */ rcu_read_lock(); - ret = tsk->vfork_done && tsk->real_parent->mm == tsk->mm; + ret = tsk->vfork_done && + rcu_dereference(tsk->real_parent)->mm == tsk->mm; rcu_read_unlock(); return ret; @@ -150,12 +245,13 @@ static inline bool in_vfork(struct task_struct *tsk) * Applies per-task gfp context to the given allocation flags. * PF_MEMALLOC_NOIO implies GFP_NOIO * PF_MEMALLOC_NOFS implies GFP_NOFS + * PF_MEMALLOC_PIN implies !GFP_MOVABLE */ static inline gfp_t current_gfp_context(gfp_t flags) { unsigned int pflags = READ_ONCE(current->flags); - if (unlikely(pflags & (PF_MEMALLOC_NOIO | PF_MEMALLOC_NOFS))) { + if (unlikely(pflags & (PF_MEMALLOC_NOIO | PF_MEMALLOC_NOFS | PF_MEMALLOC_PIN))) { /* * NOIO implies both NOIO and NOFS and it is a weaker context * so always make sure it makes precedence @@ -164,22 +260,85 @@ static inline gfp_t current_gfp_context(gfp_t flags) flags &= ~(__GFP_IO | __GFP_FS); else if (pflags & PF_MEMALLOC_NOFS) flags &= ~__GFP_FS; + + if (pflags & PF_MEMALLOC_PIN) + flags &= ~__GFP_MOVABLE; } return flags; } #ifdef CONFIG_LOCKDEP -extern void __fs_reclaim_acquire(void); -extern void __fs_reclaim_release(void); +extern void __fs_reclaim_acquire(unsigned long ip); +extern void __fs_reclaim_release(unsigned long ip); extern void fs_reclaim_acquire(gfp_t gfp_mask); extern void fs_reclaim_release(gfp_t gfp_mask); #else -static inline void __fs_reclaim_acquire(void) { } -static inline void __fs_reclaim_release(void) { } +static inline void __fs_reclaim_acquire(unsigned long ip) { } +static inline void __fs_reclaim_release(unsigned long ip) { } static inline void fs_reclaim_acquire(gfp_t gfp_mask) { } static inline void fs_reclaim_release(gfp_t gfp_mask) { } #endif +/* Any memory-allocation retry loop should use + * memalloc_retry_wait(), and pass the flags for the most + * constrained allocation attempt that might have failed. + * This provides useful documentation of where loops are, + * and a central place to fine tune the waiting as the MM + * implementation changes. + */ +static inline void memalloc_retry_wait(gfp_t gfp_flags) +{ + /* We use io_schedule_timeout because waiting for memory + * typically included waiting for dirty pages to be + * written out, which requires IO. + */ + __set_current_state(TASK_UNINTERRUPTIBLE); + gfp_flags = current_gfp_context(gfp_flags); + if (gfpflags_allow_blocking(gfp_flags) && + !(gfp_flags & __GFP_NORETRY)) + /* Probably waited already, no need for much more */ + io_schedule_timeout(1); + else + /* Probably didn't wait, and has now released a lock, + * so now is a good time to wait + */ + io_schedule_timeout(HZ/50); +} + +/** + * might_alloc - Mark possible allocation sites + * @gfp_mask: gfp_t flags that would be used to allocate + * + * Similar to might_sleep() and other annotations, this can be used in functions + * that might allocate, but often don't. Compiles to nothing without + * CONFIG_LOCKDEP. Includes a conditional might_sleep() if @gfp allows blocking. + */ +static inline void might_alloc(gfp_t gfp_mask) +{ + fs_reclaim_acquire(gfp_mask); + fs_reclaim_release(gfp_mask); + + might_sleep_if(gfpflags_allow_blocking(gfp_mask)); +} + +/** + * memalloc_flags_save - Add a PF_* flag to current->flags, save old value + * + * This allows PF_* flags to be conveniently added, irrespective of current + * value, and then the old version restored with memalloc_flags_restore(). + */ +static inline unsigned memalloc_flags_save(unsigned flags) +{ + unsigned oldflags = ~current->flags & flags; + current->flags |= flags; + return oldflags; +} + +static inline void memalloc_flags_restore(unsigned flags) +{ + current->flags &= ~flags; +} + /** * memalloc_noio_save - Marks implicit GFP_NOIO allocation scope. * @@ -189,13 +348,12 @@ static inline void fs_reclaim_release(gfp_t gfp_mask) { } * point of view. Use memalloc_noio_restore to end the scope with flags * returned by this function. * - * This function is safe to be used from any context. + * Context: This function is safe to be used from any context. + * Return: The saved flags to be passed to memalloc_noio_restore. */ static inline unsigned int memalloc_noio_save(void) { - unsigned int flags = current->flags & PF_MEMALLOC_NOIO; - current->flags |= PF_MEMALLOC_NOIO; - return flags; + return memalloc_flags_save(PF_MEMALLOC_NOIO); } /** @@ -208,7 +366,7 @@ static inline unsigned int memalloc_noio_save(void) */ static inline void memalloc_noio_restore(unsigned int flags) { - current->flags = (current->flags & ~PF_MEMALLOC_NOIO) | flags; + memalloc_flags_restore(flags); } /** @@ -220,13 +378,12 @@ static inline void memalloc_noio_restore(unsigned int flags) * point of view. Use memalloc_nofs_restore to end the scope with flags * returned by this function. * - * This function is safe to be used from any context. + * Context: This function is safe to be used from any context. + * Return: The saved flags to be passed to memalloc_nofs_restore. */ static inline unsigned int memalloc_nofs_save(void) { - unsigned int flags = current->flags & PF_MEMALLOC_NOFS; - current->flags |= PF_MEMALLOC_NOFS; - return flags; + return memalloc_flags_save(PF_MEMALLOC_NOFS); } /** @@ -239,44 +396,77 @@ static inline unsigned int memalloc_nofs_save(void) */ static inline void memalloc_nofs_restore(unsigned int flags) { - current->flags = (current->flags & ~PF_MEMALLOC_NOFS) | flags; + memalloc_flags_restore(flags); } +/** + * memalloc_noreclaim_save - Marks implicit __GFP_MEMALLOC scope. + * + * This function marks the beginning of the __GFP_MEMALLOC allocation scope. + * All further allocations will implicitly add the __GFP_MEMALLOC flag, which + * prevents entering reclaim and allows access to all memory reserves. This + * should only be used when the caller guarantees the allocation will allow more + * memory to be freed very shortly, i.e. it needs to allocate some memory in + * the process of freeing memory, and cannot reclaim due to potential recursion. + * + * Users of this scope have to be extremely careful to not deplete the reserves + * completely and implement a throttling mechanism which controls the + * consumption of the reserve based on the amount of freed memory. Usage of a + * pre-allocated pool (e.g. mempool) should be always considered before using + * this scope. + * + * Individual allocations under the scope can opt out using __GFP_NOMEMALLOC + * + * Context: This function should not be used in an interrupt context as that one + * does not give PF_MEMALLOC access to reserves. + * See __gfp_pfmemalloc_flags(). + * Return: The saved flags to be passed to memalloc_noreclaim_restore. + */ static inline unsigned int memalloc_noreclaim_save(void) { - unsigned int flags = current->flags & PF_MEMALLOC; - current->flags |= PF_MEMALLOC; - return flags; + return memalloc_flags_save(PF_MEMALLOC); } +/** + * memalloc_noreclaim_restore - Ends the implicit __GFP_MEMALLOC scope. + * @flags: Flags to restore. + * + * Ends the implicit __GFP_MEMALLOC scope started by memalloc_noreclaim_save + * function. Always make sure that the given flags is the return value from the + * pairing memalloc_noreclaim_save call. + */ static inline void memalloc_noreclaim_restore(unsigned int flags) { - current->flags = (current->flags & ~PF_MEMALLOC) | flags; + memalloc_flags_restore(flags); } -#ifdef CONFIG_CMA -static inline unsigned int memalloc_nocma_save(void) -{ - unsigned int flags = current->flags & PF_MEMALLOC_NOCMA; - - current->flags |= PF_MEMALLOC_NOCMA; - return flags; -} - -static inline void memalloc_nocma_restore(unsigned int flags) -{ - current->flags = (current->flags & ~PF_MEMALLOC_NOCMA) | flags; -} -#else -static inline unsigned int memalloc_nocma_save(void) +/** + * memalloc_pin_save - Marks implicit ~__GFP_MOVABLE scope. + * + * This function marks the beginning of the ~__GFP_MOVABLE allocation scope. + * All further allocations will implicitly remove the __GFP_MOVABLE flag, which + * will constraint the allocations to zones that allow long term pinning, i.e. + * not ZONE_MOVABLE zones. + * + * Return: The saved flags to be passed to memalloc_pin_restore. + */ +static inline unsigned int memalloc_pin_save(void) { - return 0; + return memalloc_flags_save(PF_MEMALLOC_PIN); } -static inline void memalloc_nocma_restore(unsigned int flags) +/** + * memalloc_pin_restore - Ends the implicit ~__GFP_MOVABLE scope. + * @flags: Flags to restore. + * + * Ends the implicit ~__GFP_MOVABLE scope started by memalloc_pin_save function. + * Always make sure that the given flags is the return value from the pairing + * memalloc_pin_save call. + */ +static inline void memalloc_pin_restore(unsigned int flags) { + memalloc_flags_restore(flags); } -#endif #ifdef CONFIG_MEMCG DECLARE_PER_CPU(struct mem_cgroup *, int_active_memcg); @@ -288,6 +478,10 @@ DECLARE_PER_CPU(struct mem_cgroup *, int_active_memcg); * __GFP_ACCOUNT allocations till the end of the scope will be charged to the * given memcg. * + * Please, make sure that caller has a reference to the passed memcg structure, + * so its lifetime is guaranteed to exceed the scope between two + * set_active_memcg() calls. + * * NOTE: This function can nest. Users must save the return value and * reset the previous value after their own charging scope is over. */ @@ -296,7 +490,7 @@ set_active_memcg(struct mem_cgroup *memcg) { struct mem_cgroup *old; - if (in_interrupt()) { + if (!in_task()) { old = this_cpu_read(int_active_memcg); this_cpu_write(int_active_memcg, memcg); } else { @@ -337,6 +531,13 @@ enum { static inline void membarrier_mm_sync_core_before_usermode(struct mm_struct *mm) { + /* + * The atomic_read() below prevents CSE. The following should + * help the compiler generate more efficient code on architectures + * where sync_core_before_usermode() is a no-op. + */ + if (!IS_ENABLED(CONFIG_ARCH_HAS_SYNC_CORE_BEFORE_USERMODE)) + return; if (current->mm != mm) return; if (likely(!(atomic_read(&mm->membarrier_state) & @@ -347,6 +548,8 @@ static inline void membarrier_mm_sync_core_before_usermode(struct mm_struct *mm) extern void membarrier_exec_mmap(struct mm_struct *mm); +extern void membarrier_update_current_mm(struct mm_struct *next_mm); + #else #ifdef CONFIG_ARCH_HAS_MEMBARRIER_CALLBACKS static inline void membarrier_arch_switch_mm(struct mm_struct *prev, @@ -361,6 +564,9 @@ static inline void membarrier_exec_mmap(struct mm_struct *mm) static inline void membarrier_mm_sync_core_before_usermode(struct mm_struct *mm) { } +static inline void membarrier_update_current_mm(struct mm_struct *next_mm) +{ +} #endif #endif /* _LINUX_SCHED_MM_H */ |