| Message ID | 20230216051750.3125598-25-surenb@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Per-VMA locks | expand |
Can we change this to active/inactive? I think there is potential for reusing this functionality to even larger degrees and that name would fit better and would still make sense in this context. ie: vma_mark_active() and vma_mark_inactive() ? * Suren Baghdasaryan <surenb@google.com> [230216 00:18]: > Per-vma locking mechanism will search for VMA under RCU protection and > then after locking it, has to ensure it was not removed from the VMA > tree after we found it. To make this check efficient, introduce a > vma->detached flag to mark VMAs which were removed from the VMA tree. > > Signed-off-by: Suren Baghdasaryan <surenb@google.com> > --- > include/linux/mm.h | 11 +++++++++++ > include/linux/mm_types.h | 3 +++ > mm/mmap.c | 2 ++ > 3 files changed, 16 insertions(+) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index f4f702224ec5..3f98344f829c 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -693,6 +693,14 @@ static inline void vma_assert_write_locked(struct vm_area_struct *vma) > VM_BUG_ON_VMA(vma->vm_lock_seq != READ_ONCE(vma->vm_mm->mm_lock_seq), vma); > } > > +static inline void vma_mark_detached(struct vm_area_struct *vma, bool detached) > +{ > + /* When detaching vma should be write-locked */ > + if (detached) > + vma_assert_write_locked(vma); > + vma->detached = detached; > +} > + > #else /* CONFIG_PER_VMA_LOCK */ > > static inline void vma_init_lock(struct vm_area_struct *vma) {} > @@ -701,6 +709,8 @@ static inline bool vma_start_read(struct vm_area_struct *vma) > static inline void vma_end_read(struct vm_area_struct *vma) {} > static inline void vma_start_write(struct vm_area_struct *vma) {} > static inline void vma_assert_write_locked(struct vm_area_struct *vma) {} > +static inline void vma_mark_detached(struct vm_area_struct *vma, > + bool detached) {} > > #endif /* CONFIG_PER_VMA_LOCK */ > > @@ -712,6 +722,7 @@ static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm) > vma->vm_mm = mm; > vma->vm_ops = &dummy_vm_ops; > INIT_LIST_HEAD(&vma->anon_vma_chain); > + vma_mark_detached(vma, false); > vma_init_lock(vma); > } > > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > index e268723eaf44..939f4f5a1115 100644 > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -511,6 +511,9 @@ struct vm_area_struct { > #ifdef CONFIG_PER_VMA_LOCK > int vm_lock_seq; > struct rw_semaphore lock; > + > + /* Flag to indicate areas detached from the mm->mm_mt tree */ > + bool detached; > #endif > > /* > diff --git a/mm/mmap.c b/mm/mmap.c > index 801608726be8..adf40177e68f 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -593,6 +593,7 @@ static inline void vma_complete(struct vma_prepare *vp, > > if (vp->remove) { > again: > + vma_mark_detached(vp->remove, true); > if (vp->file) { > uprobe_munmap(vp->remove, vp->remove->vm_start, > vp->remove->vm_end); > @@ -2267,6 +2268,7 @@ static inline int munmap_sidetree(struct vm_area_struct *vma, > if (mas_store_gfp(mas_detach, vma, GFP_KERNEL)) > return -ENOMEM; > > + vma_mark_detached(vma, true); > if (vma->vm_flags & VM_LOCKED) > vma->vm_mm->locked_vm -= vma_pages(vma); > > -- > 2.39.1 >
On Thu, Feb 23, 2023 at 12:08 PM Liam R. Howlett <Liam.Howlett@oracle.com> wrote: > > > Can we change this to active/inactive? I think there is potential for > reusing this functionality to even larger degrees and that name would > fit better and would still make sense in this context. > > ie: vma_mark_active() and vma_mark_inactive() ? Those names sound too generic (not obvious what active/inactive means), while detached/isolated I think is more clear and specific. Does not really make a huge difference to me but maybe you can come up with better naming that addresses my concern and meets your usecase? > > * Suren Baghdasaryan <surenb@google.com> [230216 00:18]: > > Per-vma locking mechanism will search for VMA under RCU protection and > > then after locking it, has to ensure it was not removed from the VMA > > tree after we found it. To make this check efficient, introduce a > > vma->detached flag to mark VMAs which were removed from the VMA tree. > > > > Signed-off-by: Suren Baghdasaryan <surenb@google.com> > > --- > > include/linux/mm.h | 11 +++++++++++ > > include/linux/mm_types.h | 3 +++ > > mm/mmap.c | 2 ++ > > 3 files changed, 16 insertions(+) > > > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > index f4f702224ec5..3f98344f829c 100644 > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -693,6 +693,14 @@ static inline void vma_assert_write_locked(struct vm_area_struct *vma) > > VM_BUG_ON_VMA(vma->vm_lock_seq != READ_ONCE(vma->vm_mm->mm_lock_seq), vma); > > } > > > > +static inline void vma_mark_detached(struct vm_area_struct *vma, bool detached) > > +{ > > + /* When detaching vma should be write-locked */ > > + if (detached) > > + vma_assert_write_locked(vma); > > + vma->detached = detached; > > +} > > + > > #else /* CONFIG_PER_VMA_LOCK */ > > > > static inline void vma_init_lock(struct vm_area_struct *vma) {} > > @@ -701,6 +709,8 @@ static inline bool vma_start_read(struct vm_area_struct *vma) > > static inline void vma_end_read(struct vm_area_struct *vma) {} > > static inline void vma_start_write(struct vm_area_struct *vma) {} > > static inline void vma_assert_write_locked(struct vm_area_struct *vma) {} > > +static inline void vma_mark_detached(struct vm_area_struct *vma, > > + bool detached) {} > > > > #endif /* CONFIG_PER_VMA_LOCK */ > > > > @@ -712,6 +722,7 @@ static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm) > > vma->vm_mm = mm; > > vma->vm_ops = &dummy_vm_ops; > > INIT_LIST_HEAD(&vma->anon_vma_chain); > > + vma_mark_detached(vma, false); > > vma_init_lock(vma); > > } > > > > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > > index e268723eaf44..939f4f5a1115 100644 > > --- a/include/linux/mm_types.h > > +++ b/include/linux/mm_types.h > > @@ -511,6 +511,9 @@ struct vm_area_struct { > > #ifdef CONFIG_PER_VMA_LOCK > > int vm_lock_seq; > > struct rw_semaphore lock; > > + > > + /* Flag to indicate areas detached from the mm->mm_mt tree */ > > + bool detached; > > #endif > > > > /* > > diff --git a/mm/mmap.c b/mm/mmap.c > > index 801608726be8..adf40177e68f 100644 > > --- a/mm/mmap.c > > +++ b/mm/mmap.c > > @@ -593,6 +593,7 @@ static inline void vma_complete(struct vma_prepare *vp, > > > > if (vp->remove) { > > again: > > + vma_mark_detached(vp->remove, true); > > if (vp->file) { > > uprobe_munmap(vp->remove, vp->remove->vm_start, > > vp->remove->vm_end); > > @@ -2267,6 +2268,7 @@ static inline int munmap_sidetree(struct vm_area_struct *vma, > > if (mas_store_gfp(mas_detach, vma, GFP_KERNEL)) > > return -ENOMEM; > > > > + vma_mark_detached(vma, true); > > if (vma->vm_flags & VM_LOCKED) > > vma->vm_mm->locked_vm -= vma_pages(vma); > > > > -- > > 2.39.1 > > > > -- > To unsubscribe from this group and stop receiving emails from it, send an email to kernel-team+unsubscribe@android.com. >
diff --git a/include/linux/mm.h b/include/linux/mm.h index f4f702224ec5..3f98344f829c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -693,6 +693,14 @@ static inline void vma_assert_write_locked(struct vm_area_struct *vma) VM_BUG_ON_VMA(vma->vm_lock_seq != READ_ONCE(vma->vm_mm->mm_lock_seq), vma); } +static inline void vma_mark_detached(struct vm_area_struct *vma, bool detached) +{ + /* When detaching vma should be write-locked */ + if (detached) + vma_assert_write_locked(vma); + vma->detached = detached; +} + #else /* CONFIG_PER_VMA_LOCK */ static inline void vma_init_lock(struct vm_area_struct *vma) {} @@ -701,6 +709,8 @@ static inline bool vma_start_read(struct vm_area_struct *vma) static inline void vma_end_read(struct vm_area_struct *vma) {} static inline void vma_start_write(struct vm_area_struct *vma) {} static inline void vma_assert_write_locked(struct vm_area_struct *vma) {} +static inline void vma_mark_detached(struct vm_area_struct *vma, + bool detached) {} #endif /* CONFIG_PER_VMA_LOCK */ @@ -712,6 +722,7 @@ static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm) vma->vm_mm = mm; vma->vm_ops = &dummy_vm_ops; INIT_LIST_HEAD(&vma->anon_vma_chain); + vma_mark_detached(vma, false); vma_init_lock(vma); } diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index e268723eaf44..939f4f5a1115 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -511,6 +511,9 @@ struct vm_area_struct { #ifdef CONFIG_PER_VMA_LOCK int vm_lock_seq; struct rw_semaphore lock; + + /* Flag to indicate areas detached from the mm->mm_mt tree */ + bool detached; #endif /* diff --git a/mm/mmap.c b/mm/mmap.c index 801608726be8..adf40177e68f 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -593,6 +593,7 @@ static inline void vma_complete(struct vma_prepare *vp, if (vp->remove) { again: + vma_mark_detached(vp->remove, true); if (vp->file) { uprobe_munmap(vp->remove, vp->remove->vm_start, vp->remove->vm_end); @@ -2267,6 +2268,7 @@ static inline int munmap_sidetree(struct vm_area_struct *vma, if (mas_store_gfp(mas_detach, vma, GFP_KERNEL)) return -ENOMEM; + vma_mark_detached(vma, true); if (vma->vm_flags & VM_LOCKED) vma->vm_mm->locked_vm -= vma_pages(vma);
Per-vma locking mechanism will search for VMA under RCU protection and then after locking it, has to ensure it was not removed from the VMA tree after we found it. To make this check efficient, introduce a vma->detached flag to mark VMAs which were removed from the VMA tree. Signed-off-by: Suren Baghdasaryan <surenb@google.com> --- include/linux/mm.h | 11 +++++++++++ include/linux/mm_types.h | 3 +++ mm/mmap.c | 2 ++ 3 files changed, 16 insertions(+)