| Message ID | 20190121174220.10583-2-dave@stgolabs.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm: make pinned_vm atomic and simplify users | expand |
On Mon, 21 Jan 2019, Davidlohr Bueso wrote > Taking a sleeping lock to _only_ increment a variable is quite the > overkill, and pretty much all users do this. Furthermore, some drivers > (ie: infiniband and scif) that need pinned semantics can go to quite > some trouble to actually delay via workqueue (un)accounting for pinned > pages when not possible to acquire it. Reviewed-by: Christoph Lameter <cl@linux.com>
On Mon 21-01-19 09:42:15, Davidlohr Bueso wrote: > Taking a sleeping lock to _only_ increment a variable is quite the > overkill, and pretty much all users do this. Furthermore, some drivers > (ie: infiniband and scif) that need pinned semantics can go to quite > some trouble to actually delay via workqueue (un)accounting for pinned > pages when not possible to acquire it. > > By making the counter atomic we no longer need to hold the mmap_sem > and can simply some code around it for pinned_vm users. The counter > is 64-bit such that we need not worry about overflows such as rdma > user input controlled from userspace. > > Signed-off-by: Davidlohr Bueso <dbueso@suse.de> The patch looks good to me. You can add: Reviewed-by: Jan Kara <jack@suse.cz> and I really like the cleanups allowed by this in the drivers :) Honza > --- > drivers/infiniband/core/umem.c | 12 ++++++------ > drivers/infiniband/hw/hfi1/user_pages.c | 6 +++--- > drivers/infiniband/hw/qib/qib_user_pages.c | 4 ++-- > drivers/infiniband/hw/usnic/usnic_uiom.c | 8 ++++---- > drivers/misc/mic/scif/scif_rma.c | 6 +++--- > fs/proc/task_mmu.c | 2 +- > include/linux/mm_types.h | 2 +- > kernel/events/core.c | 8 ++++---- > kernel/fork.c | 2 +- > mm/debug.c | 3 ++- > 10 files changed, 27 insertions(+), 26 deletions(-) > > diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c > index 1efe0a74e06b..678abe1afcba 100644 > --- a/drivers/infiniband/core/umem.c > +++ b/drivers/infiniband/core/umem.c > @@ -166,13 +166,13 @@ struct ib_umem *ib_umem_get(struct ib_udata *udata, unsigned long addr, > lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; > > down_write(&mm->mmap_sem); > - if (check_add_overflow(mm->pinned_vm, npages, &new_pinned) || > - (new_pinned > lock_limit && !capable(CAP_IPC_LOCK))) { > + new_pinned = atomic64_read(&mm->pinned_vm) + npages; > + if (new_pinned > lock_limit && !capable(CAP_IPC_LOCK)) { > up_write(&mm->mmap_sem); > ret = -ENOMEM; > goto out; > } > - mm->pinned_vm = new_pinned; > + atomic64_set(&mm->pinned_vm, new_pinned); > up_write(&mm->mmap_sem); > > cur_base = addr & PAGE_MASK; > @@ -234,7 +234,7 @@ struct ib_umem *ib_umem_get(struct ib_udata *udata, unsigned long addr, > __ib_umem_release(context->device, umem, 0); > vma: > down_write(&mm->mmap_sem); > - mm->pinned_vm -= ib_umem_num_pages(umem); > + atomic64_sub(ib_umem_num_pages(umem), &mm->pinned_vm); > up_write(&mm->mmap_sem); > out: > if (vma_list) > @@ -263,7 +263,7 @@ static void ib_umem_release_defer(struct work_struct *work) > struct ib_umem *umem = container_of(work, struct ib_umem, work); > > down_write(&umem->owning_mm->mmap_sem); > - umem->owning_mm->pinned_vm -= ib_umem_num_pages(umem); > + atomic64_sub(ib_umem_num_pages(umem), &umem->owning_mm->pinned_vm); > up_write(&umem->owning_mm->mmap_sem); > > __ib_umem_release_tail(umem); > @@ -302,7 +302,7 @@ void ib_umem_release(struct ib_umem *umem) > } else { > down_write(&umem->owning_mm->mmap_sem); > } > - umem->owning_mm->pinned_vm -= ib_umem_num_pages(umem); > + atomic64_sub(ib_umem_num_pages(umem), &umem->owning_mm->pinned_vm); > up_write(&umem->owning_mm->mmap_sem); > > __ib_umem_release_tail(umem); > diff --git a/drivers/infiniband/hw/hfi1/user_pages.c b/drivers/infiniband/hw/hfi1/user_pages.c > index e341e6dcc388..40a6e434190f 100644 > --- a/drivers/infiniband/hw/hfi1/user_pages.c > +++ b/drivers/infiniband/hw/hfi1/user_pages.c > @@ -92,7 +92,7 @@ bool hfi1_can_pin_pages(struct hfi1_devdata *dd, struct mm_struct *mm, > size = DIV_ROUND_UP(size, PAGE_SIZE); > > down_read(&mm->mmap_sem); > - pinned = mm->pinned_vm; > + pinned = atomic64_read(&mm->pinned_vm); > up_read(&mm->mmap_sem); > > /* First, check the absolute limit against all pinned pages. */ > @@ -112,7 +112,7 @@ int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t np > return ret; > > down_write(&mm->mmap_sem); > - mm->pinned_vm += ret; > + atomic64_add(ret, &mm->pinned_vm); > up_write(&mm->mmap_sem); > > return ret; > @@ -131,7 +131,7 @@ void hfi1_release_user_pages(struct mm_struct *mm, struct page **p, > > if (mm) { /* during close after signal, mm can be NULL */ > down_write(&mm->mmap_sem); > - mm->pinned_vm -= npages; > + atomic64_sub(npages, &mm->pinned_vm); > up_write(&mm->mmap_sem); > } > } > diff --git a/drivers/infiniband/hw/qib/qib_user_pages.c b/drivers/infiniband/hw/qib/qib_user_pages.c > index 16543d5e80c3..602387bf98e7 100644 > --- a/drivers/infiniband/hw/qib/qib_user_pages.c > +++ b/drivers/infiniband/hw/qib/qib_user_pages.c > @@ -75,7 +75,7 @@ static int __qib_get_user_pages(unsigned long start_page, size_t num_pages, > goto bail_release; > } > > - current->mm->pinned_vm += num_pages; > + atomic64_add(num_pages, ¤t->mm->pinned_vm); > > ret = 0; > goto bail; > @@ -156,7 +156,7 @@ void qib_release_user_pages(struct page **p, size_t num_pages) > __qib_release_user_pages(p, num_pages, 1); > > if (current->mm) { > - current->mm->pinned_vm -= num_pages; > + atomic64_sub(num_pages, ¤t->mm->pinned_vm); > up_write(¤t->mm->mmap_sem); > } > } > diff --git a/drivers/infiniband/hw/usnic/usnic_uiom.c b/drivers/infiniband/hw/usnic/usnic_uiom.c > index ce01a59fccc4..854436a2b437 100644 > --- a/drivers/infiniband/hw/usnic/usnic_uiom.c > +++ b/drivers/infiniband/hw/usnic/usnic_uiom.c > @@ -129,7 +129,7 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable, > uiomr->owning_mm = mm = current->mm; > down_write(&mm->mmap_sem); > > - locked = npages + current->mm->pinned_vm; > + locked = npages + atomic64_read(¤t->mm->pinned_vm); > lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; > > if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) { > @@ -187,7 +187,7 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable, > if (ret < 0) > usnic_uiom_put_pages(chunk_list, 0); > else { > - mm->pinned_vm = locked; > + atomic64_set(&mm->pinned_vm, locked); > mmgrab(uiomr->owning_mm); > } > > @@ -441,7 +441,7 @@ static void usnic_uiom_release_defer(struct work_struct *work) > container_of(work, struct usnic_uiom_reg, work); > > down_write(&uiomr->owning_mm->mmap_sem); > - uiomr->owning_mm->pinned_vm -= usnic_uiom_num_pages(uiomr); > + atomic64_sub(usnic_uiom_num_pages(uiomr), &uiomr->owning_mm->pinned_vm); > up_write(&uiomr->owning_mm->mmap_sem); > > __usnic_uiom_release_tail(uiomr); > @@ -469,7 +469,7 @@ void usnic_uiom_reg_release(struct usnic_uiom_reg *uiomr, > } else { > down_write(&uiomr->owning_mm->mmap_sem); > } > - uiomr->owning_mm->pinned_vm -= usnic_uiom_num_pages(uiomr); > + atomic64_sub(usnic_uiom_num_pages(uiomr), &uiomr->owning_mm->pinned_vm); > up_write(&uiomr->owning_mm->mmap_sem); > > __usnic_uiom_release_tail(uiomr); > diff --git a/drivers/misc/mic/scif/scif_rma.c b/drivers/misc/mic/scif/scif_rma.c > index 749321eb91ae..2448368f181e 100644 > --- a/drivers/misc/mic/scif/scif_rma.c > +++ b/drivers/misc/mic/scif/scif_rma.c > @@ -285,7 +285,7 @@ __scif_dec_pinned_vm_lock(struct mm_struct *mm, > } else { > down_write(&mm->mmap_sem); > } > - mm->pinned_vm -= nr_pages; > + atomic64_sub(nr_pages, &mm->pinned_vm); > up_write(&mm->mmap_sem); > return 0; > } > @@ -299,7 +299,7 @@ static inline int __scif_check_inc_pinned_vm(struct mm_struct *mm, > return 0; > > locked = nr_pages; > - locked += mm->pinned_vm; > + locked += atomic64_read(&mm->pinned_vm); > lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; > if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) { > dev_err(scif_info.mdev.this_device, > @@ -307,7 +307,7 @@ static inline int __scif_check_inc_pinned_vm(struct mm_struct *mm, > locked, lock_limit); > return -ENOMEM; > } > - mm->pinned_vm = locked; > + atomic64_set(&mm->pinned_vm, locked); > return 0; > } > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index 6976e17dba68..640ae8a47c73 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -59,7 +59,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm) > SEQ_PUT_DEC("VmPeak:\t", hiwater_vm); > SEQ_PUT_DEC(" kB\nVmSize:\t", total_vm); > SEQ_PUT_DEC(" kB\nVmLck:\t", mm->locked_vm); > - SEQ_PUT_DEC(" kB\nVmPin:\t", mm->pinned_vm); > + SEQ_PUT_DEC(" kB\nVmPin:\t", atomic64_read(&mm->pinned_vm)); > SEQ_PUT_DEC(" kB\nVmHWM:\t", hiwater_rss); > SEQ_PUT_DEC(" kB\nVmRSS:\t", total_rss); > SEQ_PUT_DEC(" kB\nRssAnon:\t", anon); > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > index 6312b02d65ed..0c8be6f9c92d 100644 > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -404,7 +404,7 @@ struct mm_struct { > > unsigned long total_vm; /* Total pages mapped */ > unsigned long locked_vm; /* Pages that have PG_mlocked set */ > - unsigned long pinned_vm; /* Refcount permanently increased */ > + atomic64_t pinned_vm; /* Refcount permanently increased */ > unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */ > unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */ > unsigned long stack_vm; /* VM_STACK */ > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 3cd13a30f732..8df0b77a4687 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -5459,7 +5459,7 @@ static void perf_mmap_close(struct vm_area_struct *vma) > > /* now it's safe to free the pages */ > atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm); > - vma->vm_mm->pinned_vm -= rb->aux_mmap_locked; > + atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm); > > /* this has to be the last one */ > rb_free_aux(rb); > @@ -5532,7 +5532,7 @@ static void perf_mmap_close(struct vm_area_struct *vma) > */ > > atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm); > - vma->vm_mm->pinned_vm -= mmap_locked; > + atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm); > free_uid(mmap_user); > > out_put: > @@ -5680,7 +5680,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) > > lock_limit = rlimit(RLIMIT_MEMLOCK); > lock_limit >>= PAGE_SHIFT; > - locked = vma->vm_mm->pinned_vm + extra; > + locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra; > > if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() && > !capable(CAP_IPC_LOCK)) { > @@ -5721,7 +5721,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) > unlock: > if (!ret) { > atomic_long_add(user_extra, &user->locked_vm); > - vma->vm_mm->pinned_vm += extra; > + atomic64_add(extra, &vma->vm_mm->pinned_vm); > > atomic_inc(&event->mmap_count); > } else if (rb) { > diff --git a/kernel/fork.c b/kernel/fork.c > index c48e9e244a89..a68de9032ced 100644 > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -981,7 +981,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, > mm_pgtables_bytes_init(mm); > mm->map_count = 0; > mm->locked_vm = 0; > - mm->pinned_vm = 0; > + atomic64_set(&mm->pinned_vm, 0); > memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); > spin_lock_init(&mm->page_table_lock); > spin_lock_init(&mm->arg_lock); > diff --git a/mm/debug.c b/mm/debug.c > index 0abb987dad9b..bcf70e365a77 100644 > --- a/mm/debug.c > +++ b/mm/debug.c > @@ -166,7 +166,8 @@ void dump_mm(const struct mm_struct *mm) > mm_pgtables_bytes(mm), > mm->map_count, > mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm, > - mm->pinned_vm, mm->data_vm, mm->exec_vm, mm->stack_vm, > + atomic64_read(&mm->pinned_vm), > + mm->data_vm, mm->exec_vm, mm->stack_vm, > mm->start_code, mm->end_code, mm->start_data, mm->end_data, > mm->start_brk, mm->brk, mm->start_stack, > mm->arg_start, mm->arg_end, mm->env_start, mm->env_end, > -- > 2.16.4 >
On Mon, Jan 21, 2019 at 09:42:15AM -0800, Davidlohr Bueso wrote: > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index 6976e17dba68..640ae8a47c73 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -59,7 +59,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm) > SEQ_PUT_DEC("VmPeak:\t", hiwater_vm); > SEQ_PUT_DEC(" kB\nVmSize:\t", total_vm); > SEQ_PUT_DEC(" kB\nVmLck:\t", mm->locked_vm); > - SEQ_PUT_DEC(" kB\nVmPin:\t", mm->pinned_vm); > + SEQ_PUT_DEC(" kB\nVmPin:\t", atomic64_read(&mm->pinned_vm)); > SEQ_PUT_DEC(" kB\nVmHWM:\t", hiwater_rss); > SEQ_PUT_DEC(" kB\nVmRSS:\t", total_rss); > SEQ_PUT_DEC(" kB\nRssAnon:\t", anon); This is signed on 64b but printed as unsigned, so if some bug made pinned_vm go negative, it would appear as an obviously wrong, gigantic number. Seems ok. For this patch, you can add Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
On Mon, Jan 21, 2019 at 09:42:15AM -0800, Davidlohr Bueso wrote: > Taking a sleeping lock to _only_ increment a variable is quite the > overkill, and pretty much all users do this. Furthermore, some drivers > (ie: infiniband and scif) that need pinned semantics can go to quite > some trouble to actually delay via workqueue (un)accounting for pinned > pages when not possible to acquire it. > > By making the counter atomic we no longer need to hold the mmap_sem > and can simply some code around it for pinned_vm users. The counter > is 64-bit such that we need not worry about overflows such as rdma > user input controlled from userspace. I see a number of MM people Reviewed-by this so are we good to take this in the RDMA tree now? Regards, Jason
On Wed, 23 Jan 2019 11:33:53 -0700 Jason Gunthorpe <jgg@ziepe.ca> wrote: > On Mon, Jan 21, 2019 at 09:42:15AM -0800, Davidlohr Bueso wrote: > > Taking a sleeping lock to _only_ increment a variable is quite the > > overkill, and pretty much all users do this. Furthermore, some drivers > > (ie: infiniband and scif) that need pinned semantics can go to quite > > some trouble to actually delay via workqueue (un)accounting for pinned > > pages when not possible to acquire it. > > > > By making the counter atomic we no longer need to hold the mmap_sem > > and can simply some code around it for pinned_vm users. The counter > > is 64-bit such that we need not worry about overflows such as rdma > > user input controlled from userspace. > > I see a number of MM people Reviewed-by this so are we good to take > this in the RDMA tree now? Please do.
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c index 1efe0a74e06b..678abe1afcba 100644 --- a/drivers/infiniband/core/umem.c +++ b/drivers/infiniband/core/umem.c @@ -166,13 +166,13 @@ struct ib_umem *ib_umem_get(struct ib_udata *udata, unsigned long addr, lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; down_write(&mm->mmap_sem); - if (check_add_overflow(mm->pinned_vm, npages, &new_pinned) || - (new_pinned > lock_limit && !capable(CAP_IPC_LOCK))) { + new_pinned = atomic64_read(&mm->pinned_vm) + npages; + if (new_pinned > lock_limit && !capable(CAP_IPC_LOCK)) { up_write(&mm->mmap_sem); ret = -ENOMEM; goto out; } - mm->pinned_vm = new_pinned; + atomic64_set(&mm->pinned_vm, new_pinned); up_write(&mm->mmap_sem); cur_base = addr & PAGE_MASK; @@ -234,7 +234,7 @@ struct ib_umem *ib_umem_get(struct ib_udata *udata, unsigned long addr, __ib_umem_release(context->device, umem, 0); vma: down_write(&mm->mmap_sem); - mm->pinned_vm -= ib_umem_num_pages(umem); + atomic64_sub(ib_umem_num_pages(umem), &mm->pinned_vm); up_write(&mm->mmap_sem); out: if (vma_list) @@ -263,7 +263,7 @@ static void ib_umem_release_defer(struct work_struct *work) struct ib_umem *umem = container_of(work, struct ib_umem, work); down_write(&umem->owning_mm->mmap_sem); - umem->owning_mm->pinned_vm -= ib_umem_num_pages(umem); + atomic64_sub(ib_umem_num_pages(umem), &umem->owning_mm->pinned_vm); up_write(&umem->owning_mm->mmap_sem); __ib_umem_release_tail(umem); @@ -302,7 +302,7 @@ void ib_umem_release(struct ib_umem *umem) } else { down_write(&umem->owning_mm->mmap_sem); } - umem->owning_mm->pinned_vm -= ib_umem_num_pages(umem); + atomic64_sub(ib_umem_num_pages(umem), &umem->owning_mm->pinned_vm); up_write(&umem->owning_mm->mmap_sem); __ib_umem_release_tail(umem); diff --git a/drivers/infiniband/hw/hfi1/user_pages.c b/drivers/infiniband/hw/hfi1/user_pages.c index e341e6dcc388..40a6e434190f 100644 --- a/drivers/infiniband/hw/hfi1/user_pages.c +++ b/drivers/infiniband/hw/hfi1/user_pages.c @@ -92,7 +92,7 @@ bool hfi1_can_pin_pages(struct hfi1_devdata *dd, struct mm_struct *mm, size = DIV_ROUND_UP(size, PAGE_SIZE); down_read(&mm->mmap_sem); - pinned = mm->pinned_vm; + pinned = atomic64_read(&mm->pinned_vm); up_read(&mm->mmap_sem); /* First, check the absolute limit against all pinned pages. */ @@ -112,7 +112,7 @@ int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t np return ret; down_write(&mm->mmap_sem); - mm->pinned_vm += ret; + atomic64_add(ret, &mm->pinned_vm); up_write(&mm->mmap_sem); return ret; @@ -131,7 +131,7 @@ void hfi1_release_user_pages(struct mm_struct *mm, struct page **p, if (mm) { /* during close after signal, mm can be NULL */ down_write(&mm->mmap_sem); - mm->pinned_vm -= npages; + atomic64_sub(npages, &mm->pinned_vm); up_write(&mm->mmap_sem); } } diff --git a/drivers/infiniband/hw/qib/qib_user_pages.c b/drivers/infiniband/hw/qib/qib_user_pages.c index 16543d5e80c3..602387bf98e7 100644 --- a/drivers/infiniband/hw/qib/qib_user_pages.c +++ b/drivers/infiniband/hw/qib/qib_user_pages.c @@ -75,7 +75,7 @@ static int __qib_get_user_pages(unsigned long start_page, size_t num_pages, goto bail_release; } - current->mm->pinned_vm += num_pages; + atomic64_add(num_pages, ¤t->mm->pinned_vm); ret = 0; goto bail; @@ -156,7 +156,7 @@ void qib_release_user_pages(struct page **p, size_t num_pages) __qib_release_user_pages(p, num_pages, 1); if (current->mm) { - current->mm->pinned_vm -= num_pages; + atomic64_sub(num_pages, ¤t->mm->pinned_vm); up_write(¤t->mm->mmap_sem); } } diff --git a/drivers/infiniband/hw/usnic/usnic_uiom.c b/drivers/infiniband/hw/usnic/usnic_uiom.c index ce01a59fccc4..854436a2b437 100644 --- a/drivers/infiniband/hw/usnic/usnic_uiom.c +++ b/drivers/infiniband/hw/usnic/usnic_uiom.c @@ -129,7 +129,7 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable, uiomr->owning_mm = mm = current->mm; down_write(&mm->mmap_sem); - locked = npages + current->mm->pinned_vm; + locked = npages + atomic64_read(¤t->mm->pinned_vm); lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) { @@ -187,7 +187,7 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable, if (ret < 0) usnic_uiom_put_pages(chunk_list, 0); else { - mm->pinned_vm = locked; + atomic64_set(&mm->pinned_vm, locked); mmgrab(uiomr->owning_mm); } @@ -441,7 +441,7 @@ static void usnic_uiom_release_defer(struct work_struct *work) container_of(work, struct usnic_uiom_reg, work); down_write(&uiomr->owning_mm->mmap_sem); - uiomr->owning_mm->pinned_vm -= usnic_uiom_num_pages(uiomr); + atomic64_sub(usnic_uiom_num_pages(uiomr), &uiomr->owning_mm->pinned_vm); up_write(&uiomr->owning_mm->mmap_sem); __usnic_uiom_release_tail(uiomr); @@ -469,7 +469,7 @@ void usnic_uiom_reg_release(struct usnic_uiom_reg *uiomr, } else { down_write(&uiomr->owning_mm->mmap_sem); } - uiomr->owning_mm->pinned_vm -= usnic_uiom_num_pages(uiomr); + atomic64_sub(usnic_uiom_num_pages(uiomr), &uiomr->owning_mm->pinned_vm); up_write(&uiomr->owning_mm->mmap_sem); __usnic_uiom_release_tail(uiomr); diff --git a/drivers/misc/mic/scif/scif_rma.c b/drivers/misc/mic/scif/scif_rma.c index 749321eb91ae..2448368f181e 100644 --- a/drivers/misc/mic/scif/scif_rma.c +++ b/drivers/misc/mic/scif/scif_rma.c @@ -285,7 +285,7 @@ __scif_dec_pinned_vm_lock(struct mm_struct *mm, } else { down_write(&mm->mmap_sem); } - mm->pinned_vm -= nr_pages; + atomic64_sub(nr_pages, &mm->pinned_vm); up_write(&mm->mmap_sem); return 0; } @@ -299,7 +299,7 @@ static inline int __scif_check_inc_pinned_vm(struct mm_struct *mm, return 0; locked = nr_pages; - locked += mm->pinned_vm; + locked += atomic64_read(&mm->pinned_vm); lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) { dev_err(scif_info.mdev.this_device, @@ -307,7 +307,7 @@ static inline int __scif_check_inc_pinned_vm(struct mm_struct *mm, locked, lock_limit); return -ENOMEM; } - mm->pinned_vm = locked; + atomic64_set(&mm->pinned_vm, locked); return 0; } diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 6976e17dba68..640ae8a47c73 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -59,7 +59,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm) SEQ_PUT_DEC("VmPeak:\t", hiwater_vm); SEQ_PUT_DEC(" kB\nVmSize:\t", total_vm); SEQ_PUT_DEC(" kB\nVmLck:\t", mm->locked_vm); - SEQ_PUT_DEC(" kB\nVmPin:\t", mm->pinned_vm); + SEQ_PUT_DEC(" kB\nVmPin:\t", atomic64_read(&mm->pinned_vm)); SEQ_PUT_DEC(" kB\nVmHWM:\t", hiwater_rss); SEQ_PUT_DEC(" kB\nVmRSS:\t", total_rss); SEQ_PUT_DEC(" kB\nRssAnon:\t", anon); diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 6312b02d65ed..0c8be6f9c92d 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -404,7 +404,7 @@ struct mm_struct { unsigned long total_vm; /* Total pages mapped */ unsigned long locked_vm; /* Pages that have PG_mlocked set */ - unsigned long pinned_vm; /* Refcount permanently increased */ + atomic64_t pinned_vm; /* Refcount permanently increased */ unsigned long data_vm; /* VM_WRITE & ~VM_SHARED & ~VM_STACK */ unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE & ~VM_STACK */ unsigned long stack_vm; /* VM_STACK */ diff --git a/kernel/events/core.c b/kernel/events/core.c index 3cd13a30f732..8df0b77a4687 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5459,7 +5459,7 @@ static void perf_mmap_close(struct vm_area_struct *vma) /* now it's safe to free the pages */ atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm); - vma->vm_mm->pinned_vm -= rb->aux_mmap_locked; + atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm); /* this has to be the last one */ rb_free_aux(rb); @@ -5532,7 +5532,7 @@ static void perf_mmap_close(struct vm_area_struct *vma) */ atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm); - vma->vm_mm->pinned_vm -= mmap_locked; + atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm); free_uid(mmap_user); out_put: @@ -5680,7 +5680,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) lock_limit = rlimit(RLIMIT_MEMLOCK); lock_limit >>= PAGE_SHIFT; - locked = vma->vm_mm->pinned_vm + extra; + locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra; if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() && !capable(CAP_IPC_LOCK)) { @@ -5721,7 +5721,7 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma) unlock: if (!ret) { atomic_long_add(user_extra, &user->locked_vm); - vma->vm_mm->pinned_vm += extra; + atomic64_add(extra, &vma->vm_mm->pinned_vm); atomic_inc(&event->mmap_count); } else if (rb) { diff --git a/kernel/fork.c b/kernel/fork.c index c48e9e244a89..a68de9032ced 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -981,7 +981,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, mm_pgtables_bytes_init(mm); mm->map_count = 0; mm->locked_vm = 0; - mm->pinned_vm = 0; + atomic64_set(&mm->pinned_vm, 0); memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); spin_lock_init(&mm->page_table_lock); spin_lock_init(&mm->arg_lock); diff --git a/mm/debug.c b/mm/debug.c index 0abb987dad9b..bcf70e365a77 100644 --- a/mm/debug.c +++ b/mm/debug.c @@ -166,7 +166,8 @@ void dump_mm(const struct mm_struct *mm) mm_pgtables_bytes(mm), mm->map_count, mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm, - mm->pinned_vm, mm->data_vm, mm->exec_vm, mm->stack_vm, + atomic64_read(&mm->pinned_vm), + mm->data_vm, mm->exec_vm, mm->stack_vm, mm->start_code, mm->end_code, mm->start_data, mm->end_data, mm->start_brk, mm->brk, mm->start_stack, mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
Taking a sleeping lock to _only_ increment a variable is quite the overkill, and pretty much all users do this. Furthermore, some drivers (ie: infiniband and scif) that need pinned semantics can go to quite some trouble to actually delay via workqueue (un)accounting for pinned pages when not possible to acquire it. By making the counter atomic we no longer need to hold the mmap_sem and can simply some code around it for pinned_vm users. The counter is 64-bit such that we need not worry about overflows such as rdma user input controlled from userspace. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> --- drivers/infiniband/core/umem.c | 12 ++++++------ drivers/infiniband/hw/hfi1/user_pages.c | 6 +++--- drivers/infiniband/hw/qib/qib_user_pages.c | 4 ++-- drivers/infiniband/hw/usnic/usnic_uiom.c | 8 ++++---- drivers/misc/mic/scif/scif_rma.c | 6 +++--- fs/proc/task_mmu.c | 2 +- include/linux/mm_types.h | 2 +- kernel/events/core.c | 8 ++++---- kernel/fork.c | 2 +- mm/debug.c | 3 ++- 10 files changed, 27 insertions(+), 26 deletions(-)