mm doesn't support non-blockable __GFP_NOFAIL allocation. Because
__GFP_NOFAIL without direct reclamation may just result in a busy
loop within non-sleepable contexts.
static inline struct page *
__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
struct alloc_context *ac)
{
...
/*
* Make sure that __GFP_NOFAIL request doesn't leak out and make sure
* we always retry
*/
if (gfp_mask & __GFP_NOFAIL) {
/*
* All existing users of the __GFP_NOFAIL are blockable, so warn
* of any new users that actually require GFP_NOWAIT
*/
if (WARN_ON_ONCE_GFP(!can_direct_reclaim, gfp_mask))
goto fail;
...
}
...
fail:
warn_alloc(gfp_mask, ac->nodemask,
"page allocation failure: order:%u", order);
got_pg:
return page;
}
Let's move the memory allocation out of the atomic context and use
the normal sleepable context to get pages.
[RFC]: This has only been compile-tested; I'd prefer if the VDPA maintainers
handles it.
Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
Cc: Jason Wang <jasowang@xxxxxxxxxx>
Cc: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
Cc: "Eugenio Pérez" <eperezma@xxxxxxxxxx>
Cc: Maxime Coquelin <maxime.coquelin@xxxxxxxxxx>
Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
---
drivers/vdpa/vdpa_user/iova_domain.c | 21 ++++++++++++++++-----
drivers/vdpa/vdpa_user/iova_domain.h | 3 ++-
drivers/vdpa/vdpa_user/vduse_dev.c | 13 ++++++++++++-
3 files changed, 30 insertions(+), 7 deletions(-)
diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c
index 791d38d6284c..014809ac2b7c 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.c
+++ b/drivers/vdpa/vdpa_user/iova_domain.c
@@ -283,7 +283,7 @@ int vduse_domain_add_user_bounce_pages(struct vduse_iova_domain *domain,
return ret;
}
-void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain)
+void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain, struct page **pages)
{
struct vduse_bounce_map *map;
unsigned long i, count;
@@ -294,15 +294,16 @@ void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain)
count = domain->bounce_size >> PAGE_SHIFT;
for (i = 0; i < count; i++) {
- struct page *page = NULL;
+ struct page *page = pages[i];
map = &domain->bounce_maps[i];
- if (WARN_ON(!map->bounce_page))
+ if (WARN_ON(!map->bounce_page)) {
+ put_page(page);
continue;
+ }
/* Copy user page to kernel page if it's in use */
if (map->orig_phys != INVALID_PHYS_ADDR) {
- page = alloc_page(GFP_ATOMIC | __GFP_NOFAIL);
memcpy_from_page(page_address(page),
map->bounce_page, 0, PAGE_SIZE);
}
@@ -543,10 +544,19 @@ static int vduse_domain_mmap(struct file *file, struct vm_area_struct *vma)
static int vduse_domain_release(struct inode *inode, struct file *file)
{
struct vduse_iova_domain *domain = file->private_data;
+ struct page **pages = NULL;
+ unsigned long count, i;
+
+ if (domain->user_bounce_pages) {
+ count = domain->bounce_size >> PAGE_SHIFT;
+ pages = kmalloc_array(count, sizeof(*pages), GFP_KERNEL | __GFP_NOFAIL);
+ for (i = 0; i < count; i++)
+ pages[i] = alloc_page(GFP_KERNEL | __GFP_NOFAIL);
+ }
spin_lock(&domain->iotlb_lock);
vduse_iotlb_del_range(domain, 0, ULLONG_MAX);
- vduse_domain_remove_user_bounce_pages(domain);
+ vduse_domain_remove_user_bounce_pages(domain, pages);
vduse_domain_free_kernel_bounce_pages(domain);
spin_unlock(&domain->iotlb_lock);
put_iova_domain(&domain->stream_iovad);
@@ -554,6 +564,7 @@ static int vduse_domain_release(struct inode *inode, struct file *file)
vhost_iotlb_free(domain->iotlb);
vfree(domain->bounce_maps);
kfree(domain);
+ kfree(pages);
return 0;
}
diff --git a/drivers/vdpa/vdpa_user/iova_domain.h b/drivers/vdpa/vdpa_user/iova_domain.h
index f92f22a7267d..db0b793d86db 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.h
+++ b/drivers/vdpa/vdpa_user/iova_domain.h
@@ -74,7 +74,8 @@ void vduse_domain_reset_bounce_map(struct vduse_iova_domain *domain);
int vduse_domain_add_user_bounce_pages(struct vduse_iova_domain *domain,
struct page **pages, int count);
-void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain);
+void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain,
+ struct page **pages);
void vduse_domain_destroy(struct vduse_iova_domain *domain);
diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 7ae99691efdf..df7c1b6f1350 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -1030,6 +1030,8 @@ static int vduse_dev_queue_irq_work(struct vduse_dev *dev,
static int vduse_dev_dereg_umem(struct vduse_dev *dev,
u64 iova, u64 size)
{
+ struct page **pages = NULL;
+ unsigned long count, i;
int ret;
mutex_lock(&dev->mem_lock);
@@ -1044,13 +1046,22 @@ static int vduse_dev_dereg_umem(struct vduse_dev *dev,
if (dev->umem->iova != iova || size != dev->domain->bounce_size)
goto unlock;
- vduse_domain_remove_user_bounce_pages(dev->domain);
+ if (dev->domain->user_bounce_pages) {
+ count = dev->domain->bounce_size >> PAGE_SHIFT;
+ pages = kmalloc_array(count, sizeof(*pages),
+ GFP_KERNEL | __GFP_NOFAIL);
+ for (i = 0; i < count; i++)
+ pages[i] = alloc_page(GFP_KERNEL | __GFP_NOFAIL);
+ }
+
+ vduse_domain_remove_user_bounce_pages(dev->domain, pages);
unpin_user_pages_dirty_lock(dev->umem->pages,
dev->umem->npages, true);
atomic64_sub(dev->umem->npages, &dev->umem->mm->pinned_vm);
mmdrop(dev->umem->mm);
vfree(dev->umem->pages);
kfree(dev->umem);
+ kfree(pages);
dev->umem = NULL;
ret = 0;
unlock:
--
2.34.1
>
> Thanks
>
> >
> >
> > > --
> > > Michal Hocko
> > > SUSE Labs
> >
Thanks
Barry
