On Fri, May 11, 2018 at 05:25:50PM +0100, Filipe Manana wrote:
> On Fri, May 11, 2018 at 4:57 PM, David Sterba <dste...@suse.com> wrote:
> > The dedupe range is 16 MiB, with 4KiB pages and 8 byte pointers, the
> > arrays can be 32KiB large. To avoid allocation failures due to
> > fragmented memory, use the allocation with fallback to vmalloc.
> >
> > Signed-off-by: David Sterba <dste...@suse.com>
> > ---
> >
> > This depends on the patches that remove the 16MiB restriction in the
> > dedupe ioctl, but contextually can be applied to the current code too.
> >
> > https://patchwork.kernel.org/patch/10374941/
> >
> > fs/btrfs/ioctl.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> > index b572e38b4b64..a7f517009cd7 100644
> > --- a/fs/btrfs/ioctl.c
> > +++ b/fs/btrfs/ioctl.c
> > @@ -3178,8 +3178,8 @@ static int btrfs_extent_same(struct inode *src, u64
> > loff, u64 olen,
> > * locking. We use an array for the page pointers. Size of the
> > array is
> > * bounded by len, which is in turn bounded by BTRFS_MAX_DEDUPE_LEN.
> > */
> > - cmp.src_pages = kcalloc(num_pages, sizeof(struct page *),
> > GFP_KERNEL);
> > - cmp.dst_pages = kcalloc(num_pages, sizeof(struct page *),
> > GFP_KERNEL);
> > + cmp.src_pages = kvzalloc(num_pages, sizeof(struct page *),
> > GFP_KERNEL);
> > + cmp.dst_pages = kvzalloc(num_pages, sizeof(struct page *),
> > GFP_KERNEL);
>
> Kvzalloc should take 2 parameters and not 3.
And the right function is kvmalloc_array.
> Also, aren't the corresponding kvfree() calls missing?
Yes, thanks for catching it. The updated version:
From: David Sterba <dste...@suse.com>
Subject: [PATCH] btrfs: use kvzalloc for EXTENT_SAME temporary data
The dedupe range is 16 MiB, with 4KiB pages and 8 byte pointers, the
arrays can be 32KiB large. To avoid allocation failures due to
fragmented memory, use the allocation with fallback to vmalloc.
Signed-off-by: David Sterba <dste...@suse.com>
---
fs/btrfs/ioctl.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index b572e38b4b64..4fcfa05ed960 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3178,12 +3178,13 @@ static int btrfs_extent_same(struct inode *src, u64
loff, u64 olen,
* locking. We use an array for the page pointers. Size of the array is
* bounded by len, which is in turn bounded by BTRFS_MAX_DEDUPE_LEN.
*/
- cmp.src_pages = kcalloc(num_pages, sizeof(struct page *), GFP_KERNEL);
- cmp.dst_pages = kcalloc(num_pages, sizeof(struct page *), GFP_KERNEL);
+ cmp.src_pages = kvmalloc_array(num_pages, sizeof(struct page *),
+ GFP_KERNEL);
+ cmp.dst_pages = kvmalloc_array(num_pages, sizeof(struct page *),
+ GFP_KERNEL);
if (!cmp.src_pages || !cmp.dst_pages) {
- kfree(cmp.src_pages);
- kfree(cmp.dst_pages);
- return -ENOMEM;
+ ret = -ENOMEM;
+ goto out_free;
}
if (same_inode)
@@ -3211,8 +3212,9 @@ static int btrfs_extent_same(struct inode *src, u64 loff,
u64 olen,
else
btrfs_double_inode_unlock(src, dst);
- kfree(cmp.src_pages);
- kfree(cmp.dst_pages);
+out_free:
+ kvfree(cmp.src_pages);
+ kvfree(cmp.dst_pages);
return ret;
}
--
2.16.2
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