diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2017-10-31 19:33:02 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-11-30 08:40:43 +0000 |
| commit | 2bf483c9a402941b5594e5ac8ad3b2b4a335fd34 (patch) | |
| tree | b21568c4849d635ecf59e8fba8e3d5bc1cd5afa7 /drivers/md/dm-core.h | |
| parent | 13e6560075607ff354b48556f306bee925328325 (diff) | |
dm: allocate struct mapped_device with kvzalloc
commit 856eb0916d181da6d043cc33e03f54d5c5bbe54a upstream.
The structure srcu_struct can be very big, its size is proportional to the
value CONFIG_NR_CPUS. The Fedora kernel has CONFIG_NR_CPUS 8192, the field
io_barrier in the struct mapped_device has 84kB in the debugging kernel
and 50kB in the non-debugging kernel. The large size may result in failure
of the function kzalloc_node.
In order to avoid the allocation failure, we use the function
kvzalloc_node, this function falls back to vmalloc if a large contiguous
chunk of memory is not available. This patch also moves the field
io_barrier to the last position of struct mapped_device - the reason is
that on many processor architectures, short memory offsets result in
smaller code than long memory offsets - on x86-64 it reduces code size by
320 bytes.
Note to stable kernel maintainers - the kernels 4.11 and older don't have
the function kvzalloc_node, you can use the function vzalloc_node instead.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/md/dm-core.h')
| -rw-r--r-- | drivers/md/dm-core.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h index 203144762f36..6a14f945783c 100644 --- a/drivers/md/dm-core.h +++ b/drivers/md/dm-core.h @@ -29,7 +29,6 @@ struct dm_kobject_holder { * DM targets must _not_ deference a mapped_device to directly access its members! */ struct mapped_device { - struct srcu_struct io_barrier; struct mutex suspend_lock; /* @@ -127,6 +126,8 @@ struct mapped_device { struct blk_mq_tag_set *tag_set; bool use_blk_mq:1; bool init_tio_pdu:1; + + struct srcu_struct io_barrier; }; void dm_init_md_queue(struct mapped_device *md); |