Re: [PATCH 8/9] bcache: use kvmalloc

From: Vlastimil Babka
Date: Mon Jan 30 2017 - 11:50:32 EST


On 01/30/2017 10:49 AM, Michal Hocko wrote:
From: Michal Hocko <mhocko@xxxxxxxx>

bcache_device_init uses kmalloc for small requests and vmalloc for those
which are larger than 64 pages. This alone is a strange criterion.
Moreover kmalloc can fallback to vmalloc on the failure. Let's simply
use kvmalloc instead as it knows how to handle the fallback properly

I don't see why separate patch, some of the conversions in 5/9 were quite similar (except comparing with PAGE_SIZE, not 64*PAGE_SIZE), but nevermind.

Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>

Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

---
drivers/md/bcache/super.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 3a19cbc8b230..4cb6b88a1465 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -767,16 +767,12 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
}

n = d->nr_stripes * sizeof(atomic_t);
- d->stripe_sectors_dirty = n < PAGE_SIZE << 6
- ? kzalloc(n, GFP_KERNEL)
- : vzalloc(n);
+ d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL);
if (!d->stripe_sectors_dirty)
return -ENOMEM;

n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
- d->full_dirty_stripes = n < PAGE_SIZE << 6
- ? kzalloc(n, GFP_KERNEL)
- : vzalloc(n);
+ d->full_dirty_stripes = kvzalloc(n, GFP_KERNEL);
if (!d->full_dirty_stripes)
return -ENOMEM;