On Tue, Jun 06, 2017 at 06:21:17PM +0800, Anand Jain wrote: > On 06/03/17 00:58, David Sterba wrote: > > Christoph pointed out that bio allocations backed by a bioset will never > > fail. > > Looks like this feature comes when __GFP_DIRECT_RECLAIM is > set and we aren't, such as [1]. Any idea why? Looks like I am > missing something ?
bio_alloc_bioset: 406 * When @bs is not NULL, if %__GFP_DIRECT_RECLAIM is set then bio_alloc will 407 * always be able to allocate a bio. This is due to the mempool guarantees. > [1] > ----- > static int submit_extent_page(int op, int op_flags, struct > extent_io_tree *tree, > :: > > bio = btrfs_bio_alloc(bdev, sector, BIO_MAX_PAGES, > GFP_NOFS | __GFP_HIGH); GFP_NOFS contains __GFP_DIRECT_RECLAIM, so what's the problem? __GFP_HIGH allows using the reserves, but should not otherwise change the constraints. And it's use seems unnecessary, as far as I could track in the history. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
