diff options
| author | David Sterba <dsterba@suse.com> | 2021-06-14 22:22:22 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2021-08-23 13:18:59 +0200 |
| commit | b0ee5e1ec44afda53aaa37f8c41ad00d170506cb (patch) | |
| tree | eece79f4063aef4df0a1d66d1d9927346660efc7 /fs/btrfs/compression.c | |
| parent | 23608d51a3b2a0e1e884eba7b1d1eadefe4aadcc (diff) | |
| download | linux-b0ee5e1ec44afda53aaa37f8c41ad00d170506cb.tar.gz | |
btrfs: drop from __GFP_HIGHMEM all allocations
The highmem flag is used for allocating pages for compression and for raid56 pages. The high memory makes sense on 32bit systems but is not without problems. On 64bit system's it's just another layer of wrappers. The time the pages are allocated for compression or raid56 is relatively short (about a transaction commit), so the pages are not blocked indefinitely. As the number of pages depends on the amount of data being written/read, there's a theoretical problem. A fast device on a 32bit system could use most of the low memory pool, while with the highmem allocation that would not happen. This was possibly the original idea long time ago, but nowadays we optimize for 64bit systems. This patch removes all usage of the __GFP_HIGHMEM flag for page allocation, the kmap/kunmap are still in place and will be removed in followup patches. Remaining is masking out the bit in alloc_extent_state and __lookup_free_space_inode, that can safely stay. Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/compression.c')
| -rw-r--r-- | fs/btrfs/compression.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index 30d82cdf128c..49fdec423092 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -721,8 +721,7 @@ blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, goto fail1; for (pg_index = 0; pg_index < nr_pages; pg_index++) { - cb->compressed_pages[pg_index] = alloc_page(GFP_NOFS | - __GFP_HIGHMEM); + cb->compressed_pages[pg_index] = alloc_page(GFP_NOFS); if (!cb->compressed_pages[pg_index]) { faili = pg_index - 1; ret = BLK_STS_RESOURCE; |