[PATCH 0/4] Improve compression workspaces memory management

[David Sterba <dsterba@suse.com>]

Hi,

the compression workspaces are allocated as needed an this could fail if
there's no free memory. Moreover, as we might be flushing data from the
restricted contexts we should try our best not to fail.

This patchset preallocates one workspace for each compression type at module
load time (and tries to get one if that fails later). If any further request
for new workspace fails, there's still that one to make progress. IOW workspace
allocation will not fail at writeback time.

I have tested this by instrumenting the code to limit the number of workspaces
to one and did some stress tests.

David Sterba (4):
  btrfs: rename and document compression workspace members
  btrfs: preallocate compression workspaces
  btrfs: make find_workspace always succeed
  btrfs: make find_workspace warn if there are no workspaces

 fs/btrfs/compression.c | 85 ++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 61 insertions(+), 24 deletions(-)

-- 
2.7.1