On 8/22/23 17:53, Miklos Szeredi via fuse-devel wrote:
On Mon, 21 Aug 2023 at 19:48, Bernd Schubert <bschubert@xxxxxxx> wrote:There were two code paths direct-io writes could take. When daemon/server side did not set FOPEN_DIRECT_IO fuse_cache_write_iter -> direct_write_fallback and with FOPEN_DIRECT_IO being set fuse_direct_write_iter Advantage of fuse_direct_write_iter is that it has optimizations for parallel DIO writes - it might only take a shared inode lock, instead of the exclusive lock. With commits b5a2a3a0b776/80e4f25262f9 the fuse_direct_write_iter path also handles concurrent page IO (dirty flush and page release), just the condition on fc->direct_io_relax had to be removed. Performance wise this basically gives the same improvements as commit 153524053bbb, just O_DIRECT is sufficient, without the need that server side sets FOPEN_DIRECT_IO (it has to set FOPEN_PARALLEL_DIRECT_WRITES), though.Consolidating the various direct IO paths would be really nice. Problem is that fuse_direct_write_iter() lacks some code from generic_file_direct_write() and also completely lacks
I see, seems the page invalidation post direct write is needed as well.
direct_write_fallback(). So more thought needs to go into this. Thanks, Miklos
