> -----Original Message----- > From: Miklos Szeredi [mailto:miklos@xxxxxxxxxx] > Sent: Tuesday, February 05, 2013 3:12 PM > To: Jarzmik, Robert > Cc: linux-fsdevel@xxxxxxxxxxxxxxx > Subject: Re: fuse, readpage and readahead > .. zip ... > On Wed, Nov 28, 2012 at 5:55 PM, Jarzmik, Robert > > filemap_fault() > > ... > > do_generic_file_read() > > page_cache_async_readahead() > > ondemand_readahead() > > __do_page_cache_readahead() > > read_pages() > > fuse_readpages() > > fuse_request_send() => takes around 500ms > > ...zip... > > My question is : is this the expected behaviour, ie. that read-ahead > > blocks the filemap fault path ? If this was already discussed before, > > could you please give me a link to the discussion ? > > Readahead is asynchronous by default. Synchronous mode may be forced with > "-osync_read". See linux/fs/fuse/file.c:fuse_send_readpages(). OK, I think I understand. You mean that in fuse_send_readpages(), if (fc->async_read) is true, fuse_request_send_background() will be used instead of fuse_request_send(). Therefore I think you assume from the backtrace I showed that (struct fuse_con *)->async_read was false, ie. that the reponse to the initial FUSE_INIT by the sdcard daemon has not set FUSE_ASYNC_READ flag. Thanks for you help. Cheers. -- Robert --------------------------------------------------------------------- Intel Corporation SAS (French simplified joint stock company) Registered headquarters: "Les Montalets"- 2, rue de Paris, 92196 Meudon Cedex, France Registration Number: 302 456 199 R.C.S. NANTERRE Capital: 4,572,000 Euros This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies. ��.n��������+%������w��{.n�����{���)�� jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
