From: Jaegeuk Kim Date: Mon, 29 Apr 2013 07:58:39 +0000 (+0900) Subject: f2fs: modify the number of issued pages to merge IOs X-Git-Tag: v3.10-rc1~45^2~7 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ac5d156c78a68b39955ee9b09498ba93831c77d7;p=pandora-kernel.git f2fs: modify the number of issued pages to merge IOs When testing f2fs on an SSD, I found some 128 page IOs followed by 1 page IO were issued by f2fs_write_node_pages. This means that there were some mishandling flows which degrades performance. Previous f2fs_write_node_pages determines the number of pages to be written, nr_to_write, as follows. 1. The bio_get_nr_vecs returns 129 pages. 2. The bio_alloc makes a room for 128 pages. 3. The initial 128 pages go into one bio. 4. The existing bio is submitted, and a new bio is prepared for the last 1 page. 5. Finally, sync_node_pages submits the last 1 page bio. The problem is from the use of bio_get_nr_vecs, so this patch replace it with max_hw_blocks using queue_max_sectors. Signed-off-by: Jaegeuk Kim --- Reading git-diff-tree failed