From: Theodore Ts'o Date: Sun, 9 Mar 2014 00:51:16 +0000 (-0500) Subject: jbd2: calculate statistics without holding j_state_lock and j_list_lock X-Git-Tag: v3.15-rc1~91^2~22 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=42cf3452d5f5b0817d27c93e4e7d7eab6e89077d;p=pandora-kernel.git jbd2: calculate statistics without holding j_state_lock and j_list_lock The two hottest locks, and thus the biggest scalability bottlenecks, in the jbd2 layer, are the j_list_lock and j_state_lock. This has inspired some people to do some truly unnatural things[1]. [1] https://www.usenix.org/system/files/conference/fast14/fast14-paper_kang.pdf We don't need to be holding both j_state_lock and j_list_lock while calculating the journal statistics, so move those calculations to the very end of jbd2_journal_commit_transaction. Signed-off-by: "Theodore Ts'o" --- Reading git-diff-tree failed