ocfs2: revert iput deferring code in ocfs2_drop_dentry_lock
The following patches are reverted in this patch because these patches caused performance regression in the remote unlink() calls. ea455f8a - ocfs2: Push out dropping of dentry lock to ocfs2_wq f7b1aa69 - ocfs2: Fix deadlock on umount 5fd13189 - ocfs2: Don't oops in ocfs2_kill_sb on a failed mount Previous patches in this series removed the possible deadlocks from downconvert thread so the above patches shouldn't be needed anymore. The regression is caused because these patches delay the iput() in case of dentry unlocks. This also delays the unlocking of the open lockres. The open lockresource is required to test if the inode can be wiped from disk or not. When the deleting node does not get the open lock, it marks it as orphan (even though it is not in use by another node/process) and causes a journal checkpoint. This delays operations following the inode eviction. This also moves the inode to the orphaned inode which further causes more I/O and a lot of unneccessary orphans. The following script can be used to generate the load causing issues: declare -a create declare -a remove declare -a iterations=(1 2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384) unique="`mktemp -u XXXXX`" script="/tmp/idontknow-${unique}.sh" cat <<EOF > "${script}" for n in {1..8}; do mkdir -p test/dir\${n} eval touch test/dir\${n}/foo{1.."\$1"} done EOF chmod 700 "${script}" function fcreate () { exec 2>&1 /usr/bin/time --format=%E "${script}" "$1" } function fremove () { exec 2>&1 /usr/bin/time --format=%E ssh node2 "cd `pwd`; rm -Rf test*" } function fcp () { exec 2>&1 /usr/bin/time --format=%E ssh node3 "cd `pwd`; cp -R test test.new" } echo ------------------------------------------------- echo "| # files | create #s | copy #s | remove #s |" echo ------------------------------------------------- for ((x=0; x < ${#iterations[*]} ; x++)) do create[$x]="`fcreate ${iterations[$x]}`" copy[$x]="`fcp ${iterations[$x]}`" remove[$x]="`fremove`" printf "| %8d | %9s | %9s | %9s |\n" ${iterations[$x]} ${create[$x]} ${copy[$x]} ${remove[$x]} done rm "${script}" echo "------------------------" Signed-off-by: NSrinivas Eeda <srinivas.eeda@oracle.com> Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: NJan Kara <jack@suse.cz> Reviewed-by: NMark Fasheh <mfasheh@suse.de> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Showing
想要评论请 注册 或 登录