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path: root/fs/proc_namespace.c
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2014-07-29namespaces: Use task_lock and not rcu to protect nsproxyEric W. Biederman
The synchronous syncrhonize_rcu in switch_task_namespaces makes setns a sufficiently expensive system call that people have complained. Upon inspect nsproxy no longer needs rcu protection for remote reads. remote reads are rare. So optimize for same process reads and write by switching using rask_lock instead. This yields a simpler to understand lock, and a faster setns system call. In particular this fixes a performance regression observed by Rafael David Tinoco <rafael.tinoco@canonical.com>. This is effectively a revert of Pavel Emelyanov's commit cf7b708c8d1d7a27736771bcf4c457b332b0f818 Make access to task's nsproxy lighter from 2007. The race this originialy fixed no longer exists as do_notify_parent uses task_active_pid_ns(parent) instead of parent->nsproxy. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2014-04-01reduce m_start() cost...Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-01-23fs/proc_namespace.c: simplify testing nsp and nsp->mnt_nsAxel Lin
Trivial cleanup to eliminate a goto. Signed-off-by: Axel Lin <axel.lin@ingics.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-10-24don't bother with vfsmount_lock in mounts_poll()Al Viro
wake_up_interruptible/poll_wait provide sufficient barriers; just use ACCESS_ONCE() to fetch ns->event and that's it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14get rid of magic in proc_namespace.cAl Viro
don't rely on proc_mounts->m being the first field; container_of() is there for purpose. No need to bother with ->private, while we are at it - the same container_of will do nicely. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-05-29brlocks/lglocks: API cleanupsAndi Kleen
lglocks and brlocks are currently generated with some complicated macros in lglock.h. But there's no reason to not just use common utility functions and put all the data into a common data structure. In preparation, this patch changes the API to look more like normal function calls with pointers, not magic macros. The patch is rather large because I move over all users in one go to keep it bisectable. This impacts the VFS somewhat in terms of lines changed. But no actual behaviour change. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-06vfs: switch ->show_options() to struct dentry *Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-06vfs: switch ->show_path() to struct dentry *Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-06vfs: switch ->show_devname() to struct dentry *Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-06vfs: switch ->show_stats to struct dentry *Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03vfs: take /proc/*/mounts and friends to fs/proc_namespace.cAl Viro
rationale: that stuff is far tighter bound to fs/namespace.c than to the guts of procfs proper. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>