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* cgroups: fix a race between rmdir and remountPaul Menage2008-12-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a cgroup is removed, it's unlinked from its parent's children list, but not actually freed until the last dentry on it is released (at which point cgrp->root->number_of_cgroups is decremented). Currently rebind_subsystems checks for the top cgroup's child list being empty in order to rebind subsystems into or out of a hierarchy - this can result in the set of subsystems bound to a hierarchy being removed-but-not-freed cgroup. The simplest fix for this is to forbid remounts that change the set of subsystems on a hierarchy that has removed-but-not-freed cgroups. This bug can be reproduced via: mkdir /mnt/cg mount -t cgroup -o ns,freezer cgroup /mnt/cg mkdir /mnt/cg/foo sleep 1h < /mnt/cg/foo & rmdir /mnt/cg/foo mount -t cgroup -o remount,ns,devices,freezer cgroup /mnt/cg kill $! Though the above will cause oops in -mm only but not mainline, but the bug can cause memory leak in mainline (and even oops) Signed-off-by: Paul Menage <menage@google.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: fix a serious bug in cgroupstatsLi Zefan2008-11-201-2/+5
| | | | | | | | | | | | | | | | | | | | | Try this, and you'll get oops immediately: # cd Documentation/accounting/ # gcc -o getdelays getdelays.c # mount -t cgroup -o debug xxx /mnt # ./getdelays -C /mnt/tasks Because a normal file's dentry->d_fsdata is a pointer to struct cftype, not struct cgroup. After the patch, it returns EINVAL if we try to get cgroupstats from a normal file. Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: <stable@kernel.org> [2.6.25.x, 2.6.26.x, 2.6.27.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: fix potential deadlock in pre_destroyKAMEZAWA Hiroyuki2008-11-201-5/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As Balbir pointed out, memcg's pre_destroy handler has potential deadlock. It has following lock sequence. cgroup_mutex (cgroup_rmdir) -> pre_destroy -> mem_cgroup_pre_destroy-> force_empty -> cpu_hotplug.lock. (lru_add_drain_all-> schedule_work-> get_online_cpus) But, cpuset has following. cpu_hotplug.lock (call notifier) -> cgroup_mutex. (within notifier) Then, this lock sequence should be fixed. Considering how pre_destroy works, it's not necessary to holding cgroup_mutex() while calling it. As a side effect, we don't have to wait at this mutex while memcg's force_empty works.(it can be long when there are tons of pages.) Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: fix invalid cgrp->dentry before cgroup has been completely removedLi Zefan2008-11-071-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This fixes an oops when reading /proc/sched_debug. A cgroup won't be removed completely until finishing cgroup_diput(), so we shouldn't invalidate cgrp->dentry in cgroup_rmdir(). Otherwise, when a group is being removed while cgroup_path() gets called, we may trigger NULL dereference BUG. The bug can be reproduced: # cat test.sh #!/bin/sh mount -t cgroup -o cpu xxx /mnt for (( ; ; )) { mkdir /mnt/sub rmdir /mnt/sub } # ./test.sh & # cat /proc/sched_debug BUG: unable to handle kernel NULL pointer dereference at 00000038 IP: [<c045a47f>] cgroup_path+0x39/0x90 ... Call Trace: [<c0420344>] ? print_cfs_rq+0x6e/0x75d [<c0421160>] ? sched_debug_show+0x72d/0xc1e ... Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: <stable@kernel.org> [2.6.26.x, 2.6.27.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: remove unused variableStephen Rothwell2008-10-261-1/+1
| | | | | | | | | | | /scratch/sfr/next/kernel/cgroup.c: In function 'cgroup_tasks_start': /scratch/sfr/next/kernel/cgroup.c:2107: warning: unused variable 'i' Introduced in commit cc31edceee04a7b87f2be48f9489ebb72d264844 "cgroups: convert tasks file to use a seq_file with shared pid array". Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: convert tasks file to use a seq_file with shared pid arrayPaul Menage2008-10-201-83/+139
| | | | | | | | | | | | | | | | | | | | Rather than pre-generating the entire text for the "tasks" file each time the file is opened, we instead just generate/update the array of process ids and use a seq_file to report these to userspace. All open file handles on the same "tasks" file can share a pid array, which may be updated any time that no thread is actively reading the array. By sharing the array, the potential for userspace to DoS the system by opening many handles on the same "tasks" file is removed. [Based on a patch by Lai Jiangshan, extended to use seq_file] Signed-off-by: Paul Menage <menage@google.com> Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: fix probable race with put_css_set[_taskexit] and find_css_setLai Jiangshan2008-10-201-23/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | put_css_set_taskexit may be called when find_css_set is called on other cpu. And the race will occur: put_css_set_taskexit side find_css_set side | atomic_dec_and_test(&kref->refcount) | /* kref->refcount = 0 */ | .................................................................... | read_lock(&css_set_lock) | find_existing_css_set | get_css_set | read_unlock(&css_set_lock); .................................................................... __release_css_set | .................................................................... | /* use a released css_set */ | [put_css_set is the same. But in the current code, all put_css_set are put into cgroup mutex critical region as the same as find_css_set.] [akpm@linux-foundation.org: repair comments] [menage@google.com: eliminate race in css_set refcounting] Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memrlimit: cgroup mm owner callback changes to add task infoBalbir Singh2008-10-161-1/+3
| | | | | | | | | | | | | | | | | | | | | This patch adds an additional field to the mm_owner callbacks. This field is required to get to the mm that changed. Hold mmap_sem in write mode before calling the mm_owner_changed callback [hugh@veritas.com: fix mmap_sem deadlock] Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm owner: fix race between swapoff and exitBalbir Singh2008-09-291-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There's a race between mm->owner assignment and swapoff, more easily seen when task slab poisoning is turned on. The condition occurs when try_to_unuse() runs in parallel with an exiting task. A similar race can occur with callers of get_task_mm(), such as /proc/<pid>/<mmstats> or ptrace or page migration. CPU0 CPU1 try_to_unuse looks at mm = task0->mm increments mm->mm_users task 0 exits mm->owner needs to be updated, but no new owner is found (mm_users > 1, but no other task has task->mm = task0->mm) mm_update_next_owner() leaves mmput(mm) decrements mm->mm_users task0 freed dereferencing mm->owner fails The fix is to notify the subsystem via mm_owner_changed callback(), if no new owner is found, by specifying the new task as NULL. Jiri Slaby: mm->owner was set to NULL prior to calling cgroup_mm_owner_callbacks(), but must be set after that, so as not to pass NULL as old owner causing oops. Daisuke Nishimura: mm_update_next_owner() may set mm->owner to NULL, but mem_cgroup_from_task() and its callers need to take account of this situation to avoid oops. Hugh Dickins: Lockdep warning and hang below exec_mmap() when testing these patches. exit_mm() up_reads mmap_sem before calling mm_update_next_owner(), so exec_mmap() now needs to do the same. And with that repositioning, there's now no point in mm_need_new_owner() allowing for NULL mm. Reported-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: uninline cgroup_has_css_refs()Li Zefan2008-07-301-1/+1
| | | | | | | | | | | | | | | | It's not small enough, and has 2 call sites. text data bss dec hex filename 12813 1676 4832 19321 4b79 cgroup.o.orig 12775 1676 4832 19283 4b53 cgroup.o Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: remove duplicate code in allocate_cg_link()Li Zefan2008-07-301-18/+12
| | | | | | | | | | | | | | - just call free_cg_links() in allocate_cg_links() - the list will get initialized in allocate_cg_links(), so don't init it twice Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: fix possible memory leakLi Zefan2008-07-301-2/+5
| | | | | | | | | | | | There's a leak if copy_from_user() returns failure. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] get rid of indirect users of namei.hAl Viro2008-07-271-0/+1
| | | | | | | fs.h needs path.h, not namei.h; nfs_fs.h doesn't need it at all. Several places in the tree needed direct include. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* make cgroup_seqfile_release() staticAdrian Bunk2008-07-261-1/+1
| | | | | | | | | cgroup_seqfile_release() can become static. Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup_clone: use pid of newly created task for new cgroupSerge E. Hallyn2008-07-251-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_clone creates a new cgroup with the pid of the task. This works correctly for unshare, but for clone cgroup_clone is called from copy_namespaces inside copy_process, which happens before the new pid is created. As a result, the new cgroup was created with current's pid. This patch: 1. Moves the call inside copy_process to after the new pid is created 2. Passes the struct pid into ns_cgroup_clone (as it is not yet attached to the task) 3. Passes a name from ns_cgroup_clone() into cgroup_clone() so as to keep cgroup_clone() itself simpler 4. Uses pid_vnr() to get the process id value, so that the pid used to name the new cgroup is always the pid as it would be known to the task which did the cloning or unsharing. I think that is the most intuitive thing to do. This way, task t1 does clone(CLONE_NEWPID) to get t2, which does clone(CLONE_NEWPID) to get t3, then the cgroup for t3 will be named for the pid by which t2 knows t3. (Thanks to Dan Smith for finding the main bug) Changelog: June 11: Incorporate Paul Menage's feedback: don't pass NULL to ns_cgroup_clone from unshare, and reduce patch size by using 'nodename' in cgroup_clone. June 10: Original version [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Serge Hallyn <serge@us.ibm.com> Acked-by: Paul Menage <menage@google.com> Tested-by: Dan Smith <danms@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup files: turn attach_task_by_pid directly into a cgroup write handlerPaul Menage2008-07-251-66/+14
| | | | | | | | | | | | | | | This patch changes attach_task_by_pid() to take a u64 rather than a string; as a result it can be called directly as a control groups write_u64 handler, and cgroup_common_file_write() can be removed. Signed-off-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup files: move notify_on_release file to separate write handlerPaul Menage2008-07-251-8/+13
| | | | | | | | | | | | | | | This patch moves the write handler for the cgroups notify_on_release file into a separate handler. This handler requires no cgroups locking since it relies on atomic bitops for synchronization. Signed-off-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: misc cleanups to write_string patchsetPaul Menage2008-07-251-9/+12
| | | | | | | | | | | | | | | | | | | | | This patch contains cleanups suggested by reviewers for the recent write_string() patchset: - pair cgroup_lock_live_group() with cgroup_unlock() in cgroup.c for clarity, rather than directly unlocking cgroup_mutex. - make the return type of cgroup_lock_live_group() a bool - use a #define'd constant for the local buffer size in read/write functions Signed-off-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup files: move the release_agent file to use typed handlersPaul Menage2008-07-251-68/+57
| | | | | | | | | | | | | | | | | | | Adds cgroup_release_agent_write() and cgroup_release_agent_show() methods to handle writing/reading the path to a cgroup hierarchy's release agent. As a result, cgroup_common_file_read() is now unnecessary. As part of the change, a previously-tolerated race in cgroup_release_agent() is avoided by copying the current release_agent_path prior to calling call_usermode_helper(). Signed-off-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup files: add write_string cgroup control file methodPaul Menage2008-07-251-0/+35
| | | | | | | | | | | | | | | | | | | This patch adds a write_string() method for cgroups control files. The semantics are that a buffer is copied from userspace to kernelspace and the handler function invoked on that buffer. The buffer is guaranteed to be nul-terminated, and no longer than max_write_len (defaulting to 64 bytes if unspecified). Later patches will convert existing raw file write handlers in control group subsystems to use this method. Signed-off-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Acked-by: Balbir Singh <balbir@in.ibm.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: annotate two variables with __read_mostlyLi Zefan2008-07-251-2/+2
| | | | | | | | | | | | | - need_forkexit_callback will be read only after system boot. - use_task_css_set_links will be read only after it's set. And these 2 variables are checked when a new process is forked. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: list_for_each cleanupKOSAKI Motohiro2008-07-251-23/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | -------------------------- while() { list_entry(); ... } -------------------------- is equivalent to following code. -------------------------- list_for_each_entry(){ ... } -------------------------- later can review easily more. this patch is just clean up. it doesn't have any behavor change. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: use read lock to guard find_existing_css_set()Li Zefan2008-07-251-2/+2
| | | | | | | | | | | The function does not modify anything (except the temporary css template), so it's sufficient to hold read lock. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: remove node_ prefix_from ns subsystemCedric Le Goater2008-05-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a slight change in the namespace cgroup subsystem api. The change is that previously when cgroup_clone() was called (currently only from the unshare path in ns_proxy cgroup, you'd get a new group named "node_$pid" whereas now you'll get a group named after just your pid.) The only users who would notice it are those who are using the ns_proxy cgroup subsystem to auto-create cgroups when namespaces are unshared - something of an experimental feature, which I think really needs more complete container/namespace support in order to be useful. I suspect the only users are Cedric and Serge, or maybe a few others on containers@lists.linux-foundation.org. And in fact it would only be noticed by the users who make the assumption about how the name is generated, rather than getting it from the /proc/<pid>/cgroups file for the process in question. Whether the change is actually needed or not I'm fairly agnostic on, but I guess it is more elegant to just use the pid as the new group name rather than adding a fairly arbitrary "node_" prefix on the front. [menage@google.com: provided changelog] Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Cc: "Paul Menage" <menage@google.com> Cc: "Serge E. Hallyn" <serue@us.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: bdi: add separate writeback accounting capabilityMiklos Szeredi2008-04-301-1/+1
| | | | | | | | | | | | | | | | | Add a new BDI capability flag: BDI_CAP_NO_ACCT_WB. If this flag is set, then don't update the per-bdi writeback stats from test_set_page_writeback() and test_clear_page_writeback(). Misc cleanups: - convert bdi_cap_writeback_dirty() and friends to static inline functions - create a flag that includes all three dirty/writeback related flags, since almst all users will want to have them toghether Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: add an owner to the mm_structBalbir Singh2008-04-291-0/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove the mem_cgroup member from mm_struct and instead adds an owner. This approach was suggested by Paul Menage. The advantage of this approach is that, once the mm->owner is known, using the subsystem id, the cgroup can be determined. It also allows several control groups that are virtually grouped by mm_struct, to exist independent of the memory controller i.e., without adding mem_cgroup's for each controller, to mm_struct. A new config option CONFIG_MM_OWNER is added and the memory resource controller selects this config option. This patch also adds cgroup callbacks to notify subsystems when mm->owner changes. The mm_cgroup_changed callback is called with the task_lock() of the new task held and is called just prior to changing the mm->owner. I am indebted to Paul Menage for the several reviews of this patchset and helping me make it lighter and simpler. This patch was tested on a powerpc box, it was compiled with both the MM_OWNER config turned on and off. After the thread group leader exits, it's moved to init_css_state by cgroup_exit(), thus all future charges from runnings threads would be redirected to the init_css_set's subsystem. Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Hugh Dickins <hugh@veritas.com> Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Cc: Hirokazu Takahashi <taka@valinux.co.jp> Cc: David Rientjes <rientjes@google.com>, Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Reviewed-by: Paul Menage <menage@google.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: introduce cft->read_seq()Serge E. Hallyn2008-04-291-6/+9
| | | | | | | | | | | | | | Introduce a read_seq() helper in cftype, which uses seq_file to print out lists. Use it in the devices cgroup. Also split devices.allow into two files, so now devices.deny and devices.allow are the ones to use to manipulate the whitelist, while devices.list outputs the cgroup's current whitelist. Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Acked-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: remove the css_set linked-listLi Zefan2008-04-291-20/+20
| | | | | | | | | | | | | Now we can run through the hash table instead of running through the linked-list. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: simplify init_subsys()Li Zefan2008-04-291-26/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | We are at system boot and there is only 1 cgroup group (i,e, init_css_set), so we don't need to run through the css_set linked list. Neither do we need to run through the task list, since no processes have been created yet. Also referring to a comment in cgroup.h: struct css_set { ... /* * Set of subsystem states, one for each subsystem. This array * is immutable after creation apart from the init_css_set * during subsystem registration (at boot time). */ struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; } Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: use a hash table for css_set findingLi Zefan2008-04-291-12/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we attach a process to a different cgroup, the css_set linked-list will be run through to find a suitable existing css_set to use. This patch implements a hash table for better performance. The following benchmarks have been tested: For N in 1, 5, 10, 50, 100, 500, 1000, create N cgroups with one sleeping task in each, and then move an additional task through each cgroup in turn. Here is a test result: N Loop orig - Time(s) hash - Time(s) ---------------------------------------------- 1 10000 1.201231728 1.196311177 5 2000 1.065743872 1.040566424 10 1000 0.991054735 0.986876440 50 200 0.976554203 0.969608733 100 100 0.998504680 0.969218270 500 20 1.157347764 0.962602963 1000 10 1.619521852 1.085140172 Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: add the trigger callback to struct cftypePavel Emelyanov2008-04-291-0/+4
| | | | | | | | | | | | | | Trigger callback can be used to receive a kick-up from the user space. The string written is ignored. The cftype->private is used for multiplexing events. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Paul Menage <menage@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: switch to proc_create()Li Zefan2008-04-291-4/+1
| | | | | | | | | | There is a race between create_proc_entry() and the assignment of file ops. proc_create() is invented to fix it. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: annotate cgroup_init_subsys with __initLi Zefan2008-04-291-1/+1
| | | | | | | | | | It is called by cgroup_init() and cgroup_init_early() only, which are annotated with __init. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* CGroups _s64 files: add cgroups read_s64/write_s64 file methodsPaul Menage2008-04-291-10/+28
| | | | | | | | | | | | | | | | These patches add cgroups read_s64 and write_s64 control file methods (the signed equivalent of read_u64/write_u64) and use them to implement the cpu.rt_runtime_us control file in the CFS cgroup subsystem. This patch: These are the signed equivalents of the read_u64/write_u64 methods Signed-off-by: Paul Menage <menage@google.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* CGroup API files: move "releasable" to cgroup_debug subsystemPaul Menage2008-04-291-23/+0
| | | | | | | | | | | | | | | | | | | The "releasable" control file provided by the cgroup framework exports the state of a per-cgroup flag that's related to the notify-on-release feature. This isn't really generally useful, unless you're trying to debug this particular feature of cgroups. This patch moves the "releasable" file to the cgroup_debug subsystem. Signed-off-by: Paul Menage <menage@google.com> Cc: "Li Zefan" <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* CGroup API files: add cgroup map data typePaul Menage2008-04-291-1/+52
| | | | | | | | | | | | | | | | | | Adds a new type of supported control file representation, a map from strings to u64 values. Each map entry is printed as a line in a similar format to /proc/vmstat, i.e. "$key $value\n" Signed-off-by: Paul Menage <menage@google.com> Cc: "Li Zefan" <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* CGroup API files: strip all trailing whitespace in cgroup_write_u64Paul Menage2008-04-291-4/+1
| | | | | | | | | | | | | | | This removes the need for people to remember to pass the -n flag to echo when writing values to cgroup control files. Signed-off-by: Paul Menage <menage@google.com> Cc: "Li Zefan" <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* CGroup API files: rename read/write_uint methods to read_write_u64Paul Menage2008-04-291-16/+16
| | | | | | | | | | | | | | | | | | Several people have justifiably complained that the "_uint" suffix is inappropriate for functions that handle u64 values, so this patch just renames all these functions and their users to have the suffic _u64. [peterz@infradead.org: build fix] Signed-off-by: Paul Menage <menage@google.com> Cc: "Li Zefan" <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: fix sparse warning of shadow symbol in cgroup.cPaul Jackson2008-04-291-5/+5
| | | | | | | | | | | | | | | | | | Fix a code warning: symbol 'p' shadows an earlier one This is a reincarnation of Harvey Harrison's patch: cpuset: sparse warnings in cpuset.c Independently, Cliff Wickman moved the affected code, from kernel/cpuset.c to kernel/cgroup.c, in his patch: cpusets: update_cpumask revision Signed-off-by: Paul Jackson <pj@sgi.com> Cc: Harvey Harrison <harvey.harrison@gmail.com> Cc: Cliff Wickman <cpw@sgi.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* make cgroup_enable_task_cg_lists() staticAdrian Bunk2008-04-291-1/+1
| | | | | | | | | | Make the needlessly global cgroup_enable_task_cg_lists() static. Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: fix a race condition in manipulating tsk->cg_listLi Zefan2008-04-181-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When I ran a test program to fork mass processes and at the same time 'cat /cgroup/tasks', I got the following oops: ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:72! invalid opcode: 0000 [#1] SMP Pid: 4178, comm: a.out Not tainted (2.6.25-rc9 #72) ... Call Trace: [<c044a5f9>] ? cgroup_exit+0x55/0x94 [<c0427acf>] ? do_exit+0x217/0x5ba [<c0427ed7>] ? do_group_exit+0.65/0x7c [<c0427efd>] ? sys_exit_group+0xf/0x11 [<c0404842>] ? syscall_call+0x7/0xb [<c05e0000>] ? init_cyrix+0x2fa/0x479 ... EIP: [<c04df671>] list_del+0x35/0x53 SS:ESP 0068:ebc7df4 ---[ end trace caffb7332252612b ]--- Fixing recursive fault but reboot is needed! After digging into the code and debugging, I finlly found out a race situation: do_exit() ->cgroup_exit() ->if (!list_empty(&tsk->cg_list)) list_del(&tsk->cg_list); cgroup_iter_start() ->cgroup_enable_task_cg_list() ->list_add(&tsk->cg_list, ..); In this case the list won't be deleted though the process has exited. We got two bug reports in the past, which seem to be the same bug as this one: http://lkml.org/lkml/2008/3/5/332 http://lkml.org/lkml/2007/10/17/224 Actually sometimes I got oops on list_del, sometimes oops on list_add. And I can change my test program a bit to trigger other oops. The patch has been tested both on x86_32 and x86_64. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: include hierarchy ids in /proc/<pid>/cgroupPaul Menage2008-04-111-0/+1
| | | | | | | | | | | | | | | | | | Extend the /proc/<pid>/cgroup file to include the appropriate hierarchy ID on each line. Currently this ID isn't really needed since a hierarchy can be completely identified by the set of subsystems bound to it, but this is likely to change in the near future in order to support stateless subsystems and merging/rebinding of subsystems. Getting this change into 2.6.25 reduces the need for an API change later. Signed-off-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: add cgroup support for enabling controllers at boot timePaul Menage2008-04-041-5/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The effects of cgroup_disable=foo are: - foo isn't auto-mounted if you mount all cgroups in a single hierarchy - foo isn't visible as an individually mountable subsystem As a result there will only ever be one call to foo->create(), at init time; all processes will stay in this group, and the group will never be mounted on a visible hierarchy. Any additional effects (e.g. not allocating metadata) are up to the foo subsystem. This doesn't handle early_init subsystems (their "disabled" bit isn't set be, but it could easily be extended to do so if any of the early_init systems wanted it - I think it would just involve some nastier parameter processing since it would occur before the command-line argument parser had been run. Hugh said: Ballpark figures, I'm trying to get this question out rather than processing the exact numbers: CONFIG_CGROUP_MEM_RES_CTLR adds 15% overhead to the affected paths, booting with cgroup_disable=memory cuts that back to 1% overhead (due to slightly bigger struct page). I'm no expert on distros, they may have no interest whatever in CONFIG_CGROUP_MEM_RES_CTLR=y; and the rest of us can easily build with or without it, or apply the cgroup_disable=memory patches. Unix bench's execl test result on x86_64 was == just after boot without mounting any cgroup fs.== mem_cgorup=off : Execl Throughput 43.0 3150.1 732.6 mem_cgroup=on : Execl Throughput 43.0 2932.6 682.0 == [lizf@cn.fujitsu.com: fix boot option parsing] Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* NULL noise: fs/*, mm/*, kernel/*Al Viro2008-03-301-2/+2
| | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: fix default notify_on_release settingLi Zefan2008-03-051-1/+3
| | | | | | | | | | | The documentation says the default value of notify_on_release of a child cgroup is inherited from its parent, which is reasonable, but the implementation just sets the flag disabled. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: remove dead code in cgroup_get_rootdir()Li Zefan2008-02-241-1/+0
| | | | | | | Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: remove duplicate code in find_css_set()Li Zefan2008-02-241-1/+0
| | | | | | | | | The list head res->tasks gets initialized twice in find_css_set(). Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: fix subsys bitopsLi Zefan2008-02-241-2/+2
| | | | | | | | | Cgroup uses unsigned long for subsys bitops, not unsigned long long. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: fix memory leak in cgroup_get_sb()Li Zefan2008-02-241-1/+4
| | | | | | | | | opts.release_agent is not kfree()ed in all necessary places. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroup: fix commentsLi Zefan2008-02-241-63/+79
| | | | | | | | | | | | fix: - comments about need_forkexit_callback - comments about release agent - typo and comment style, etc. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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