linux-toradex.git/mm/hugetlb_cgroup.c, branch v3.19-rc3

mm: hugetlb_cgroup: convert to lockless page counters

2014-12-11T01:41:04+00:00

Abandon the spinlock-protected byte counters in favor of the unlocked
page counters in the hugetlb controller as well.

Signed-off-by: Johannes Weiner 
Reviewed-by: Vladimir Davydov 
Acked-by: Michal Hocko 
Cc: Tejun Heo 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

hugetlb_cgroup: use lockdep_assert_held rather than spin_is_locked

2014-08-29T23:28:16+00:00

spin_lock may be an empty struct for !SMP configurations and so
arch_spin_is_locked may return unconditional 0 and trigger the VM_BUG_ON
even when the lock is held.

Replace spin_is_locked by lockdep_assert_held.  We will not BUG anymore
but it is questionable whether crashing makes a lot of sense in the
uncharge path.  Uncharge happens after the last page reference was
released so nobody should touch the page and the function doesn't update
any shared state except for res counter which uses synchronization of
its own.

Signed-off-by: Michal Hocko 
Reviewed-by: Aneesh Kumar K.V 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, hugetlb_cgroup: align hugetlb cgroup limit to hugepage size

2014-08-14T16:56:15+00:00

Memcg aligns memory.limit_in_bytes to PAGE_SIZE as part of the resource
counter since it makes no sense to allow a partial page to be charged.

As a result of the hugetlb cgroup using the resource counter, it is also
aligned to PAGE_SIZE but makes no sense unless aligned to the size of
the hugepage being limited.

Align hugetlb cgroup limit to hugepage size.

Signed-off-by: David Rientjes 
Acked-by: Michal Hocko 
Cc: "Aneesh Kumar K.V" 
Cc: Tejun Heo 
Cc: Li Zefan 
Cc: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroup: replace cgroup_add_cftypes() with cgroup_add_legacy_cftypes()

2014-07-15T15:05:09+00:00

Currently, cftypes added by cgroup_add_cftypes() are used for both the
unified default hierarchy and legacy ones and subsystems can mark each
file with either CFTYPE_ONLY_ON_DFL or CFTYPE_INSANE if it has to
appear only on one of them.  This is quite hairy and error-prone.
Also, we may end up exposing interface files to the default hierarchy
without thinking it through.

cgroup_subsys will grow two separate cftype addition functions and
apply each only on the hierarchies of the matching type.  This will
allow organizing cftypes in a lot clearer way and encourage subsystems
to scrutinize the interface which is being exposed in the new default
hierarchy.

In preparation, this patch adds cgroup_add_legacy_cftypes() which
currently is a simple wrapper around cgroup_add_cftypes() and replaces
all cgroup_add_cftypes() usages with it.

While at it, this patch drops a completely spurious return from
__hugetlb_cgroup_file_init().

This patch doesn't introduce any functional differences.

Signed-off-by: Tejun Heo 
Acked-by: Neil Horman 
Acked-by: Li Zefan 
Cc: Johannes Weiner 
Cc: Michal Hocko 
Cc: Aneesh Kumar K.V

cgroup: remove css_parent()

2014-05-16T17:22:48+00:00

cgroup in general is moving towards using cgroup_subsys_state as the
fundamental structural component and css_parent() was introduced to
convert from using cgroup->parent to css->parent.  It was quite some
time ago and we're moving forward with making css more prominent.

This patch drops the trivial wrapper css_parent() and let the users
dereference css->parent.  While at it, explicitly mark fields of css
which are public and immutable.

v2: New usage from device_cgroup.c converted.

Signed-off-by: Tejun Heo 
Acked-by: Michal Hocko 
Acked-by: Neil Horman 
Acked-by: "David S. Miller" 
Acked-by: Li Zefan 
Cc: Vivek Goyal 
Cc: Jens Axboe 
Cc: Peter Zijlstra 
Cc: Johannes Weiner

cgroup: replace cftype->trigger() with cftype->write()

2014-05-13T16:16:21+00:00

cftype->trigger() is pointless.  It's trivial to ignore the input
buffer from a regular ->write() operation.  Convert all ->trigger()
users to ->write() and remove ->trigger().

This patch doesn't introduce any visible behavior changes.

Signed-off-by: Tejun Heo 
Acked-by: Li Zefan 
Cc: Johannes Weiner 
Cc: Michal Hocko

cgroup: replace cftype->write_string() with cftype->write()

2014-05-13T16:16:21+00:00

Convert all cftype->write_string() users to the new cftype->write()
which maps directly to kernfs write operation and has full access to
kernfs and cgroup contexts.  The conversions are mostly mechanical.

* @css and @cft are accessed using of_css() and of_cft() accessors
  respectively instead of being specified as arguments.

* Should return @nbytes on success instead of 0.

* @buf is not trimmed automatically.  Trim if necessary.  Note that
  blkcg and netprio don't need this as the parsers already handle
  whitespaces.

cftype->write_string() has no user left after the conversions and
removed.

While at it, remove unnecessary local variable @p in
cgroup_subtree_control_write() and stale comment about
CGROUP_LOCAL_BUFFER_SIZE in cgroup_freezer.c.

This patch doesn't introduce any visible behavior changes.

v2: netprio was missing from conversion.  Converted.

Signed-off-by: Tejun Heo 
Acked-by: Aristeu Rozanski 
Acked-by: Vivek Goyal 
Acked-by: Li Zefan 
Cc: Jens Axboe 
Cc: Johannes Weiner 
Cc: Michal Hocko 
Cc: Neil Horman 
Cc: "David S. Miller"

cgroup: rename css_tryget() to css_tryget_online()

2014-05-13T16:11:01+00:00

Unlike the more usual refcnting, what css_tryget() provides is the
distinction between online and offline csses instead of protection
against upping a refcnt which already reached zero.  cgroup is
planning to provide actual tryget which fails if the refcnt already
reached zero.  Let's rename the existing trygets so that they clearly
indicate that they're onliness.

I thought about keeping the existing names as-are and introducing new
names for the planned actual tryget; however, given that each
controller participates in the synchronization of the online state, it
seems worthwhile to make it explicit that these functions are about
on/offline state.

Rename css_tryget() to css_tryget_online() and css_tryget_from_dir()
to css_tryget_online_from_dir().  This is pure rename.

v2: cgroup_freezer grew new usages of css_tryget().  Update
    accordingly.

Signed-off-by: Tejun Heo 
Acked-by: Johannes Weiner 
Acked-by: Michal Hocko 
Acked-by: Li Zefan 
Cc: Vivek Goyal 
Cc: Jens Axboe 
Cc: Peter Zijlstra 
Cc: Paul Mackerras 
Cc: Ingo Molnar 
Cc: Arnaldo Carvalho de Melo

cgroup: drop const from @buffer of cftype->write_string()

2014-03-19T14:23:54+00:00

cftype->write_string() just passes on the writeable buffer from kernfs
and there's no reason to add const restriction on the buffer.  The
only thing const achieves is unnecessarily complicating parsing of the
buffer.  Drop const from @buffer.

Signed-off-by: Tejun Heo 
Acked-by: Li Zefan 
Cc: Peter Zijlstra 
Cc: Paul Mackerras 
Cc: Ingo Molnar 
Cc: Arnaldo Carvalho de Melo 
Cc: Daniel Borkmann 
Cc: Michal Hocko                                            
Cc: Johannes Weiner 
Cc: Balbir Singh 
Cc: KAMEZAWA Hiroyuki

cgroup: clean up cgroup_subsys names and initialization

2014-02-08T15:36:58+00:00

cgroup_subsys is a bit messier than it needs to be.

* The name of a subsys can be different from its internal identifier
  defined in cgroup_subsys.h.  Most subsystems use the matching name
  but three - cpu, memory and perf_event - use different ones.

* cgroup_subsys_id enums are postfixed with _subsys_id and each
  cgroup_subsys is postfixed with _subsys.  cgroup.h is widely
  included throughout various subsystems, it doesn't and shouldn't
  have claim on such generic names which don't have any qualifier
  indicating that they belong to cgroup.

* cgroup_subsys->subsys_id should always equal the matching
  cgroup_subsys_id enum; however, we require each controller to
  initialize it and then BUG if they don't match, which is a bit
  silly.

This patch cleans up cgroup_subsys names and initialization by doing
the followings.

* cgroup_subsys_id enums are now postfixed with _cgrp_id, and each
  cgroup_subsys with _cgrp_subsys.

* With the above, renaming subsys identifiers to match the userland
  visible names doesn't cause any naming conflicts.  All non-matching
  identifiers are renamed to match the official names.

  cpu_cgroup -> cpu
  mem_cgroup -> memory
  perf -> perf_event

* controllers no longer need to initialize ->subsys_id and ->name.
  They're generated in cgroup core and set automatically during boot.

* Redundant cgroup_subsys declarations removed.

* While updating BUG_ON()s in cgroup_init_early(), convert them to
  WARN()s.  BUGging that early during boot is stupid - the kernel
  can't print anything, even through serial console and the trap
  handler doesn't even link stack frame properly for back-tracing.

This patch doesn't introduce any behavior changes.

v2: Rebased on top of fe1217c4f3f7 ("net: net_cls: move cgroupfs
    classid handling into core").

Signed-off-by: Tejun Heo 
Acked-by: Neil Horman 
Acked-by: "David S. Miller" 
Acked-by: "Rafael J. Wysocki" 
Acked-by: Michal Hocko 
Acked-by: Peter Zijlstra 
Acked-by: Aristeu Rozanski 
Acked-by: Ingo Molnar 
Acked-by: Li Zefan 
Cc: Johannes Weiner 
Cc: Balbir Singh 
Cc: KAMEZAWA Hiroyuki 
Cc: Serge E. Hallyn 
Cc: Vivek Goyal 
Cc: Thomas Graf