mem_cgroup_force_empty_list currently tries to remove all pages from
the given LRU. To prevent from temoporary failures (EBUSY returned by
mem_cgroup_move_parent) it uses a margin to the current LRU pages and
returns the true if there are still some pages left on the list.
If we consider that mem_cgroup_move_parent fails only when it is racing
with somebody else removing (uncharging) the page or when the page is
migrated then it is obvious that all those failures are only temporal
and so we can safely retry later.
Let's get rid of the safety margin and make the loop really wait for
the empty LRU. The caller should still make sure that all charges have
been removed from the res_counter because mem_cgroup_replace_page_cache
might add a page to the LRU after the list_empty check (it doesn't touch
res_counter though).
This catches most of the cases except for shmem which might call
mem_cgroup_replace_page_cache with a page which is not charged and on
the LRU yet but this was the case also without this patch. In order to
fix this we need a guarantee that try_get_mem_cgroup_from_page falls
back to the current mm's cgroup so it needs css_tryget to fail. This
will be fixed up in a later patch because it needs a help from cgroup
core (pre_destroy has to be called after css is cleared).
Although mem_cgroup_pre_destroy can still fail (if a new task or a new
sub-group appears) there is no reason to retry pre_destroy callback from
the cgroup core. This means that __DEPRECATED_clear_css_refs has lost
its meaning and it can be removed.
Changes since v2
- remove __DEPRECATED_clear_css_refs
Changes since v1
- use kerndoc
- be more specific about mem_cgroup_move_parent possible failures
Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Tejun Heo <tj@kernel.org> Reviewed-by: Glauber Costa <glommer@parallels.com> Signed-off-by: Tejun Heo <tj@kernel.org>
The root cgroup cannot be destroyed so we never hit it down the
mem_cgroup_pre_destroy path and mem_cgroup_force_empty_write shouldn't
even try to do anything if called for the root.
This means that mem_cgroup_move_parent doesn't have to bother with the
root cgroup and it can assume it can always move charges upwards.
Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Tejun Heo <tj@kernel.org> Reviewed-by: Glauber Costa <glommer@parallels.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Michal Hocko [Fri, 26 Oct 2012 11:37:28 +0000 (13:37 +0200)]
memcg: split mem_cgroup_force_empty into reclaiming and reparenting parts
mem_cgroup_force_empty did two separate things depending on free_all
parameter from the very beginning. It either reclaimed as many pages as
possible and moved the rest to the parent or just moved charges to the
parent. The first variant is used as memory.force_empty callback while
the later is used from the mem_cgroup_pre_destroy.
The whole games around gotos are far from being nice and there is no
reason to keep those two functions inside one. Let's split them and
also move the responsibility for css reference counting to their callers
to make to code easier.
This patch doesn't have any functional changes.
Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Tejun Heo <tj@kernel.org> Reviewed-by: Glauber Costa <glommer@parallels.com> Signed-off-by: Tejun Heo <tj@kernel.org>
1. Never ever publish a device in the system before it has been setup
to a usable state.
2. Unregister the device _BEFORE_ taking away any resources it may be
using.
3. Don't check clks against NULL.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> Signed-off-by: Chris Ball <cjb@laptop.org>
Balaji T K [Thu, 25 Oct 2012 15:58:35 +0000 (21:28 +0530)]
mmc: omap_hsmmc: remove warning message for debounce clock
MMC debounce clock is applicable only for omap2430, warning message gets
printed when enable fails for debounce clock. Remove the get debounce clock
failure message as it is noisy for other platforms.
Signed-off-by: Balaji T K <balajitk@ti.com> Reported-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Chris Ball <cjb@laptop.org>
A recent commit "mmc: sh_mmcif: fix clock management" has introduced a
use after free bug in sh_mmcif.c: in sh_mmcif_remove() the call to
mmc_free_host() frees private driver data, therefore using it afterwards
is a bug. Revert that hunk.
The SDHCI standard defines a 256 byte register set but a device
that specifies a larger iomem region is not an error. Alter the
message condition accordingly.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Chris Ball <cjb@laptop.org>
Whenever WLAN receives scheduling msg from BT, it reduces tx power
based on RSSI level. And then BT starts simultaneous transmission
along with WLAN. Sometimes HW MAC compares tx power that is used
prior to power reduction which is causing BT transmission to defer.
Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
This reduced the power consumption to half in full and network sleep.
Cc: stable@vger.kernel.org Cc: Paul Stewart <pstew@chromium.org> Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
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