__GFP_WAIT has been used to identify atomic context in callers that hold
spinlocks or are in interrupts. They are expected to be high priority and
have access one of two watermarks lower than "min" which can be referred
to as the "atomic reserve". __GFP_HIGH users get access to the first
lower watermark and can be called the "high priority reserve".
Over time, callers had a requirement to not block when fallback options
were available. Some have abused __GFP_WAIT leading to a situation where
an optimisitic allocation with a fallback option can access atomic
reserves.
This patch uses __GFP_ATOMIC to identify callers that are truely atomic,
cannot sleep and have no alternative. High priority users continue to use
__GFP_HIGH. __GFP_DIRECT_RECLAIM identifies callers that can sleep and
are willing to enter direct reclaim. __GFP_KSWAPD_RECLAIM to identify
callers that want to wake kswapd for background reclaim. __GFP_WAIT is
redefined as a caller that is willing to enter direct reclaim and wake
kswapd for background reclaim.
This patch then converts a number of sites
o __GFP_ATOMIC is used by callers that are high priority and have memory
pools for those requests. GFP_ATOMIC uses this flag.
o Callers that have a limited mempool to guarantee forward progress clear
__GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall
into this category where kswapd will still be woken but atomic reserves
are not used as there is a one-entry mempool to guarantee progress.
o Callers that are checking if they are non-blocking should use the
helper gfpflags_allow_blocking() where possible. This is because
checking for __GFP_WAIT as was done historically now can trigger false
positives. Some exceptions like dm-crypt.c exist where the code intent
is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to
flag manipulations.
o Callers that built their own GFP flags instead of starting with GFP_KERNEL
and friends now also need to specify __GFP_KSWAPD_RECLAIM.
The first key hazard to watch out for is callers that removed __GFP_WAIT
and was depending on access to atomic reserves for inconspicuous reasons.
In some cases it may be appropriate for them to use __GFP_HIGH.
The second key hazard is callers that assembled their own combination of
GFP flags instead of starting with something like GFP_KERNEL. They may
now wish to specify __GFP_KSWAPD_RECLAIM. It's almost certainly harmless
if it's missed in most cases as other activity will wake kswapd.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In a recent change, we made a bool into a tristate in:
"drivers/staging: make android tegra_ion.c properly tristate", since it
was self evident that was the original intention. However on the final
link phase we'll see an allmodconfig fail with:
ERROR: "ion_device_add_heap" [drivers/staging/android/ion/tegra/tegra_ion.ko] undefined!
ERROR: "ion_heap_create" [drivers/staging/android/ion/tegra/tegra_ion.ko] undefined!
ERROR: "ion_device_create" [drivers/staging/android/ion/tegra/tegra_ion.ko] undefined!
ERROR: "ion_heap_destroy" [drivers/staging/android/ion/tegra/tegra_ion.ko] undefined!
ERROR: "ion_device_destroy" [drivers/staging/android/ion/tegra/tegra_ion.ko] undefined!
Export the above using the non GPL specific export, since that is what
the rest of the ion code base does.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Arve Hjønnevåg" <arve@android.com>
Cc: Riley Andrews <riandrews@android.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Markus Elfring <elfring@users.sourceforge.net>
Cc: devel@driverdev.osuosl.org
Cc: linux-tegra@vger.kernel.org
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Kconfig currently controlling compilation of this code is:
drivers/staging/android/Kconfig:config ANDROID_TIMED_OUTPUT
drivers/staging/android/Kconfig: bool "Timed output class driver"
...meaning that it currently is not being built as a module by anyone.
Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.
Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.
We replace module.h with init.h and export.h ; the latter since this
file does actually export some symbols.
We also delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.
Cc: "Arve Hjønnevåg" <arve@android.com>
Cc: Riley Andrews <riandrews@android.com>
Cc: devel@driverdev.osuosl.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Kconfig currently controlling compilation of this code is:
drivers/staging/android/Kconfig:config ANDROID_LOW_MEMORY_KILLER
drivers/staging/android/Kconfig: bool "Android Low Memory Killer"
...meaning that it currently is not being built as a module by anyone.
Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.
Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.
We replace module.h with init.h and moduleparam.h ; the latter since
this file was previously implicitly relying on getting that header.
We also delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.
Cc: "Arve Hjønnevåg" <arve@android.com>
Cc: Riley Andrews <riandrews@android.com>
Cc: devel@driverdev.osuosl.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Kconfig currently controlling compilation of this code is:
staging/android/Kconfig:config SW_SYNC
staging/android/Kconfig: bool "Software synchronization objects"
...meaning that it currently is not being built as a module by anyone.
Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.
Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.
We also delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.
Cc: "Arve Hjønnevåg" <arve@android.com>
Cc: Riley Andrews <riandrews@android.com>
Cc: devel@driverdev.osuosl.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Kconfig currently controlling compilation of this code is:
drivers/staging/android/Kconfig:config ASHMEM
drivers/staging/android/Kconfig: bool "Enable the Anonymous Shared Memory Subsystem"
...meaning that it currently is not being built as a module by anyone.
Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.
Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.
We replace module.h with init.h and export.h ; the latter since this
file uses the global THIS_MODULE.
We also delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.
Cc: "Arve Hjønnevåg" <arve@android.com>
Cc: Riley Andrews <riandrews@android.com>
Cc: devel@driverdev.osuosl.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Kconfig currently controlling compilation of this code is:
drivers/staging/android/ion/Kconfig:config ION_TEGRA
drivers/staging/android/ion/Kconfig: tristate "Ion for Tegra"
...which led me to incorrectly conclude this file was built modular
earlier. However the above CONFIG is just used to enter the dir and
once we do enter that dir, we see the build is unconditional:
drivers/staging/android/ion/Makefile:obj-$(CONFIG_ION_TEGRA) += tegra/
drivers/staging/android/ion/tegra/Makefile:obj-y += tegra_ion.o
...meaning that it currently is not being built as a module by anyone.
However, given that the Kconfig did explicitly choose tristate, and that
the dummy ion driver is (functionally) tristate, I chose to make the
Makefile do the right thing for it to build as a module.
After this change, on an ARM allmodconfig, we see:
CC [M] drivers/staging/android/ion/tegra/tegra_ion.o
so it does build OK as a module. I can't vouch for the modular
functionality however, so consider this compile tested only.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Arve Hjønnevåg" <arve@android.com>
Cc: Riley Andrews <riandrews@android.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Markus Elfring <elfring@users.sourceforge.net>
Cc: devel@driverdev.osuosl.org
Cc: linux-tegra@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Kconfig currently controlling compilation of this code is:
drivers/staging/android/ion/Kconfig:menuconfig ION
drivers/staging/android/ion/Kconfig: bool "Ion Memory Manager"
...meaning that it currently is not being built as a module by anyone.
Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.
Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Arve Hjønnevåg" <arve@android.com>
Cc: Riley Andrews <riandrews@android.com>
Cc: devel@driverdev.osuosl.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It was observed that setting TIF_MEMDIE before sending SIGKILL at
oom_kill_process() allows memory reserves to be depleted by allocations
which are not needed for terminating the OOM victim.
This patch reverts commit 6bc2b856bb ("staging: android: lowmemorykiller:
set TIF_MEMDIE before send kill sig"), for oom_kill_process() was updated
to send SIGKILL before setting TIF_MEMDIE.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix 'cannot understand function prototype' and 'No description found for
parameter' kernel-doc warnings by replacing /** with /* in regular
comments
Signed-off-by: Cristina Moraru <cristina.moraru09@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix 'No description found for parameter 'prot_mask'' and 'Excess
struct/union/enum/typedef member 'prot_masks' description in
'ashmem_area'' warnings by removing typo
Signed-off-by: Cristina Moraru <cristina.moraru09@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch is intended to fix the checkpatch warning for ``block``
comments for staging/android driver.
Signed-off-by: Sriram Raghunathan <sriram@marirs.net.in>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We discussed a bit with the folks on the Cc: list below what to do
with ION. Two big take-aways:
- High-performance drivers (like gpus) always want to play tricks with
coherency and will lie to the dma api (radeon, nouveau, i915 gpu
drivers all do so in upstream). What needs to be done here is fill
gaps in dma-buf so that we can do this without breaking the dma-api
expections of other clients like v4l. The consesus is that hw won't
stop needing these tricks anytime soon.
- Placement constraints for shared buffers won't be solved any other
way than through something platform-specific like ion with
platform-specific knowledge in userspace in something like gralloc.
For general-purpose devices where this assumption would be painful
for userspace (like servers) the consensus is that such devices will
have proper MMUs where placement constraint handling is fairly
irrelevant.
Hence it is reasonable to destage ion as-is without changing the
overall design to enable these use-cases and just fixing up a these
few fairly minor things. Since there won't relly be an open-source
userspace for ion (and hence drm maintainers won't take it) the
proposal is to eventually move it to drivers/android/ion.[hc]. Laura
would be ok with being maintainer once this is all done and ion is
destaged.
Note that Thiago is working on exposing the cpu cache flushing for
cpu access from userspace through mmaps so this is alread in progress.
Also adding him to the Cc: list.
v2: Add ION_IOC_IMPORT to the list of ioctl that probably should go.
Cc: Laura Abbott <labbott@redhat.com>
Cc: sumit.semwal@linaro.org
Cc: laurent.pinchart@ideasonboard.com
Cc: ghackmann@google.com
Cc: robdclark@gmail.com
Cc: david.brown@arm.com
Cc: romlem@google.com
Cc: Tiago Vignatti <tiago.vignatti@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The linux kernel coding style discourages use of braces for single
statement blocks. This patch removes the unnecessary braces.
The warning was detected using checkpatch.pl. Coccinelle was used
to make the change.
Signed-off-by: Shraddha Barke <shraddha.6596@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fix two CHECK issues by checkpatch.pl with --strict:
Alignment should match open parenthesis
Signed-off-by: Peng Sun <sironhide0null@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fix two CHECK issues by checkpatch.pl with --strict:
No space is necessary after a cast
Signed-off-by: Peng Sun <sironhide0null@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fix a CHECK style issue by checkpatch.pl with --strict:
spaces preferred around that '-'
Signed-off-by: Peng Sun <sironhide0null@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull SG updates from Jens Axboe:
"This contains a set of scatter-gather related changes/fixes for 4.3:
- Add support for limited chaining of sg tables even for
architectures that do not set ARCH_HAS_SG_CHAIN. From Christoph.
- Add sg chain support to target_rd. From Christoph.
- Fixup open coded sg->page_link in crypto/omap-sham. From
Christoph.
- Fixup open coded crypto ->page_link manipulation. From Dan.
- Also from Dan, automated fixup of manual sg_unmark_end()
manipulations.
- Also from Dan, automated fixup of open coded sg_phys()
implementations.
- From Robert Jarzmik, addition of an sg table splitting helper that
drivers can use"
* 'for-4.3/sg' of git://git.kernel.dk/linux-block:
lib: scatterlist: add sg splitting function
scatterlist: use sg_phys()
crypto/omap-sham: remove an open coded access to ->page_link
scatterlist: remove open coded sg_unmark_end instances
crypto: replace scatterwalk_sg_chain with sg_chain
target/rd: always chain S/G list
scatterlist: allow limited chaining without ARCH_HAS_SG_CHAIN
Mel Gorman
Muhammad Falak R Wani
Paul Gortmaker
Tetsuo Handa
Cristina Moraru
Rohit kumar
Sriram Raghunathan
Greg Kroah-Hartman
Shawn Lin
Daniel Vetter
Junesung Lee
Shraddha Barke
Trung Thanh Le
Peng Sun
Kirill A. Shutemov
Linus Torvalds