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-rw-r--r--Documentation/block/bfq-iosched.txt29
-rw-r--r--Documentation/block/null_blk.txt4
-rw-r--r--Documentation/process/submit-checklist.rst27
-rw-r--r--Documentation/translations/ja_JP/SubmitChecklist22
4 files changed, 47 insertions, 35 deletions
diff --git a/Documentation/block/bfq-iosched.txt b/Documentation/block/bfq-iosched.txt
index 98a8dd5ee385..1a0f2ac02eb6 100644
--- a/Documentation/block/bfq-iosched.txt
+++ b/Documentation/block/bfq-iosched.txt
@@ -20,13 +20,26 @@ for that device, by setting low_latency to 0. See Section 3 for
details on how to configure BFQ for the desired tradeoff between
latency and throughput, or on how to maximize throughput.
-BFQ has a non-null overhead, which limits the maximum IOPS that a CPU
-can process for a device scheduled with BFQ. To give an idea of the
-limits on slow or average CPUs, here are, first, the limits of BFQ for
-three different CPUs, on, respectively, an average laptop, an old
-desktop, and a cheap embedded system, in case full hierarchical
-support is enabled (i.e., CONFIG_BFQ_GROUP_IOSCHED is set), but
-CONFIG_DEBUG_BLK_CGROUP is not set (Section 4-2):
+As every I/O scheduler, BFQ adds some overhead to per-I/O-request
+processing. To give an idea of this overhead, the total,
+single-lock-protected, per-request processing time of BFQ---i.e., the
+sum of the execution times of the request insertion, dispatch and
+completion hooks---is, e.g., 1.9 us on an Intel Core i7-2760QM@2.40GHz
+(dated CPU for notebooks; time measured with simple code
+instrumentation, and using the throughput-sync.sh script of the S
+suite [1], in performance-profiling mode). To put this result into
+context, the total, single-lock-protected, per-request execution time
+of the lightest I/O scheduler available in blk-mq, mq-deadline, is 0.7
+us (mq-deadline is ~800 LOC, against ~10500 LOC for BFQ).
+
+Scheduling overhead further limits the maximum IOPS that a CPU can
+process (already limited by the execution of the rest of the I/O
+stack). To give an idea of the limits with BFQ, on slow or average
+CPUs, here are, first, the limits of BFQ for three different CPUs, on,
+respectively, an average laptop, an old desktop, and a cheap embedded
+system, in case full hierarchical support is enabled (i.e.,
+CONFIG_BFQ_GROUP_IOSCHED is set), but CONFIG_DEBUG_BLK_CGROUP is not
+set (Section 4-2):
- Intel i7-4850HQ: 400 KIOPS
- AMD A8-3850: 250 KIOPS
- ARM CortexTM-A53 Octa-core: 80 KIOPS
@@ -566,3 +579,5 @@ applications. Unset this tunable if you need/want to control weights.
Slightly extended version:
http://algogroup.unimore.it/people/paolo/disk_sched/bfq-v1-suite-
results.pdf
+
+[3] https://github.com/Algodev-github/S
diff --git a/Documentation/block/null_blk.txt b/Documentation/block/null_blk.txt
index 4cad1024fff7..41f0a3d33bbd 100644
--- a/Documentation/block/null_blk.txt
+++ b/Documentation/block/null_blk.txt
@@ -93,3 +93,7 @@ zoned=[0/1]: Default: 0
zone_size=[MB]: Default: 256
Per zone size when exposed as a zoned block device. Must be a power of two.
+
+zone_nr_conv=[nr_conv]: Default: 0
+ The number of conventional zones to create when block device is zoned. If
+ zone_nr_conv >= nr_zones, it will be reduced to nr_zones - 1.
diff --git a/Documentation/process/submit-checklist.rst b/Documentation/process/submit-checklist.rst
index 367353c54949..c88867b173d9 100644
--- a/Documentation/process/submit-checklist.rst
+++ b/Documentation/process/submit-checklist.rst
@@ -72,47 +72,44 @@ and elsewhere regarding submitting Linux kernel patches.
13) Has been build- and runtime tested with and without ``CONFIG_SMP`` and
``CONFIG_PREEMPT.``
-14) If the patch affects IO/Disk, etc: has been tested with and without
- ``CONFIG_LBDAF.``
+16) All codepaths have been exercised with all lockdep features enabled.
-15) All codepaths have been exercised with all lockdep features enabled.
+17) All new ``/proc`` entries are documented under ``Documentation/``
-16) All new ``/proc`` entries are documented under ``Documentation/``
-
-17) All new kernel boot parameters are documented in
+18) All new kernel boot parameters are documented in
``Documentation/admin-guide/kernel-parameters.rst``.
-18) All new module parameters are documented with ``MODULE_PARM_DESC()``
+19) All new module parameters are documented with ``MODULE_PARM_DESC()``
-19) All new userspace interfaces are documented in ``Documentation/ABI/``.
+20) All new userspace interfaces are documented in ``Documentation/ABI/``.
See ``Documentation/ABI/README`` for more information.
Patches that change userspace interfaces should be CCed to
linux-api@vger.kernel.org.
-20) Check that it all passes ``make headers_check``.
+21) Check that it all passes ``make headers_check``.
-21) Has been checked with injection of at least slab and page-allocation
+22) Has been checked with injection of at least slab and page-allocation
failures. See ``Documentation/fault-injection/``.
If the new code is substantial, addition of subsystem-specific fault
injection might be appropriate.
-22) Newly-added code has been compiled with ``gcc -W`` (use
+23) Newly-added code has been compiled with ``gcc -W`` (use
``make EXTRA_CFLAGS=-W``). This will generate lots of noise, but is good
for finding bugs like "warning: comparison between signed and unsigned".
-23) Tested after it has been merged into the -mm patchset to make sure
+24) Tested after it has been merged into the -mm patchset to make sure
that it still works with all of the other queued patches and various
changes in the VM, VFS, and other subsystems.
-24) All memory barriers {e.g., ``barrier()``, ``rmb()``, ``wmb()``} need a
+25) All memory barriers {e.g., ``barrier()``, ``rmb()``, ``wmb()``} need a
comment in the source code that explains the logic of what they are doing
and why.
-25) If any ioctl's are added by the patch, then also update
+26) If any ioctl's are added by the patch, then also update
``Documentation/ioctl/ioctl-number.txt``.
-26) If your modified source code depends on or uses any of the kernel
+27) If your modified source code depends on or uses any of the kernel
APIs or features that are related to the following ``Kconfig`` symbols,
then test multiple builds with the related ``Kconfig`` symbols disabled
and/or ``=m`` (if that option is available) [not all of these at the
diff --git a/Documentation/translations/ja_JP/SubmitChecklist b/Documentation/translations/ja_JP/SubmitChecklist
index 60c7c35ac517..b42220d3d46c 100644
--- a/Documentation/translations/ja_JP/SubmitChecklist
+++ b/Documentation/translations/ja_JP/SubmitChecklist
@@ -74,38 +74,34 @@ Linux カーネルパッチ投稿者向けチェックリスト
13: CONFIG_SMP, CONFIG_PREEMPT を有効にした場合と無効にした場合の両方で
ビルドした上、動作確認を行ってください。
-14: もしパッチがディスクのI/O性能などに影響を与えるようであれば、
- 'CONFIG_LBDAF'オプションを有効にした場合と無効にした場合の両方で
- テストを実施してみてください。
+14: lockdepの機能を全て有効にした上で、全てのコードパスを評価してください。
-15: lockdepの機能を全て有効にした上で、全てのコードパスを評価してください。
-
-16: /proc に新しいエントリを追加した場合には、Documentation/ 配下に
+15: /proc に新しいエントリを追加した場合には、Documentation/ 配下に
必ずドキュメントを追加してください。
-17: 新しいブートパラメータを追加した場合には、
+16: 新しいブートパラメータを追加した場合には、
必ずDocumentation/admin-guide/kernel-parameters.rst に説明を追加してください。
-18: 新しくmoduleにパラメータを追加した場合には、MODULE_PARM_DESC()を
+17: 新しくmoduleにパラメータを追加した場合には、MODULE_PARM_DESC()を
利用して必ずその説明を記述してください。
-19: 新しいuserspaceインタフェースを作成した場合には、Documentation/ABI/ に
+18: 新しいuserspaceインタフェースを作成した場合には、Documentation/ABI/ に
Documentation/ABI/README を参考にして必ずドキュメントを追加してください。
-20: 'make headers_check'を実行して全く問題がないことを確認してください。
+19: 'make headers_check'を実行して全く問題がないことを確認してください。
-21: 少なくともslabアロケーションとpageアロケーションに失敗した場合の
+20: 少なくともslabアロケーションとpageアロケーションに失敗した場合の
挙動について、fault-injectionを利用して確認してください。
Documentation/fault-injection/ を参照してください。
追加したコードがかなりの量であったならば、サブシステム特有の
fault-injectionを追加したほうが良いかもしれません。
-22: 新たに追加したコードは、`gcc -W'でコンパイルしてください。
+21: 新たに追加したコードは、`gcc -W'でコンパイルしてください。
このオプションは大量の不要なメッセージを出力しますが、
"warning: comparison between signed and unsigned" のようなメッセージは、
バグを見つけるのに役に立ちます。
-23: 投稿したパッチが -mm パッチセットにマージされた後、全ての既存のパッチや
+22: 投稿したパッチが -mm パッチセットにマージされた後、全ての既存のパッチや
VM, VFS およびその他のサブシステムに関する様々な変更と、現時点でも共存
できることを確認するテストを行ってください。