[PATCH 0/4] Fix trivial nits in Documentation/admin-guide/mm

[PATCH 0/4] Fix trivial nits in Documentation/admin-guide/mm

[SeongJae Park]

This patchset fixes trivial nits in admin guide documents for DAMON and
pagemap.

SeongJae Park (4):
  Docs/admin-guide/mm/damon/start: Fix wrong example commands
  Docs/admin-guide/mm/damon/start: Fix a wrong link
  Docs/admin-guide/mm/damon/start: Simplify the content
  Docs/admin-guide/mm/pagemap: Wordsmith page flags descriptions

 Documentation/admin-guide/mm/damon/start.rst | 123 ++++++++++---------
 Documentation/admin-guide/mm/pagemap.rst     |  53 ++++----
 2 files changed, 93 insertions(+), 83 deletions(-)

-- 
2.17.1

[PATCH 1/4] Docs/admin-guide/mm/damon/start: Fix wrong example commands

[SeongJae Park]

Some of the example commands in DAMON getting started guide are
outdated, missing sudo, or just wrong.  This commit fixes those.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/admin-guide/mm/damon/start.rst | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/Documentation/admin-guide/mm/damon/start.rst b/Documentation/admin-guide/mm/damon/start.rst
index 51503cf90ca2..3ad8bbed9b18 100644
--- a/Documentation/admin-guide/mm/damon/start.rst
+++ b/Documentation/admin-guide/mm/damon/start.rst
@@ -19,7 +19,7 @@ your workload. ::
     # mount -t debugfs none /sys/kernel/debug/
     # git clone https://github.com/awslabs/damo
     # ./damo/damo record $(pidof <your workload>)
-    # ./damo/damo report heat --plot_ascii
+    # ./damo/damo report heats --heatmap stdout
 
 The final command draws the access heatmap of ``<your workload>``.  The heatmap
 shows which memory region (x-axis) is accessed when (y-axis) and how frequently
@@ -94,9 +94,9 @@ Visualizing Recorded Patterns
 The following three commands visualize the recorded access patterns and save
 the results as separate image files. ::
 
-    $ damo report heats --heatmap access_pattern_heatmap.png
-    $ damo report wss --range 0 101 1 --plot wss_dist.png
-    $ damo report wss --range 0 101 1 --sortby time --plot wss_chron_change.png
+    $ sudo damo report heats --heatmap access_pattern_heatmap.png
+    $ sudo damo report wss --range 0 101 1 --plot wss_dist.png
+    $ sudo damo report wss --range 0 101 1 --sortby time --plot wss_chron_change.png
 
 - ``access_pattern_heatmap.png`` will visualize the data access pattern in a
   heatmap, showing which memory region (y-axis) got accessed when (x-axis)
@@ -115,9 +115,9 @@ Data Access Pattern Aware Memory Management
 Below three commands make every memory region of size >=4K that doesn't
 accessed for >=60 seconds in your workload to be swapped out. ::
 
-    $ echo "#min-size max-size min-acc max-acc min-age max-age action" > scheme
-    $ echo "4K        max      0       0       60s     max     pageout" >> scheme
-    $ damo schemes -c my_thp_scheme <pid of your workload>
+    $ echo "#min-size max-size min-acc max-acc min-age max-age action" > test_scheme
+    $ echo "4K        max      0       0       60s     max     pageout" >> test_scheme
+    $ damo schemes -c test_scheme <pid of your workload>
 
 .. [1] https://damonitor.github.io/doc/html/v17/admin-guide/mm/damon/start.html#visualizing-recorded-patterns
 .. [2] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.1.png.html
-- 
2.17.1

[PATCH 2/4] Docs/admin-guide/mm/damon/start: Fix a wrong link

[SeongJae Park]

The 'Getting Started' of DAMON is providing a link to DAMON's user
interface document while saying about its user space tool's detailed
usages.  This commit fixes the link.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/admin-guide/mm/damon/start.rst | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/mm/damon/start.rst b/Documentation/admin-guide/mm/damon/start.rst
index 3ad8bbed9b18..5f3b22cafc76 100644
--- a/Documentation/admin-guide/mm/damon/start.rst
+++ b/Documentation/admin-guide/mm/damon/start.rst
@@ -6,7 +6,9 @@ Getting Started
 
 This document briefly describes how you can use DAMON by demonstrating its
 default user space tool.  Please note that this document describes only a part
-of its features for brevity.  Please refer to :doc:`usage` for more details.
+of its features for brevity.  Please refer to the usage `doc
+<https://github.com/awslabs/damo/blob/next/USAGE.md>`_ of the tool for more
+details.
 
 
 TL; DR
-- 
2.17.1

[PATCH 3/4] Docs/admin-guide/mm/damon/start: Simplify the content

[SeongJae Park]

Information in 'TL; DR' section of 'Getting Started' is duplicated in
other parts of the doc.  It is also asking readers to visit the access
pattern visualizations gallery web site to show the results of example
visualization commands, while the users of the commands can use terminal
output.

To make the doc simple, this commit removes the duplicated 'TL; DR'
section and replaces the visualization example commands with versions
using terminal outputs.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/admin-guide/mm/damon/start.rst | 113 ++++++++++---------
 1 file changed, 60 insertions(+), 53 deletions(-)

diff --git a/Documentation/admin-guide/mm/damon/start.rst b/Documentation/admin-guide/mm/damon/start.rst
index 5f3b22cafc76..4d5ca2c46288 100644
--- a/Documentation/admin-guide/mm/damon/start.rst
+++ b/Documentation/admin-guide/mm/damon/start.rst
@@ -11,38 +11,6 @@ of its features for brevity.  Please refer to the usage `doc
 details.
 
 
-TL; DR
-======
-
-Follow the commands below to monitor and visualize the memory access pattern of
-your workload. ::
-
-    # # build the kernel with CONFIG_DAMON_*=y, install it, and reboot
-    # mount -t debugfs none /sys/kernel/debug/
-    # git clone https://github.com/awslabs/damo
-    # ./damo/damo record $(pidof <your workload>)
-    # ./damo/damo report heats --heatmap stdout
-
-The final command draws the access heatmap of ``<your workload>``.  The heatmap
-shows which memory region (x-axis) is accessed when (y-axis) and how frequently
-(number; the higher the more accesses have been observed). ::
-
-    111111111111111111111111111111111111111111111111111111110000
-    111121111111111111111111111111211111111111111111111111110000
-    000000000000000000000000000000000000000000000000001555552000
-    000000000000000000000000000000000000000000000222223555552000
-    000000000000000000000000000000000000000011111677775000000000
-    000000000000000000000000000000000000000488888000000000000000
-    000000000000000000000000000000000177888400000000000000000000
-    000000000000000000000000000046666522222100000000000000000000
-    000000000000000000000014444344444300000000000000000000000000
-    000000000000000002222245555510000000000000000000000000000000
-    # access_frequency:  0  1  2  3  4  5  6  7  8  9
-    # x-axis: space (140286319947776-140286426374096: 101.496 MiB)
-    # y-axis: time (605442256436361-605479951866441: 37.695430s)
-    # resolution: 60x10 (1.692 MiB and 3.770s for each character)
-
-
 Prerequisites
 =============
 
@@ -93,22 +61,66 @@ pattern in the ``damon.data`` file.
 Visualizing Recorded Patterns
 =============================
 
-The following three commands visualize the recorded access patterns and save
-the results as separate image files. ::
-
-    $ sudo damo report heats --heatmap access_pattern_heatmap.png
-    $ sudo damo report wss --range 0 101 1 --plot wss_dist.png
-    $ sudo damo report wss --range 0 101 1 --sortby time --plot wss_chron_change.png
-
-- ``access_pattern_heatmap.png`` will visualize the data access pattern in a
-  heatmap, showing which memory region (y-axis) got accessed when (x-axis)
-  and how frequently (color).
-- ``wss_dist.png`` will show the distribution of the working set size.
-- ``wss_chron_change.png`` will show how the working set size has
-  chronologically changed.
-
-You can view the visualizations of this example workload at [1]_.
-Visualizations of other realistic workloads are available at [2]_ [3]_ [4]_.
+You can visualize the pattern in a heatmap, showing which memory region
+(x-axis) got accessed when (y-axis) and how frequently (number).::
+
+    $ sudo damo report heats --heatmap stdout
+    22222222222222222222222222222222222222211111111111111111111111111111111111111100
+    44444444444444444444444444444444444444434444444444444444444444444444444444443200
+    44444444444444444444444444444444444444433444444444444444444444444444444444444200
+    33333333333333333333333333333333333333344555555555555555555555555555555555555200
+    33333333333333333333333333333333333344444444444444444444444444444444444444444200
+    22222222222222222222222222222222222223355555555555555555555555555555555555555200
+    00000000000000000000000000000000000000288888888888888888888888888888888888888400
+    00000000000000000000000000000000000000288888888888888888888888888888888888888400
+    33333333333333333333333333333333333333355555555555555555555555555555555555555200
+    88888888888888888888888888888888888888600000000000000000000000000000000000000000
+    88888888888888888888888888888888888888600000000000000000000000000000000000000000
+    33333333333333333333333333333333333333444444444444444444444444444444444444443200
+    00000000000000000000000000000000000000288888888888888888888888888888888888888400
+    [...]
+    # access_frequency:  0  1  2  3  4  5  6  7  8  9
+    # x-axis: space (139728247021568-139728453431248: 196.848 MiB)
+    # y-axis: time (15256597248362-15326899978162: 1 m 10.303 s)
+    # resolution: 80x40 (2.461 MiB and 1.758 s for each character)
+
+You can also visualize the distribution of the working set size, sorted by the
+size.::
+
+    $ sudo damo report wss --range 0 101 10
+    # <percentile> <wss>
+    # target_id     18446632103789443072
+    # avr:  107.708 MiB
+      0             0 B |                                                           |
+     10      95.328 MiB |****************************                               |
+     20      95.332 MiB |****************************                               |
+     30      95.340 MiB |****************************                               |
+     40      95.387 MiB |****************************                               |
+     50      95.387 MiB |****************************                               |
+     60      95.398 MiB |****************************                               |
+     70      95.398 MiB |****************************                               |
+     80      95.504 MiB |****************************                               |
+     90     190.703 MiB |*********************************************************  |
+    100     196.875 MiB |***********************************************************|
+
+Using ``--sortby`` option with the above command, you can show how the working
+set size has chronologically changed.::
+
+    $ sudo damo report wss --range 0 101 10 --sortby time
+    # <percentile> <wss>
+    # target_id     18446632103789443072
+    # avr:  107.708 MiB
+      0       3.051 MiB |                                                           |
+     10     190.703 MiB |***********************************************************|
+     20      95.336 MiB |*****************************                              |
+     30      95.328 MiB |*****************************                              |
+     40      95.387 MiB |*****************************                              |
+     50      95.332 MiB |*****************************                              |
+     60      95.320 MiB |*****************************                              |
+     70      95.398 MiB |*****************************                              |
+     80      95.398 MiB |*****************************                              |
+     90      95.340 MiB |*****************************                              |
+    100      95.398 MiB |*****************************                              |
 
 
 Data Access Pattern Aware Memory Management
@@ -120,8 +132,3 @@ accessed for >=60 seconds in your workload to be swapped out. ::
     $ echo "#min-size max-size min-acc max-acc min-age max-age action" > test_scheme
     $ echo "4K        max      0       0       60s     max     pageout" >> test_scheme
     $ damo schemes -c test_scheme <pid of your workload>
-
-.. [1] https://damonitor.github.io/doc/html/v17/admin-guide/mm/damon/start.html#visualizing-recorded-patterns
-.. [2] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.1.png.html
-.. [3] https://damonitor.github.io/test/result/visual/latest/rec.wss_sz.png.html
-.. [4] https://damonitor.github.io/test/result/visual/latest/rec.wss_time.png.html
-- 
2.17.1

[PATCH 4/4] Docs/admin-guide/mm/pagemap: Wordsmith page flags descriptions

[SeongJae Park]

Some descriptions of page flags in 'pagemap.rst' are written in
assumption of none-rst, which respects every new line, as below:

    7 - SLAB
       page is managed by the SLAB/SLOB/SLUB/SLQB kernel memory allocator
       When compound page is used, SLUB/SLQB will only set this flag on the head

Because rst ignores the new line between the first sentence and second
sentence, resulting html looks a little bit weird, as below.

    7 - SLAB
    page is managed by the SLAB/SLOB/SLUB/SLQB kernel memory allocator When
                                                                       ^
    compound page is used, SLUB/SLQB will only set this flag on the head
    page; SLOB will not flag it at all.

This commit makes it more natural and consistent with other parts in the
rendered version.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/admin-guide/mm/pagemap.rst | 53 ++++++++++++------------
 1 file changed, 27 insertions(+), 26 deletions(-)

diff --git a/Documentation/admin-guide/mm/pagemap.rst b/Documentation/admin-guide/mm/pagemap.rst
index fdc19fbc1083..242d84315066 100644
--- a/Documentation/admin-guide/mm/pagemap.rst
+++ b/Documentation/admin-guide/mm/pagemap.rst
@@ -90,13 +90,14 @@ Short descriptions to the page flags
 ====================================
 
 0 - LOCKED
-   page is being locked for exclusive access, e.g. by undergoing read/write IO
+   The page is being locked for exclusive access, e.g. by undergoing read/write
+   IO.
 7 - SLAB
-   page is managed by the SLAB/SLOB/SLUB/SLQB kernel memory allocator
+   The page is managed by the SLAB/SLOB/SLUB/SLQB kernel memory allocator.
    When compound page is used, SLUB/SLQB will only set this flag on the head
    page; SLOB will not flag it at all.
 10 - BUDDY
-    a free memory block managed by the buddy system allocator
+    A free memory block managed by the buddy system allocator.
     The buddy system organizes free memory in blocks of various orders.
     An order N block has 2^N physically contiguous pages, with the BUDDY flag
     set for and _only_ for the first page.
@@ -112,65 +113,65 @@ Short descriptions to the page flags
 16 - COMPOUND_TAIL
     A compound page tail (see description above).
 17 - HUGE
-    this is an integral part of a HugeTLB page
+    This is an integral part of a HugeTLB page.
 19 - HWPOISON
-    hardware detected memory corruption on this page: don't touch the data!
+    Hardware detected memory corruption on this page: don't touch the data!
 20 - NOPAGE
-    no page frame exists at the requested address
+    No page frame exists at the requested address.
 21 - KSM
-    identical memory pages dynamically shared between one or more processes
+    Identical memory pages dynamically shared between one or more processes.
 22 - THP
-    contiguous pages which construct transparent hugepages
+    Contiguous pages which construct transparent hugepages.
 23 - OFFLINE
-    page is logically offline
+    The page is logically offline.
 24 - ZERO_PAGE
-    zero page for pfn_zero or huge_zero page
+    Zero page for pfn_zero or huge_zero page.
 25 - IDLE
-    page has not been accessed since it was marked idle (see
+    The page has not been accessed since it was marked idle (see
     :ref:`Documentation/admin-guide/mm/idle_page_tracking.rst <idle_page_tracking>`).
     Note that this flag may be stale in case the page was accessed via
     a PTE. To make sure the flag is up-to-date one has to read
     ``/sys/kernel/mm/page_idle/bitmap`` first.
 26 - PGTABLE
-    page is in use as a page table
+    The page is in use as a page table.
 
 IO related page flags
 ---------------------
 
 1 - ERROR
-   IO error occurred
+   IO error occurred.
 3 - UPTODATE
-   page has up-to-date data
+   The page has up-to-date data.
    ie. for file backed page: (in-memory data revision >= on-disk one)
 4 - DIRTY
-   page has been written to, hence contains new data
+   The page has been written to, hence contains new data.
    i.e. for file backed page: (in-memory data revision >  on-disk one)
 8 - WRITEBACK
-   page is being synced to disk
+   The page is being synced to disk.
 
 LRU related page flags
 ----------------------
 
 5 - LRU
-   page is in one of the LRU lists
+   The page is in one of the LRU lists.
 6 - ACTIVE
-   page is in the active LRU list
+   The page is in the active LRU list.
 18 - UNEVICTABLE
-   page is in the unevictable (non-)LRU list It is somehow pinned and
+   The page is in the unevictable (non-)LRU list It is somehow pinned and
    not a candidate for LRU page reclaims, e.g. ramfs pages,
-   shmctl(SHM_LOCK) and mlock() memory segments
+   shmctl(SHM_LOCK) and mlock() memory segments.
 2 - REFERENCED
-   page has been referenced since last LRU list enqueue/requeue
+   The page has been referenced since last LRU list enqueue/requeue.
 9 - RECLAIM
-   page will be reclaimed soon after its pageout IO completed
+   The page will be reclaimed soon after its pageout IO completed.
 11 - MMAP
-   a memory mapped page
+   A memory mapped page.
 12 - ANON
-   a memory mapped page that is not part of a file
+   A memory mapped page that is not part of a file.
 13 - SWAPCACHE
-   page is mapped to swap space, i.e. has an associated swap entry
+   The page is mapped to swap space, i.e. has an associated swap entry.
 14 - SWAPBACKED
-   page is backed by swap/RAM
+   The page is backed by swap/RAM.
 
 The page-types tool in the tools/vm directory can be used to query the
 above flags.
-- 
2.17.1