tools/vm/page_owner_sort.c: support for multi-value selection in single argument

When viewing page owner information, we may want to select blocks whose
PID/TGID/TASK_COMM_NAME appears in a user-specified list for data analysis
and aggregation.  But currently page_owner_sort only supports selecting
blocks associated with only one specified PID/TGID/TASK_COMM_NAME.

Therefore, following adjustments are made to fix the problem:

1. Enhance selecting function to support the selection of multiple
   PIDs/TGIDs/TASK_COMM_NAMEs.

The enhanced usages are as follows:

--pid <pidlist>         Select by pid. This selects the blocks whose PID
                        numbers appear in <pidlist>.
--tgid <tgidlist>       Select by tgid. This selects the blocks whose
                        TGID numbers appear in <tgidlist>.
--name <cmdlist>        Select by task command name. This selects the
                        blocks whose task command name appear in <cmdlist>.

Where <pidlist>, <tgidlist>, <cmdlist> are single arguments in the form of
a comma-separated list,which offers a way to specify individual selecting
rules.

For example, if you want to select blocks whose tgids are 1, 2 or 3, you
have to use 4 commands as follows:

        ./page_owner_sort <input> <output1> --tgid=1
        ./page_owner_sort <input> <output2> --tgid=2
        ./page_owner_sort <input> <output3> --tgid=3
        cat <output1> <output2> <output3> > <output>

With this patch, you can use only 1 command to obtain the same result as
above:

        ./page_owner_sort <input> <output1> --tgid=1,2,3

2. Update explanations of --pid, --tgid and --name in the function
   usage() and the document(Documents/vm/page_owner.rst).

This work is coauthored by
        Yixuan Cao
        Shenghong Han
        Yinan Zhang
        Chongxi Zhao
        Yuhong Feng
        Yongqiang Liu

Link: https://lkml.kernel.org/r/20220401024856.767-2-yejiajian2018@email.szu.edu.cn
Signed-off-by: Jiajian Ye <yejiajian2018@email.szu.edu.cn>
Cc: Chongxi Zhao <zhaochongxi2019@email.szu.edu.cn>
Cc: Shenghong Han <hanshenghong2019@email.szu.edu.cn>
Cc: Yinan Zhang <zhangyinan2019@email.szu.edu.cn>
Cc: Yixuan Cao <caoyixuan2019@email.szu.edu.cn>
Cc: Yongqiang Liu <liuyongqiang13@huawei.com>
Cc: Yuhong Feng <yuhongf@szu.edu.cn>
Cc: Haowen Bai <baihaowen@meizu.com>
Cc: Sean Anderson <seanga2@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 15 insertions, 5 deletions

diff --git a/Documentation/vm/page_owner.rst b/Documentation/vm/page_owner.rst
index 7e0c3f574e78..3102f91d635c 100644
--- a/Documentation/vm/page_owner.rst
+++ b/Documentation/vm/page_owner.rst
@@ -129,7 +129,6 @@ Usage
 				Specify culling rules.Culling syntax is key[,key[,...]].Choose a
 				multi-letter key from the **STANDARD FORMAT SPECIFIERS** section.
 
-
 		<rules> is a single argument in the form of a comma-separated list,
 		which offers a way to specify individual culling rules.  The recognized
 		keywords are described in the **STANDARD FORMAT SPECIFIERS** section below.
@@ -137,7 +136,6 @@ Usage
 		the STANDARD SORT KEYS section below. Mixed use of abbreviated and
 		complete-form of keys is allowed.
 
-
 		Examples:
 				./page_owner_sort <input> <output> --cull=stacktrace
 				./page_owner_sort <input> <output> --cull=st,pid,name
@@ -147,9 +145,21 @@ Usage
 		-f		Filter out the information of blocks whose memory has been released.
 
 	Select:
-		--pid <PID>		Select by pid.
-		--tgid <TGID>		Select by tgid.
-		--name <command>	Select by task command name.
+		--pid <pidlist>		Select by pid. This selects the blocks whose process ID
+					numbers appear in <pidlist>.
+		--tgid <tgidlist>	Select by tgid. This selects the blocks whose thread
+					group ID numbers appear in <tgidlist>.
+		--name <cmdlist>	Select by task command name. This selects the blocks whose
+					task command name appear in <cmdlist>.
+
+		<pidlist>, <tgidlist>, <cmdlist> are single arguments in the form of a comma-separated list,
+		which offers a way to specify individual selecting rules.
+
+
+		Examples:
+				./page_owner_sort <input> <output> --pid=1
+				./page_owner_sort <input> <output> --tgid=1,2,3
+				./page_owner_sort <input> <output> --name name1,name2
 
 STANDARD FORMAT SPECIFIERS
 ==========================