From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sog-mx-1.v43.ch3.sourceforge.com ([172.29.43.191] helo=mx.sourceforge.net) by sfs-ml-1.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1XswLX-0007gc-EG for ltp-list@lists.sourceforge.net; Mon, 24 Nov 2014 16:18:39 +0000 Received: from e8.ny.us.ibm.com ([32.97.182.138]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.76) id 1XswLV-0005GM-R4 for ltp-list@lists.sourceforge.net; Mon, 24 Nov 2014 16:18:39 +0000 Received: from /spool/local by e8.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 24 Nov 2014 11:18:32 -0500 Received: from b01cxnp23033.gho.pok.ibm.com (b01cxnp23033.gho.pok.ibm.com [9.57.198.28]) by d01dlp03.pok.ibm.com (Postfix) with ESMTP id AACC9C90048 for ; Mon, 24 Nov 2014 11:10:32 -0500 (EST) Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by b01cxnp23033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id sAOGISTB24379492 for ; Mon, 24 Nov 2014 16:18:28 GMT Received: from d01av04.pok.ibm.com (localhost [127.0.0.1]) by d01av04.pok.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id sAOGISqx006302 for ; Mon, 24 Nov 2014 11:18:28 -0500 Received: from oc3602201088.ibm.com (sig-9-65-68-77.mts.ibm.com [9.65.68.77]) by d01av04.pok.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id sAOGIRDf006126 for ; Mon, 24 Nov 2014 11:18:27 -0500 Message-ID: <54735A52.8020909@linux.vnet.ibm.com> Date: Mon, 24 Nov 2014 10:18:26 -0600 From: Meenakshi Sripal MIME-Version: 1.0 Subject: [LTP] proposed patch to fix ltp max_map_count test failure on ppc List-Id: Linux Test Project General Discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============3737634961956696956==" Errors-To: ltp-list-bounces@lists.sourceforge.net To: ltp-list@lists.sourceforge.net This is a multi-part message in MIME format. --===============3737634961956696956== Content-Type: multipart/alternative; boundary="------------070701000909030404070906" This is a multi-part message in MIME format. --------------070701000909030404070906 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Ltp-list: *Description: *Base ltp testcase max_map_count is failing on ppc arch kernel: 3.10.0-123.9.3 Here is the proposed patch to be submitted upstream: Patch: --- ltp-full-20140828.orig/testcases/kernel/mem/tunable/max_map_count.c 2014-11-11 11:13:39.811776626 -0600 +++ ltp-full-20140828/testcases/kernel/mem/tunable/max_map_count.c 2014-11-11 11:14:05.650945873 -0600 @@ -231,7 +231,7 @@ static void max_map_count_test(void) * is the mm failure point at the time of * writing this COMMENT! */ - if (map_count == (max_maps + 1)) + if (map_count <= (max_maps + 1)) tst_resm(TPASS, "%ld map entries in total " "as expected.", max_maps); else * *Although according to the description of the test case "map_count <= max_map_count" is valid, it is implemented as "map_count == (max_map_count + 1)" in the code. We can say that the test case can be passed for "map_count <= (max_map_count + 1)" because, MAP_FAILED can be triggered NOT ONLY when max_map_count is reached, but also when the kernel is running out of memory. IN THIS TESTCASE KERNEL RUNS OUT OF MEMORY BECAUSE THE PAGE SIZE IS HUGE. Kernel allocates mapped area for each process, as entered in the file /proc/[pid]/maps, as multiples of pagesize. Hence when the page size is huge, the kernel runs out of memory (aligned addresses in this case) even before max_map_count is reached. Please find below test results suggesting that it is because of the big page size that MAP_FAILED is triggered. Note that the amount of free memory is almost the same on both the systems. IA32: kernel: 3.10.0-123.9.3 # getconf PAGESIZE 4096 # free -g total used free shared buffers cached Mem: 23 1 22 0 0 0 -/+ buffers/cache: 0 22 Swap: 0 0 0 # cat /proc/sys/vm/max_map_count 65530 # ./max_map_count max_map_count 0 TINFO : set overcommit_memory to 2 max_map_count 0 TINFO : set max_map_count to 64 max_map_count 1 TPASS : 64 map entries in total as expected. max_map_count 0 TINFO : set max_map_count to 256 max_map_count 2 TPASS : 256 map entries in total as expected. max_map_count 0 TINFO : set max_map_count to 1024 max_map_count 3 TPASS : 1024 map entries in total as expected. max_map_count 0 TINFO : set max_map_count to 4096 max_map_count 4 TPASS : 4096 map entries in total as expected. max_map_count 0 TINFO : set max_map_count to 16384 max_map_count 5 TPASS : 16384 map entries in total as expected. max_map_count 0 TINFO : set max_map_count to 65536 max_map_count 6 TPASS : 65536 map entries in total as expected. max_map_count 0 TINFO : set overcommit_memory to 0 max_map_count 0 TINFO : set max_map_count to 65530 PPC: kernel: 3.10.0-123.9.3 -bash-4.2# getconf PAGESIZE 65536 -bash-4.2# free -g total used free shared buffers cached Mem: 19 0 18 0 0 0 -/+ buffers/cache: 0 19 Swap: 7 0 7 -bash-4.2# cat /proc/sys/vm/max_map_count 65530 -bash-4.2# cd /opt/fiv/ltp/testcases/bin/ -bash-4.2# ./max_map_count max_map_count 0 TINFO : set overcommit_memory to 2 max_map_count 0 TINFO : set max_map_count to 64 max_map_count 1 TPASS : 64 map entries in total as expected. max_map_count 0 TINFO : set max_map_count to 256 max_map_count 2 TPASS : 256 map entries in total as expected. max_map_count 0 TINFO : set max_map_count to 1024 max_map_count 3 TPASS : 1024 map entries in total as expected. max_map_count 0 TINFO : set max_map_count to 4096 max_map_count 4 TPASS : 4096 map entries in total as expected. max_map_count 0 TINFO : set max_map_count to 16384 max_map_count 5 TPASS : 16384 map entries in total as expected. max_map_count 0 TINFO : set max_map_count to 65536 max_map_count 6 TFAIL : max_map_count.c:239: 65489 map entries in total, but expected 65536 entries max_map_count 0 TINFO : set overcommit_memory to 0 max_map_count 0 TINFO : set max_map_count to 65530 After the patch is applied, the test passes: -bash-4.2# ./max_map_count max_map_count 0 TINFO : set overcommit_memory to 2 max_map_count 0 TINFO : set max_map_count to 64 max_map_count 1 TPASS : 64 map entries in total as expected. max_map_count 0 TINFO : set max_map_count to 256 max_map_count 2 TPASS : 256 map entries in total as expected. max_map_count 0 TINFO : set max_map_count to 1024 max_map_count 3 TPASS : 1024 map entries in total as expected. max_map_count 0 TINFO : set max_map_count to 4096 max_map_count 4 TPASS : 4096 map entries in total as expected. max_map_count 0 TINFO : set max_map_count to 16384 max_map_count 5 TPASS : 16384 map entries in total as expected. max_map_count 0 TINFO : set max_map_count to 65536 max_map_count 6 TPASS : 65536 map entries in total as expected. max_map_count 0 TINFO : set overcommit_memory to 0 max_map_count 0 TINFO : set max_map_count to 65530 *************************** Meenakshi Sripal Linux Technology Center - Embedded Linux --------------070701000909030404070906 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Ltp-list:

Description: Base ltp testcase max_map_count is failing on ppc arch

kernel: 3.10.0-123.9.3

Here is the proposed patch to be submitted upstream:
Patch:
--- ltp-full-20140828.orig/testcases/kernel/mem/tunable/max_map_count.c    2014-11-11 11:13:39.811776626 -0600
+++ ltp-full-20140828/testcases/kernel/mem/tunable/max_map_count.c    2014-11-11 11:14:05.650945873 -0600
@@ -231,7 +231,7 @@ static void max_map_count_test(void)
         * is the mm failure point at the time of
         * writing this COMMENT!
        */
-        if (map_count == (max_maps + 1))
+        if (map_count <= (max_maps + 1))
            tst_resm(TPASS, "%ld map entries in total "
                 "as expected.", max_maps);
        else


Although according to the description of the test case "map_count <= max_map_count" is valid, it is implemented as "map_count == (max_map_count + 1)" in the code.

We can say that the test case can be passed for "map_count <= (max_map_count + 1)"  because, MAP_FAILED can be triggered NOT ONLY when max_map_count is reached, but also when the kernel is running out of memory. IN THIS TESTCASE KERNEL RUNS OUT OF MEMORY BECAUSE THE PAGE SIZE IS HUGE.
Kernel allocates mapped area for each process, as entered in the file /proc/[pid]/maps, as multiples of pagesize.
Hence when the page size is huge, the kernel runs out of memory (aligned addresses in this case) even before max_map_count is reached.

Please find below test results suggesting that it is because of the big page size that MAP_FAILED is triggered.
Note that the amount of free memory is almost the same on both the systems.

IA32:

kernel: 3.10.0-123.9.3

# getconf PAGESIZE
4096
# free -g
             total       used       free     shared    buffers     cached
Mem:            23          1         22          0          0          0
-/+ buffers/cache:          0         22
Swap:            0          0          0
# cat /proc/sys/vm/max_map_count
65530

# ./max_map_count
max_map_count    0  TINFO  :  set overcommit_memory to 2
max_map_count    0  TINFO  :  set max_map_count to 64
max_map_count    1  TPASS  :  64 map entries in total as expected.
max_map_count    0  TINFO  :  set max_map_count to 256
max_map_count    2  TPASS  :  256 map entries in total as expected.
max_map_count    0  TINFO  :  set max_map_count to 1024
max_map_count    3  TPASS  :  1024 map entries in total as expected.
max_map_count    0  TINFO  :  set max_map_count to 4096
max_map_count    4  TPASS  :  4096 map entries in total as expected.
max_map_count    0  TINFO  :  set max_map_count to 16384
max_map_count    5  TPASS  :  16384 map entries in total as expected.
max_map_count    0  TINFO  :  set max_map_count to 65536
max_map_count    6  TPASS  :  65536 map entries in total as expected.
max_map_count    0  TINFO  :  set overcommit_memory to 0
max_map_count    0  TINFO  :  set max_map_count to 65530
PPC:

kernel: 3.10.0-123.9.3

-bash-4.2# getconf PAGESIZE
65536
-bash-4.2# free -g
             total       used       free     shared    buffers     cached
Mem:            19          0         18          0          0          0
-/+ buffers/cache:          0         19
Swap:            7          0          7
-bash-4.2# cat /proc/sys/vm/max_map_count
65530

-bash-4.2# cd /opt/fiv/ltp/testcases/bin/
-bash-4.2# ./max_map_count
max_map_count    0  TINFO  :  set overcommit_memory to 2
max_map_count    0  TINFO  :  set max_map_count to 64
max_map_count    1  TPASS  :  64 map entries in total as expected.
max_map_count    0  TINFO  :  set max_map_count to 256
max_map_count    2  TPASS  :  256 map entries in total as expected.
max_map_count    0  TINFO  :  set max_map_count to 1024
max_map_count    3  TPASS  :  1024 map entries in total as expected.
max_map_count    0  TINFO  :  set max_map_count to 4096
max_map_count    4  TPASS  :  4096 map entries in total as expected.
max_map_count    0  TINFO  :  set max_map_count to 16384
max_map_count    5  TPASS  :  16384 map entries in total as expected.
max_map_count    0  TINFO  :  set max_map_count to 65536
max_map_count    6  TFAIL  :  max_map_count.c:239: 65489 map entries in total, but expected 65536 entries
max_map_count    0  TINFO  :  set overcommit_memory to 0
max_map_count    0  TINFO  :  set max_map_count to 65530

After the patch is applied, the test passes:
-bash-4.2# ./max_map_count
max_map_count    0  TINFO  :  set overcommit_memory to 2
max_map_count    0  TINFO  :  set max_map_count to 64
max_map_count    1  TPASS  :  64 map entries in total as expected.
max_map_count    0  TINFO  :  set max_map_count to 256
max_map_count    2  TPASS  :  256 map entries in total as expected.
max_map_count    0  TINFO  :  set max_map_count to 1024
max_map_count    3  TPASS  :  1024 map entries in total as expected.
max_map_count    0  TINFO  :  set max_map_count to 4096
max_map_count    4  TPASS  :  4096 map entries in total as expected.
max_map_count    0  TINFO  :  set max_map_count to 16384
max_map_count    5  TPASS  :  16384 map entries in total as expected.
max_map_count    0  TINFO  :  set max_map_count to 65536
max_map_count    6  TPASS  :  65536 map entries in total as expected.
max_map_count    0  TINFO  :  set overcommit_memory to 0
max_map_count    0  TINFO  :  set max_map_count to 65530

***************************
Meenakshi Sripal
Linux Technology Center - Embedded Linux

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