<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Sep 21, 2016 at 10:12 PM, ZhaoKang <span dir="ltr"><<a href="mailto:zhaokang@mail.tsinghua.edu.cn" target="_blank">zhaokang@mail.tsinghua.edu.cn</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US">Hello James,<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US"> </span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US">Yes, the failed VM's 'cat
/proc/sys/vm/overcommit_<wbr>memory' is exactly 2, but the correct VM's is also 2.
And I dump the memory and disk below:<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US"> </span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><b><span lang="EN-US" style="color:red">Failed one</span></b><span lang="EN-US">:<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">fangqing@[xhdengvm155043
kcc_case]$ cat /proc/sys/vm/overcommit_memory<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new";color:red">2<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new""> </span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">fangqing@[xhdengvm155043
kcc_case]$ top<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">top -
10:23:42 up 8 days, 11:12, 5 users, load average: 0.07, 0.02, 0.00<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">Tasks:
120 total, 1 running, 119 sleeping, 0
stopped, 0 zombie<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">Cpu(s):
1.2%us, 0.0%sy, 0.0%ni, 98.8%id, 0.0%wa, 0.0%hi,
0.0%si, 0.0%st<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">Mem:
<span style="color:red">5993176k</span> total, 1598600k used,
4394576k free, 245492k buffers<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">Swap:
4128760k total, 0k used,
4128760k free, 864412k cached<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new""> </span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">fangqing@[xhdengvm155043
kcc_case]$ df -h .<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">Filesystem
Size Used Avail Use% Mounted on<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">svmitfiler2-lif1:/Home/Home_<wbr>xbj/fangqing<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">
6.2T 4.7T 1.5T 76% /home/Fangqing<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><b><span lang="EN-US" style="color:red"> </span></b></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><b><span lang="EN-US" style="color:red">Correct one</span></b><span lang="EN-US" style="font-family:"courier new"">:<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">fangqing@[xhdvdieodvm102
local]$ cat /proc/sys/vm/overcommit_memory<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">2<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new""> </span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">fangqing@[xhdvdieodvm102
local]$ top<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">top -
10:16:52 up 36 days, 21:47, 50 users, load average: 2.51, 2.68, 2.70<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">Tasks:
357 total, 4 running, 351 sleeping, 1
stopped, 1 zombie<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">Cpu(s):
99.7%us, 0.3%sy, 0.0%ni, 0.0%id, 0.0%wa,
0.0%hi, 0.0%si, 0.0%st<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">Mem:
<span style="color:red">16436116k</span> total, 16347972k
used, 88144k free, 38592k buffers<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">Swap:
32767992k total, 2364888k used, 30403104k free, 14688384k cached<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new""> </span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">fangqing@[xhdvdieodvm102
kcc_case]$ df -h .<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">Filesystem
Size Used Avail Use% Mounted on<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">svmitfiler2-lif1:/Home/Home_<wbr>xbj/fangqing<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new"">
6.2T 4.7T 1.5T 76% /home/Fangqing<u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US" style="font-family:"courier new""> </span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US">So why?</span></p></blockquote><div>I frankly don't know.</div><div>On my box (Ubuntu 14.04) setting <span style="font-size:12.8px"> /proc/sys/vm/overcommit_</span><wbr style="font-size:12.8px"><span style="font-size:12.8px">memory to 2 does not cause the test to fail. </span></div><div><span style="font-size:12.8px">You should probably ask someone who knows more about the Linux Kernel. </span></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US"><u></u><u></u></span></p>
<p class="gmail-m_2778682287916482985MsoPlainText"><span lang="EN-US">Thanks a lot!<u></u><u></u></span></p><br>> -----原始邮件-----<br>> 发件人: "James Knight" <<a href="mailto:jyknight@google.com" target="_blank">jyknigh<wbr>t@google.com</a>><br>> 发送时间: 2016-09-22 11:23:07 (<wbr>星期四)<br>> 收件人: ZhaoKang <<a href="mailto:zhaokang@mail.tsinghua.edu.cn" target="_blank">zhaokang@<wbr>mail.tsinghua.edu.cn</a>>, "<wbr>ZhaoKang via cfe-dev" <<a href="mailto:cfe-dev@lists.llvm.org" target="_blank">cfe-<wbr>dev@lists.llvm.org</a>><br>> 抄送: "Kostya Serebryany" <<a href="mailto:kcc@google.com" target="_blank">kcc<wbr>@google.com</a>><br>> 主题: Re: [cfe-dev] Question <wbr>about Clang/LLVM <wbr>addresssanitizer<div class="gmail-HOEnZb"><div class="gmail-h5"><br>> <br>> <br>> > On Sep 20, 2016, at 9:47 <wbr>PM, ZhaoKang via cfe-dev <<a href="mailto:cfe-dev@lists.llvm.org" target="_blank">cfe-<wbr>dev@lists.llvm.org</a>> wrote:<br>> > <br>> > You mentioned that 'Some <wbr>global settings in the system <wbr>may for some reason reject <wbr>such huge mappings.'<br>> > And I want to know which <wbr>kinds of settings may have <wbr>this effect?<br>> <br>> cat /proc/sys/vm/overcommit_<wbr>memory on your system.<br>> <br>> The default value is 0, <wbr>which means allow overcommit <wbr>heuristically when it seems <wbr>likely to work. <br>> <br>> If, however, your system <wbr>has that set to 2 (which I'm <wbr>guessing it does), linux will <wbr>ignore the MAP_NORESERVE flag,<wbr> and *always* demands you <wbr>have enough ram and swap to <wbr>hold everything that might <wbr>ever possibly be written.<br>> <br>> In that case, either set it <wbr>back to 0, or else add 16TB <wbr>or so of swapspace to your <wbr>system.<br>> <br>> Almost nobody ever sets <wbr>that option to 2, because it'<wbr>s almost completely useless <wbr>to do so, and just breaks <wbr>stuff. :)<br><br><br><br></div></div></blockquote></div><br></div></div>