<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <meta name="Generator" content="Microsoft Word 15 (filtered medium)"> <style></style> </head> <body lang="EN-IE" link="#0563C1" vlink="#954F72" style="word-wrap:break-word"> <div class="WordSection1"> <p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New";mso-fareast-language:EN-US"><o:p> </o:p></span></p> <p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New";mso-fareast-language:EN-US">I may be incorrect, but is it not simply the case, that when using the no-huge parameter that MAP_HUGETLB is omitted from flags?<o:p></o:p></span></p> <p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New";mso-fareast-language:EN-US"><o:p> </o:p></span></p> <p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New";mso-fareast-language:EN-US">Ray K<o:p></o:p></span></p> <p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New";mso-fareast-language:EN-US"><o:p> </o:p></span></p> <div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm"> <p class="MsoNormal" style="margin-left:36.0pt"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> Nick Tian <nick.tian@longsailingsemi.com> <br> <b>Sent:</b> Tuesday 9 August 2022 03:55<br> <b>To:</b> users@dpdk.org<br> <b>Subject:</b> About memory coherency<o:p></o:p></span></p> </div> <p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p> <div id="mailbox-conversation"> <div> <blockquote style="margin-top:5.0pt;margin-bottom:5.0pt"> <div id="mailbox-conversation"> <div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black">Hi<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black">I am confusing about the "no-huge" option of DPDK 21.11.<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black">The dpdk usage said: --no-huge:Use malloc instead of hugetlbfs.<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black">But when I check the EAL source code, I found some code piece like this:<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black">It's look like "no-huge" option will lead dpdk use memfd_create-->ftruncate-->mmap to reserve memory<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black">and then provide to application with rte_malloc.<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black">Am I right?<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black">If so, what the "malloc" in "use malloc instead of hugelbfs" refer to?<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black"><o:p> </o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black">EAL_memory.c<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black">static int eal_legacy_hugepage_init(void){<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black">....<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black"> if (internal_conf->no_hugetlbfs) {<br> ....<br> #ifdef MEMFD_SUPPORTED<br> /* create a memfd and store it in the segment fd table */<br> memfd = memfd_create("nohuge", 0);<br> ......<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black"> /* we got an fd - now resize it */<br> if (ftruncate(memfd, internal_conf->memory) < 0) {<br> .....<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black"> fd = memfd;<br> flags = MAP_SHARED; }<br> ....<br> prealloc_addr = msl->base_va;<br> addr = mmap(prealloc_addr, mem_sz, PROT_READ | PROT_WRITE,<br> <span style="background:yellow;mso-highlight:yellow">flags</span> | MAP_FIXED, fd, 0);<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black">...<o:p></o:p></span></p> </div> <div> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black"><o:p> </o:p></span></p> </div> <div> <div id="mailbox-conversation"> <p class="MsoNormal" style="margin-left:36.0pt"><span style="font-size:10.5pt;font-family:"Microsoft YaHei",sans-serif;color:black"><o:p> </o:p></span></p> </div> </div> </div> </div> </blockquote> </div> </div> </div> </body> </html>