DPDK patches and discussions
 help / color / mirror / Atom feed
From: Tetsuya Mukawa <mukawa@igel.co.jp>
To: "Xie, Huawei" <huawei.xie@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] vhost-user technical isssues
Date: Mon, 17 Nov 2014 15:14:01 +0900	[thread overview]
Message-ID: <54699229.8010603@igel.co.jp> (raw)
In-Reply-To: <C37D651A908B024F974696C65296B57B0F303CAA@SHSMSX101.ccr.corp.intel.com>

Hi Xie,

(2014/11/14 19:59), Xie, Huawei wrote:
> I tested with latest qemu(with offset fix) in vhost app(not with test case), unmap succeeds only when the size is aligned to 1GB(hugepage size).
I appreciate for your testing.

> Another important thing is  could we do mmap(0, region[i].memory_size, PROT_XX, mmap_offset) rather than with offset 0? With the region above 4GB, we will waste 4GB address space. Or we at least need to round down offset to nearest 1GB, and round up memory size to upper 1GB, to save some address space waste.
>
> Anyway, this is ugly. Kernel doesn't take care of us, do those alignment for us automatically.
>

It seems 'offset' also should be aligned by hugepage size also.
But it might be a specification of mmap. Manpage of mmap says 'offset'
should be aligned by sysconf(_SC_PAGE_SIZE).
If the target file is on hugetlbfs, I guess hugepage size is used as
alignment size.

Thanks,
Tetsuya

  reply	other threads:[~2014-11-17  6:03 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-11 21:37 Xie, Huawei
2014-11-12  4:12 ` Tetsuya Mukawa
2014-11-13  6:30   ` Linhaifeng
2014-11-14  2:30     ` Tetsuya Mukawa
2014-11-14  3:13       ` Linhaifeng
2014-11-14  3:40         ` Tetsuya Mukawa
2014-11-14  4:05           ` Tetsuya Mukawa
2014-11-14  4:42           ` Linhaifeng
2014-11-14  5:12             ` Tetsuya Mukawa
2014-11-14  5:30               ` Linhaifeng
2014-11-14  6:57                 ` Tetsuya Mukawa
2014-11-14 10:59                   ` Xie, Huawei
2014-11-17  6:14                     ` Tetsuya Mukawa [this message]
2014-11-14  0:22   ` Xie, Huawei
2014-11-14  2:52     ` Tetsuya Mukawa
2014-11-15  1:42       ` Xie, Huawei
2014-11-13  6:12 ` Linhaifeng
2014-11-13  6:27 ` Linhaifeng
2014-11-14  1:28   ` Xie, Huawei
2014-11-14  2:24     ` Linhaifeng
2014-11-14  2:35       ` Tetsuya Mukawa
2014-11-14  6:24       ` Xie, Huawei

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=54699229.8010603@igel.co.jp \
    --to=mukawa@igel.co.jp \
    --cc=dev@dpdk.org \
    --cc=huawei.xie@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).