From: Roland Dreier <rdreier-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
To: Alexander Schmidt
<alexs-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
Cc: of-ewg <ewg-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org>,
Linux RDMA <linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Hoang-Nam Nguyen
<hnguyen-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>,
Stefan Roscher
<stefan.roscher-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org>,
Joachim Fenkes <fenkes-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org>,
Christoph Raisch <raisch-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org>,
Alex Vainman
<alexonlists-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [RFC] libibverbs: ibv_fork_init() and libhugetlbfs
Date: Wed, 12 May 2010 09:40:16 -0700 [thread overview]
Message-ID: <adafx1xul8v.fsf@roland-alpha.cisco.com> (raw)
In-Reply-To: <20100507121936.283a18c6@alex-laptop> (Alexander Schmidt's message of "Fri, 7 May 2010 12:19:36 +0200")
> * added get_huge_page_size() to read the huge page size from
> /proc/meminfo. This is done at ibv_fork_init() time.
That doesn't work on systems that have multiple huge page sizes (eg
powerpc). You can compare the code to get the size in libhugetlbfs.
Also I think the munging through /proc/pid/maps doesn't really work.
First of all, essentially grepping for libhugetlbfs is not robust as I
mentioned -- this will break in the same way for apps using huge pages
directly. And while it is nice to be able to tell if a range came from
libhugetlbfs, I think there may be some bad performance impact from
reading /proc/pid/maps line-by-line. (And by the way, as a trivial
optimization, it would make sense to me to check the address of each map
before doing the strstr).
- R.
--
Roland Dreier <rolandd-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org> || For corporate legal information go to:
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next prev parent reply other threads:[~2010-05-12 16:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-06 7:39 [RFC] libibverbs: ibv_fork_init() and libhugetlbfs Alexander Schmidt
2010-05-06 20:55 ` Roland Dreier
[not found] ` <adavdb092d8.fsf-BjVyx320WGW9gfZ95n9DRSW4+XlvGpQz@public.gmane.org>
2010-05-07 10:19 ` Alexander Schmidt
2010-05-12 16:40 ` Roland Dreier [this message]
[not found] ` <adafx1xul8v.fsf-BjVyx320WGW9gfZ95n9DRSW4+XlvGpQz@public.gmane.org>
2010-05-18 11:04 ` [ewg] " Stefan Roscher
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