From: Masami Hiramatsu <mhiramat@redhat.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
lkml <linux-kernel@vger.kernel.org>,
systemtap <systemtap@sources.redhat.com>,
DLE <dle-develop@lists.sourceforge.net>,
Jim Keniston <jkenisto@us.ibm.com>
Subject: Re: [PATCH -tip 3/3] kprobes: cleanup: use list instead of hlist for insn_pages
Date: Tue, 30 Jun 2009 17:47:48 -0400 [thread overview]
Message-ID: <4A4A8804.1040004@redhat.com> (raw)
In-Reply-To: <20090630212512.GA10831@elte.hu>
Ingo Molnar wrote:
> * Masami Hiramatsu <mhiramat@redhat.com> wrote:
>
>> Use struct list instead of struct hlist for managing insn_pages,
>> because insn_pages doesn't use hash table.
>
>> struct kprobe_insn_page {
>> - struct hlist_node hlist;
>> + struct list_head list;
>
> Hm, you know that this increases the size of kprobe_insn_page by 4/8
> bytes, right?
Sure, that will increase size.
> hlists are not just used for hashes - but also when we want a more
> compact / smaller list head.
Oh, I thought hlists are used for hash tables...
>
> How many kprobe_insn_page's can be allocated in the system,
> maximally?
It's depends on how many probes you will use, but logically,
1 kprobe_insn_pages is allocated per 4096/16 = 256 probes.
So, if you use 25,600 probes on your system, memory
consumption will increase 400/800 bytes.
Thank you,
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com
next prev parent reply other threads:[~2009-06-30 21:45 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-30 21:07 [PATCH -tip 0/3] kprobes: trivial bugfixes and cleanup Masami Hiramatsu
2009-06-30 21:08 ` [PATCH -tip 1/3] kprobes: fix kprobe selftest configuration dependency Masami Hiramatsu
2009-06-30 21:39 ` [tip:tracing/urgent] kprobes: Fix " tip-bot for Masami Hiramatsu
2009-06-30 21:08 ` [PATCH -tip 2/3] kprobes: no need to unlock kprobe_insn_mutex Masami Hiramatsu
2009-06-30 21:40 ` [tip:tracing/urgent] kprobes: No " tip-bot for Masami Hiramatsu
2009-07-01 8:47 ` [tip:tracing/core] " tip-bot for Masami Hiramatsu
2009-06-30 21:08 ` [PATCH -tip 3/3] kprobes: cleanup: use list instead of hlist for insn_pages Masami Hiramatsu
2009-06-30 21:25 ` Ingo Molnar
2009-06-30 21:47 ` Masami Hiramatsu [this message]
2009-06-30 21:50 ` Ingo Molnar
2009-06-30 23:12 ` Masami Hiramatsu
2009-06-30 23:18 ` Ingo Molnar
2009-06-30 23:27 ` [tip:tracing/core] kprobes: Clean up insn_pages by using list instead of hlist tip-bot for Masami Hiramatsu
2009-07-01 8:47 ` tip-bot for Masami Hiramatsu
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