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RE: [PATCH] Kprobe:multi kprobe posthandler for booster


Andrew,

This patch solves minor performance problem, it is based on http://marc.theaimsgroup.com/?l=linux-kernel&m=114104159911612&w=4, Kprobe-booster can take effect only when post_handler is NULL, however when there are multiple kprobes on the same probepoint, post_handler of aggr_kprobe will be set. This patch modifies this, post_handler of aggr_kprobe will be set only if there exist one kprobe whose post_hander is not NULL.

kprobe-cleanup-for-vm_mask-judgement.patch is irrelative with booster kprobe.

Thanks
bibo,mao

>-----Original Message-----
>From: Andrew Morton [mailto:akpm@osdl.org]
>Sent: 2006年4月27日 5:55
>To: Mao, Bibo
>Cc: systemtap@sources.redhat.com
>Subject: Re: [PATCH] Kprobe:multi kprobe posthandler for booster
>
>"mao, bibo" <bibo.mao@intel.com> wrote:
>>
>>   If there are multi kprobes on the same probepoint, there
>> will be one extra aggr_kprobe on the head of kprobe list.
>> The aggr_kprobe has aggr_post_handler/aggr_break_handler
>> whether the other kprobe post_hander/break_handler is NULL
>> or not. This patch modifies this, only when there is one or
>> more kprobe in the list whose post_handler is not NULL,
>> post_handler of aggr_kprobe will be set as aggr_post_handler.
>
>OK...  But you didn't provide me with sufficient information with which I
>can gauge the seriousness of this problem.  Show-stopper bug?  Minor
>performance problem?  Hard to tell, and I do need that information to be
>able to judge whether patches should do into -rc or into the next kernel
>cycle, as well as being backported into -stable.
>
>I currently have four patches:
>
>kprobe-boost-2byte-opcodes-on-i386.patch
>kprobe-fix-resume-execution-on-i386.patch
>kprobemulti-kprobe-posthandler-for-booster.patch
>kprobe-cleanup-for-vm_mask-judgement.patch
>
>I _think_ the first two are 2.6.17 material and the latter two are 2.6.18
>material.  Could others please comment?


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