[Lustre-discuss] Facing issues in applying zero copy patch on rhel6.
Akam
azurelustre at gmail.com
Mon Apr 7 10:31:36 PDT 2014
Little more searching would give me this @ OFD landings -
https://jira.hpdd.intel.com/browse/LU-911
HTH
On Mon, Apr 7, 2014 at 8:48 PM, Parinay Kondekar <
parinay_kondekar at xyratex.com> wrote:
>
>
> On 7 April 2014 17:46, aayush agrawal <aayush.agrawal at calsoftinc.com>wrote:
>
>> Hi,
>>
>> Following are few questions which still remain unanswered:
>>
>>
>> 1. I am seeing that zero copy patch existed in lustre-2.1.2, In
>> lustre/kernel-patches/patches directory for rhel5. But it has been removed
>> in latest lustre 2.5.0. Is there any specific reason to remove it?
>>
>> Little searching gave me this - https://jira.hpdd.intel.com/browse/LU-535
> / http://review.whamcloud.com/#/c/1142/ .
>
>
>
>>
>> 1. If I am correct this code gets invoked from following location
>> from obdfilter(correct me if I am wrong):
>> 1. lustre/obdfilter/filter_io_26.c line
>> no:367
>> &
>> nbsp; &
>> nbsp;&nb sp; <snip>
>>
>> /* I only set the page to be constant only if it
>> * is mapped to a contiguous underlying disk
>> block(s).
>> * It will then make sure the corresponding device
>> * cache of raid5 will be overwritten by this
>> page.
>> * - jay */
>> if ((rw == OBD_BRW_WRITE) &&
>> (nblocks == blocks_per_page) &&
>>
>> mapping_cap_page_constant_write(inode->i_mapping))
>> SetPageConstant(page);
>>
>> </snip>
>>
>> 1. I want to use this zero copy patch in latest lustre 2.5.0(With
>> kernel linux-2.6.32-358.18.1.el6). I could port patch to this latest
>> kernel. But it looks like obdfilter module has been replaced in latest
>> kernel which used to invoke zero copy changes as mentioned in point 2. I
>> think its ofd module with which it got replaced(??). So latest lustre is
>> not able to invoke zero copy changes(for eg: setting/clearing PG_constant
>> etc.). Is there any different patch available for invoking these zero copy
>> changes?
>> 2. Can you also suggest which newly added module in lustre-2.5.0
>> would require these changes?
>>
>>
>> Thanks,
>> Aayush
>>
>>
>> On 4/7/2014 4:50 PM, aayush agrawal wrote:
>>
>> Hi,
>>
>> I got both the errors resolved. Looks like there was some issue with my
>> lustre build process itself.
>> So I think along with raid5-zerocopy-rhel6.patch, raid5-stats-rhel6.patch
>> was the only additional patch required.
>>
>> Thanks,
>> Aayush
>>
>> On 3/24/2014 8:40 PM, aayush agrawal wrote:
>>
>> Hi,
>>
>> I wanted to apply zero copy patch on rhel6 so I followed below steps:
>>
>>
>> 1. Downloaded lustre-2.1.2 and corresponding kernel rpm
>> (linux-2.6.32-220.17.1.el6). The OS I am using is CentOS 6.4.
>> 2. Applied kernel patches from lustre source code to kernel.
>> 3. Downloaded a zero copy patch for rhel6 from:
>> https://github.com/Xyratex/lustre-stable/blob/b_neo_1.4.0/lustre/kernel_patches/patches/raid5-zerocopy-rhel6.patch
>> 4. Applied this patch to above kernel.
>> 5. Then I tried to compile this kernel but it gives undefined symbol
>> errors for writes_zcopy and PageConstant.
>> 1. For writes_zcopy I found another patch on the same git hub
>> link:
>> https://github.com/Xyratex/lustre-stable/blob/b_neo_1.4.0/lustre/kernel_patches/patches/raid5-stats-rhel6.patch
>> .
>> 2. For PageConstant I couldn't find any patch to rectify this
>> error. Even I do not see usage of PG_Constant/SetPageConstant etc. in
>> raid5-zerocopy-rhel6.patch which I think is essential.
>> 6. So my questions are:
>> 1. I think few patches are missing here. As mentioned above one of
>> them would be raid5-stats-rhel6.patch please confirm.
>> 2. if confirmed, still there has to be at least one patch missing
>> (to include PageConstant use). Are there any other patches to be applied
>> before I apply raid5-stats-rhel6.patch and raid5-zerocopy-rhel6.patch.
>> 3. I am seeing that this zero copy patch existed in lustre-2.1.2,
>> In lustre/kernel-patches/patches directory for rhel5. But it has been
>> removed in latest lustre 2.5.0. Is there any specific reason to remove it.
>>
>> Thanks,
>> Aayush
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
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>>
>>
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--
cheers
Akam
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