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<div class="moz-cite-prefix">Hi Parinay,<br>
<br>
Thanks for your help. I went through that link and it partly
answers my first question.<br>
I can see that the patch in the link you sent is for
linux-2.6.32-279.14.1.el6(lustre-2.1.4), but this patch is not
included in upstream released lustre-2.1.4.<br>
So my next two questions still remain unanswered.<br>
<br>
Thanks,<br>
Aayush.<br>
<br>
On 4/7/2014 8:48 PM, Parinay Kondekar wrote:<br>
</div>
<blockquote
cite="mid:CAB+_9GpsVo-6OU14Sb0E-=d=9cEQDQ-mSNKj3ibsHRs4A1C+Zw@mail.gmail.com"
type="cite">
<div dir="ltr">
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On 7 April 2014 17:46, aayush agrawal
<span dir="ltr"><<a moz-do-not-send="true"
href="mailto:aayush.agrawal@calsoftinc.com"
target="_blank">aayush.agrawal@calsoftinc.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div>Hi,<br>
<br>
Following are few questions which still remain
unanswered:<br>
<br>
<ol>
<li>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?</li>
</ol>
</div>
</div>
</blockquote>
Little searching gave me this - <a moz-do-not-send="true"
href="https://jira.hpdd.intel.com/browse/LU-535">https://jira.hpdd.intel.com/browse/LU-535</a> / <a
moz-do-not-send="true"
href="http://review.whamcloud.com/#/c/1142/">http://review.whamcloud.com/#/c/1142/</a> .
<div>
<br>
</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div>
<ol>
<li>If I am correct this code gets invoked from
following location from obdfilter(correct me if I
am wrong):</li>
<ol>
<li>lustre/obdfilter/filter_io_26.c line
no:367 &
nbsp;
&
nbsp; &n
bsp; &
nbsp;&nb
sp;
<snip><br>
</li>
</ol>
</ol>
<p> /* I only set the page to
be constant only if it<br>
* is mapped to a contiguous
underlying disk block(s).<br>
* It will then make sure
the corresponding device<br>
* cache of raid5 will be
overwritten by this page.<br>
* - jay */<br>
if ((rw == OBD_BRW_WRITE)
&&<br>
(nblocks ==
blocks_per_page) &&<br>
mapping_cap_page_constant_write(inode->i_mapping))<br>
SetPageConstant(page);<br>
<br>
</snip><br>
</p>
<ol>
<li>I want to use this zero copy patch in latest
lustre 2.5.0(With kernel <font face="Times New
Roman, serif"><font size="3">linux-2.6.32-358.18.1.el6</font></font>).
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?</li>
<li>Can you also suggest which newly added module in
lustre-2.5.0 would require these changes?</li>
</ol>
<br>
Thanks,<br>
Aayush
<div class=""><br>
<br>
On 4/7/2014 4:50 PM, aayush agrawal wrote:<br>
</div>
</div>
<div class="">
<blockquote type="cite">
<div>Hi,<br>
<br>
I got both the errors resolved. Looks like there
was some issue with my lustre build process
itself.<br>
So I think along with raid5-zerocopy-rhel6.patch,
raid5-stats-rhel6.patch was the only additional
patch required.<br>
<br>
Thanks,<br>
Aayush<br>
<br>
On 3/24/2014 8:40 PM, aayush agrawal wrote:<br>
</div>
<blockquote type="cite"> Hi,<br>
<br>
I wanted to apply zero copy patch on rhel6 so I
followed below steps:<br>
<br>
<ol>
<li>Downloaded <font face="Times New Roman,
serif"><font size="3">lustre-2.1.2 and
corresponding kernel rpm</font></font><font
face="Times New Roman, serif"><font size="3">(linux-2.6.32-220.17.1.el6</font></font>).
The OS I am using is CentOS 6.4.</li>
<li>Applied kernel patches from lustre source
code to kernel.</li>
<li>Downloaded a zero copy patch for rhel6 from:
<a moz-do-not-send="true"
href="https://github.com/Xyratex/lustre-stable/blob/b_neo_1.4.0/lustre/kernel_patches/patches/raid5-zerocopy-rhel6.patch"
target="_blank">https://github.com/Xyratex/lustre-stable/blob/b_neo_1.4.0/lustre/kernel_patches/patches/raid5-zerocopy-rhel6.patch</a></li>
<li>Applied this patch to above kernel.</li>
<li><font face="Times New Roman, serif"><font
size="3">Then I tried to compile this
kernel </font></font> but it gives
undefined symbol errors for writes_zcopy and
PageConstant.</li>
<ol>
<li>For writes_zcopy I found another patch on
the same git hub link: <a
moz-do-not-send="true"
href="https://github.com/Xyratex/lustre-stable/blob/b_neo_1.4.0/lustre/kernel_patches/patches/raid5-stats-rhel6.patch"
target="_blank">https://github.com/Xyratex/lustre-stable/blob/b_neo_1.4.0/lustre/kernel_patches/patches/raid5-stats-rhel6.patch</a>.</li>
<li>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. <br>
</li>
</ol>
<li>So my questions are:</li>
<ol>
<li>I think few patches are missing here. As
mentioned above one of them would be
raid5-stats-rhel6.patch please confirm.</li>
<li>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.</li>
<li>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.</li>
</ol>
</ol>
<p>Thanks,<br>
Aayush<br>
</p>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
</blockquote>
<br>
</blockquote>
<br>
</div>
</div>
<br>
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</blockquote>
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