Whamcloud Community JIRA

Whamcloud Community JIRA https://jira.whamcloud.com This file is an XML representation of an issue en-us

9.4.14

940014

05-12-2023

[LU-15619] Reduce size of cl_page and associated structures https://jira.whamcloud.com/browse/LU-15619 Lustre <p>cl_page and its associated structures are allocated for every page, but can be shrunk down by removing unnecessary structure members.</p> LU-15619

Reduce size of cl_page and associated structures

Improvement Minor Resolved Fixed Patrick Farrell Patrick Farrell Fri, 4 Mar 2022 21:47:57 +0000 Wed, 6 Sep 2023 13:11:29 +0000 Wed, 6 Sep 2023 13:11:29 +0000 Lustre 2.16.0 0 4 <p>"Patrick Farrell <pfarrell@whamcloud.com>" uploaded a new patch: <a href="https://review.whamcloud.com/46712" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/46712</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-15619" title="Reduce size of cl_page and associated structures" class="issue-link" data-issue-key="LU-15619"><del>LU-15619</del></a> osc: Remove submit time<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: 019e37365401a034f41cbbdfb89c7a2930ee2890</p> <p>"Patrick Farrell <pfarrell@whamcloud.com>" uploaded a new patch: <a href="https://review.whamcloud.com/46713" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/46713</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-15619" title="Reduce size of cl_page and associated structures" class="issue-link" data-issue-key="LU-15619"><del>LU-15619</del></a> osc: Remove oap_magic<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: c90ea3a92d8ca414768d3e9b5150405cc4a3592c</p> <p>"Patrick Farrell <pfarrell@whamcloud.com>" uploaded a new patch: <a href="https://review.whamcloud.com/46714" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/46714</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-15619" title="Reduce size of cl_page and associated structures" class="issue-link" data-issue-key="LU-15619"><del>LU-15619</del></a> osc: Remove oap_cli<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: 1a257e6e328efe03e3cb323ba43910653baa4a93</p> <p>"Patrick Farrell <pfarrell@whamcloud.com>" uploaded a new patch: <a href="https://review.whamcloud.com/46715" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/46715</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-15619" title="Reduce size of cl_page and associated structures" class="issue-link" data-issue-key="LU-15619"><del>LU-15619</del></a> osc: Rename brw_page members<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: 1b4fef9bd1827e85229a38cce03c8c3dcc671eeb</p> <p>"Patrick Farrell <pfarrell@whamcloud.com>" uploaded a new patch: <a href="https://review.whamcloud.com/46716" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/46716</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-15619" title="Reduce size of cl_page and associated structures" class="issue-link" data-issue-key="LU-15619"><del>LU-15619</del></a> osc: Remove oap_obj pointer<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: b0e91948b8add615607f938bfe2ffcc236fe6c8f</p> <p>"Patrick Farrell <pfarrell@whamcloud.com>" uploaded a new patch: <a href="https://review.whamcloud.com/46717" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/46717</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-15619" title="Reduce size of cl_page and associated structures" class="issue-link" data-issue-key="LU-15619"><del>LU-15619</del></a> clio: Remove vpg_page pointer<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: e3d4b9e79deb4f20bd941da9c11c94c1dbf3b89a</p> <p>"Patrick Farrell <pfarrell@whamcloud.com>" uploaded a new patch: <a href="https://review.whamcloud.com/46718" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/46718</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-15619" title="Reduce size of cl_page and associated structures" class="issue-link" data-issue-key="LU-15619"><del>LU-15619</del></a> lov: Remove lov_page slice<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: 2b879f4b930259bb2145b22c26155eb359c2aab8</p> <p>"Patrick Farrell <pfarrell@whamcloud.com>" uploaded a new patch: <a href="https://review.whamcloud.com/46719" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/46719</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-15619" title="Reduce size of cl_page and associated structures" class="issue-link" data-issue-key="LU-15619"><del>LU-15619</del></a> osc: Remove oap lock<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: f6ed526c415de316b7399bc8a5a8d7aebb9adfdb</p> <p>"Patrick Farrell <pfarrell@whamcloud.com>" uploaded a new patch: <a href="https://review.whamcloud.com/46721" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/46721</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-15619" title="Reduce size of cl_page and associated structures" class="issue-link" data-issue-key="LU-15619"><del>LU-15619</del></a> osc: Pack osc_async_page better<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: 566fd06ae372ed1143f6626f1f71e5d44589ceb0</p> <p>I was looking at whether <tt>osc_oap_page.oap_cmd</tt> could be made smaller, but I see it is already 18 bits <img class="emoticon" src="https://jira.whamcloud.com/images/icons/emoticons/warning.png" height="16" width="16" align="absmiddle" alt="" border="0"/> in size:</p> <div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent"> <pre class="code-java"> #define OBD_BRW_OVER_PRJQUOTA 0x8000 <span class="code-comment">/* Running out of project quota */</span> #define OBD_BRW_RDMA_ONLY 0x20000 <span class="code-comment">/* RPC contains RDMA-only pages*/</span> #define OBD_BRW_SYS_RESOURCE 0x40000 <span class="code-comment">/* page has CAP_SYS_RESOURCE */</span> </pre> </div></div> <p>Both <tt>osc_queue_async_io()</tt> and <tt>osc_page_submit()</tt> explicitly (try to) store <tt>OBD_BRW_SYS_RESOURCE</tt> in <tt>oap_cmd</tt> (also in <tt>oap_brw_flags</tt> aka <tt>oap_brw_page.flag</tt>), but not much else goes in there (<tt>OBD_BRW_WRITE</tt>, <tt>OBD_BRW_NOQUOTA</tt>).</p> <p>It doesn't <b>look</b> like <tt>oap_cmd</tt> is used for anything other than checking <tt>OBD_BRW_WRITE</tt>, so this could become a single bitfield, or added to <tt>oap_async_flags</tt>?</p> <p>Note that modern GCC allows you to use:</p> <div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent"> <pre class="code-java"> <span class="code-keyword">enum</span> async_flags oap_async_flags:4; </pre> </div></div> <p>to reduce the size, while keeping the consistency checks, though I don't think it makes a difference right now. </p> <p>Shrinking <tt>oap_page_off</tt> to <tt>PAGE_SIZE_BITS</tt> won't help by itself either, but gets this down to 12 bits (16 on PPC64/ARM64, since the offset is zero-based it never needs the full range). It probably wants to live on a 2-byte boundary so that it doesn't need to be shifted for each use, unlike the flags.</p> <p>I also noticed that <tt>brw_page</tt> has a <tt>__u32</tt> padding at the end, which (by itself) doesn't help, but together with the above changes that would save another 8 bytes from <tt>osc_oap_page</tt>?</p> <p>"Oleg Drokin <green@whamcloud.com>" merged in patch <a href="https://review.whamcloud.com/c/fs/lustre-release/+/46713/" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/c/fs/lustre-release/+/46713/</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-15619" title="Reduce size of cl_page and associated structures" class="issue-link" data-issue-key="LU-15619"><del>LU-15619</del></a> osc: Remove oap_magic<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: <br/> Commit: 721df28648c4b3faabce709abce7d55512edbeac</p> <p>"Oleg Drokin <green@whamcloud.com>" merged in patch <a href="https://review.whamcloud.com/c/fs/lustre-release/+/46719/" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/c/fs/lustre-release/+/46719/</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-15619" title="Reduce size of cl_page and associated structures" class="issue-link" data-issue-key="LU-15619"><del>LU-15619</del></a> osc: Remove oap lock<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: <br/> Commit: b2274a716087fad24490f56026775886c26f74b8</p> <p>"Oleg Drokin <green@whamcloud.com>" merged in patch <a href="https://review.whamcloud.com/c/fs/lustre-release/+/46721/" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/c/fs/lustre-release/+/46721/</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-15619" title="Reduce size of cl_page and associated structures" class="issue-link" data-issue-key="LU-15619"><del>LU-15619</del></a> osc: pack osc_async_page better<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: <br/> Commit: 0bfc8eca5c3d26235846bab347d7e53b8ab0576a</p> <p>"Oleg Drokin <green@whamcloud.com>" merged in patch <a href="https://review.whamcloud.com/c/fs/lustre-release/+/46715/" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/c/fs/lustre-release/+/46715/</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-15619" title="Reduce size of cl_page and associated structures" class="issue-link" data-issue-key="LU-15619"><del>LU-15619</del></a> osc: Rename brw_page members<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: <br/> Commit: f2d875daf385ae6bb98045d16d9552a486a89263</p> <p>Landed for 2.16</p> Related LU-10994 Development Rank 1|i02k0v: Rank (Obsolete) 9223372036854775807