<div>Hi, I am using swap_notify now. However I have noticed that although the ComprDataSize shrinks as swap is freed, the MemUsedTotal stays relatively high. Presumably this is caused by the swap being freed from effectively random locations in memory, meaning that most of the allocated pages cannot be freed.</div>
<div><br></div><div>Does this suggest that defragmenting the memory allocated by comp-cache may be worthwhile in some circumstances? </div><div><br></div><div>After doing an interrupted swap off the ratio became even worse. Although compcache managed to free some memory, memory fragmentation rose to 66%.</div>
<div><br></div><div>FYI, here are all the relevant stats below. Previously 1GB of swap was used. Also note that 750MB of memory is currently free, so in this case there is no short term benefit to be gained from defragmenting the memory allocated by compcache.</div>
<div><br></div><div>----</div><div><br></div><div>After closing some windows, my swap usage dropped from 1GB to 411MB, but MemUsedTotal remained high.</div><div><br></div><div>xp@xp-desktop:/mnt/big/xp/images/share/Ubuntu904/keytest$ rzstats</div>
<div>BackingSwap:<span class="Apple-tab-span" style="white-space:pre"> </span>/old/swap_4.dd</div><div>DiskSize:<span class="Apple-tab-span" style="white-space:pre"> </span> 4194304 kB</div><div>MemLimit:<span class="Apple-tab-span" style="white-space:pre"> </span> 1000000 kB</div>
<div>NumReads:<span class="Apple-tab-span" style="white-space:pre"> </span> 1408562</div><div>NumWrites:<span class="Apple-tab-span" style="white-space:pre"> </span> 1047863</div><div>FailedReads:<span class="Apple-tab-span" style="white-space:pre"> </span> 0</div>
<div>FailedWrites:<span class="Apple-tab-span" style="white-space:pre"> </span> 0</div><div>InvalidIO:<span class="Apple-tab-span" style="white-space:pre"> </span> 0</div><div>NotifyFree:<span class="Apple-tab-span" style="white-space:pre"> </span> 814586</div>
<div>PagesDiscard:<span class="Apple-tab-span" style="white-space:pre"> </span> 0</div><div>ZeroPages:<span class="Apple-tab-span" style="white-space:pre"> </span> 14374</div><div>GoodCompress:<span class="Apple-tab-span" style="white-space:pre"> </span> 100 %</div>
<div>NoCompress:<span class="Apple-tab-span" style="white-space:pre"> </span> 0 %</div><div>PagesStored:<span class="Apple-tab-span" style="white-space:pre"> </span> 102777</div><div>PagesUsed:<span class="Apple-tab-span" style="white-space:pre"> </span> 41309</div>
<div>OrigDataSize:<span class="Apple-tab-span" style="white-space:pre"> </span> 411108 kB</div><div>ComprDataSize:<span class="Apple-tab-span" style="white-space:pre"> </span> 91324 kB</div><div>MemUsedTotal:<span class="Apple-tab-span" style="white-space:pre"> </span> 165236 kB</div>
<div>BDevNumReads:<span class="Apple-tab-span" style="white-space:pre"> </span> 171419</div><div>BDevNumWrites:<span class="Apple-tab-span" style="white-space:pre"> </span> 113780</div><div>xp@xp-desktop:/mnt/big/xp/images/share/Ubuntu904/keytest$ cat /proc/meminfo </div>
<div>MemTotal: 3926280 kB</div><div>MemFree: 746780 kB</div><div>Buffers: 59964 kB</div><div>Cached: 839612 kB</div><div>SwapCached: 67460 kB</div><div>Active: 961052 kB</div>
<div>Inactive: 724740 kB</div><div>Active(anon): 564264 kB</div><div>Inactive(anon): 226532 kB</div><div>Active(file): 396788 kB</div><div>Inactive(file): 498208 kB</div><div>Unevictable: 16 kB</div>
<div>Mlocked: 16 kB</div><div>SwapTotal: 6756624 kB</div><div>SwapFree: 6294740 kB</div><div>Dirty: 184 kB</div><div>Writeback: 0 kB</div><div>AnonPages: 764088 kB</div>
<div>Mapped: 632852 kB</div><div>Slab: 121576 kB</div><div>SReclaimable: 90672 kB</div><div>SUnreclaim: 30904 kB</div><div>PageTables: 34272 kB</div><div>NFS_Unstable: 0 kB</div>
<div>Bounce: 0 kB</div><div>WritebackTmp: 0 kB</div><div>CommitLimit: 8719764 kB</div><div>Committed_AS: 2589344 kB</div><div>VmallocTotal: 34359738367 kB</div><div>VmallocUsed: 80404 kB</div>
<div>VmallocChunk: 34359654343 kB</div><div>HugePages_Total: 0</div><div>HugePages_Free: 0</div><div>HugePages_Rsvd: 0</div><div>HugePages_Surp: 0</div><div>Hugepagesize: 2048 kB</div><div>
DirectMap4k: 3806144 kB</div><div>DirectMap2M: 387072 kB</div><div><br></div><div><br></div><div>--</div><div><br></div><div>After doing a swapoff, and interruping it, almost half the memory was freed, but memory fragmentation ratio rose to 66%</div>
<div><br></div><div><div>xp@xp-desktop:/mnt/big/xp/images/share/Ubuntu904/keytest$ rzstats</div><div>BackingSwap:<span class="Apple-tab-span" style="white-space:pre"> </span>/old/swap_4.dd</div><div>DiskSize:<span class="Apple-tab-span" style="white-space:pre"> </span> 4194304 kB</div>
<div>MemLimit:<span class="Apple-tab-span" style="white-space:pre"> </span> 1000000 kB</div><div>NumReads:<span class="Apple-tab-span" style="white-space:pre"> </span> 1466336</div><div>NumWrites:<span class="Apple-tab-span" style="white-space:pre"> </span> 1047863</div>
<div>FailedReads:<span class="Apple-tab-span" style="white-space:pre"> </span> 0</div><div>FailedWrites:<span class="Apple-tab-span" style="white-space:pre"> </span> 0</div><div>InvalidIO:<span class="Apple-tab-span" style="white-space:pre"> </span> 0</div>
<div>NotifyFree:<span class="Apple-tab-span" style="white-space:pre"> </span> 875438</div><div>PagesDiscard:<span class="Apple-tab-span" style="white-space:pre"> </span> 0</div><div>ZeroPages:<span class="Apple-tab-span" style="white-space:pre"> </span> 14374</div>
<div>GoodCompress:<span class="Apple-tab-span" style="white-space:pre"> </span> 100 %</div><div>NoCompress:<span class="Apple-tab-span" style="white-space:pre"> </span> 0 %</div><div>PagesStored:<span class="Apple-tab-span" style="white-space:pre"> </span> 41925</div>
<div>PagesUsed:<span class="Apple-tab-span" style="white-space:pre"> </span> 22792</div><div>OrigDataSize:<span class="Apple-tab-span" style="white-space:pre"> </span> 167700 kB</div><div>ComprDataSize:<span class="Apple-tab-span" style="white-space:pre"> </span> 33310 kB</div>
<div>MemUsedTotal:<span class="Apple-tab-span" style="white-space:pre"> </span> 91168 kB</div><div>BDevNumReads:<span class="Apple-tab-span" style="white-space:pre"> </span> 175369</div><div>BDevNumWrites:<span class="Apple-tab-span" style="white-space:pre"> </span> 113780</div>
<div>xp@xp-desktop:/mnt/big/xp/images/share/Ubuntu904/keytest$ cat /proc/meminfo </div><div>MemTotal: 3926280 kB</div><div>MemFree: 443012 kB</div><div>Buffers: 62972 kB</div><div>Cached: 872620 kB</div>
<div>SwapCached: 48956 kB</div><div>Active: 1055912 kB</div><div>Inactive: 964876 kB</div><div>Active(anon): 652512 kB</div><div>Inactive(anon): 443684 kB</div><div>Active(file): 403400 kB</div>
<div>Inactive(file): 521192 kB</div><div>Unevictable: 16 kB</div><div>Mlocked: 16 kB</div><div>SwapTotal: 6756624 kB</div><div>SwapFree: 6560424 kB</div><div>Dirty: 100 kB</div>
<div>Writeback: 0 kB</div><div>AnonPages: 1071652 kB</div><div>Mapped: 733832 kB</div><div>Slab: 122624 kB</div><div>SReclaimable: 91676 kB</div><div>SUnreclaim: 30948 kB</div>
<div>PageTables: 35280 kB</div><div>NFS_Unstable: 0 kB</div><div>Bounce: 0 kB</div><div>WritebackTmp: 0 kB</div><div>CommitLimit: 8719764 kB</div><div>Committed_AS: 2684328 kB</div>
<div>VmallocTotal: 34359738367 kB</div><div>VmallocUsed: 80404 kB</div><div>VmallocChunk: 34359654343 kB</div><div>HugePages_Total: 0</div><div>HugePages_Free: 0</div><div>HugePages_Rsvd: 0</div>
<div>HugePages_Surp: 0</div><div>Hugepagesize: 2048 kB</div><div>DirectMap4k: 3806144 kB</div><div>DirectMap2M: 387072 kB</div><div><br></div></div><br>-- <br>John C. McCabe-Dansted<br>