Increase maximum read-only mmap()s used from 1000 to 4096 on 64-bit systems #1265
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…ystems By default LevelDB will only mmap() up to 1000 ldb files for reading and then fall back to using file desciptors. The typical linux system has a 'vm.max_map_count = 65530', so mapping only 1000 files seems arbitarily small. Increase this value to another arbitrarily small value, 4096. Original change by Clem Taylor. Ported to LevelDB 1.22 by Wladimir J. van der Laan.
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i'm confused, maybe there is value in changing the default, but why do we patch leveldb here when it could be set from client code: |
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Are you suggesting we revert it in Bitcoin instead? |
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Ideally yes, looking into it. Sure, upstream leveldb might still want to change this default but i find it hard to argue "why 4096". Hah i like the commit message: |
laanwj
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May 8, 2025
Set the default leveldb mmap limit to 4096 from dbwrapper, before creating the first leveldb context. The motivation here is to remove the need for a leveldb patch, see google/leveldb#1265.
laanwj
added a commit
to laanwj/bitcoin
that referenced
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May 8, 2025
Set the default leveldb mmap limit to 4096 from dbwrapper, before creating the first leveldb context. The motivation here is to remove the need for a leveldb patch, see google/leveldb#1265.
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Okay this turned out so much worse than i hoped, on the upside, maybe we can just drop this patch: bitcoin/bitcoin#32447 |
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Cherry-picking bitcoin-core@92ae82c and revives #613