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Two malloc arenas 19527875ebdc

glibc gives each thread that allocates an arena of its own and keeps
what is freed there. The first commit of the Linux tree, read and
hashed across four threads, peaked at 4.3 GB resident for 2.7 GB in
use; with two arenas it peaks at 3.1 GB, no slower. MALLOC_ARENA_MAX,
when set, still decides.

refs #35
Author
Andy McCall @andymccall <[email protected]>
When
· 2026-09-30 08:10 UTC
Signature
✔ signed by Andy McCall
Hash
19527875ebdc04f181f5283fed0256f3b7d588531f9c096489eae397aff944cc
Depends on
5b1114a04905 d443639bcf35 ff0af1ee299d
Depended on by
e0d56dfca51d
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modified src/main.rs +10 −0
… 
15 unchanged lines
16 16 
    unsafe {
17 17 
        libc::signal(libc::SIGPIPE, libc::SIG_DFL);
18 18 
    }
19 + 
    // glibc gives each thread that allocates an arena of its own and keeps
20 + 
    // what is freed there: the first commit of the Linux tree, read and
21 + 
    // hashed across threads, held 4.3 GB for 2.7 GB in use. Two arenas
22 + 
    // hold 3.1 GB, no slower. MALLOC_ARENA_MAX still has the last word.
23 + 
    #[cfg(all(target_os = "linux", target_env = "gnu"))]
24 + 
    if std::env::var_os("MALLOC_ARENA_MAX").is_none() {
25 + 
        unsafe {
26 + 
            libc::mallopt(libc::M_ARENA_MAX, 2);
27 + 
        }
28 + 
    }
19 29 
    let result = cli::run();
20 30 
    oxy_core::timing::memory_summary();
21 31 
    match result {
… 
8 unchanged lines