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![]() jemalloc performs two types of virtual memory allocations: (1) large chunks of virtual memory, where the chunk size is a multiple of a superpage and explicitly aligned, and (2) small allocations, mostly 128KB, where no alignment is requested. Typically, it starts with a small allocation, and over time it makes both types of allocation. With anon_loc being updated on every allocation, we wind up with a repeating pattern of a small allocation, a large gap, and a large, aligned allocation. (As an aside, we wind up allocating a reservation for these small allocations, but it will never fill because the next large, aligned allocation updates anon_loc, leaving a gap that will never be filled with other small allocations.) With this change, anon_loc isn't updated on every allocation. So, the small allocations will be clustered together, the large allocations will be clustered together, and there will be fewer gaps between the anonymous memory allocations. In addition, I see a small reduction in reservations allocated (e.g., 1.6% during buildworld), fewer partially populated reservations, and a small increase in 64KB page promotions on arm64. Reviewed by: kib MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D39845 |
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amd64 | ||
arm | ||
arm64 | ||
bsm | ||
cam | ||
cddl | ||
compat | ||
conf | ||
contrib | ||
crypto | ||
ddb | ||
dev | ||
dts | ||
fs | ||
gdb | ||
geom | ||
gnu | ||
i386 | ||
isa | ||
kern | ||
kgssapi | ||
libkern | ||
modules | ||
net | ||
net80211 | ||
netgraph | ||
netinet | ||
netinet6 | ||
netipsec | ||
netlink | ||
netpfil | ||
netsmb | ||
nfs | ||
nfsclient | ||
nfsserver | ||
nlm | ||
ofed | ||
opencrypto | ||
powerpc | ||
riscv | ||
rpc | ||
security | ||
sys | ||
teken | ||
tests | ||
tools | ||
ufs | ||
vm | ||
x86 | ||
xdr | ||
xen | ||
Makefile | ||
README.md |
FreeBSD Kernel Source:
This directory contains the source files and build glue that make up the FreeBSD kernel and its modules, including both original and contributed software.
Kernel configuration files are located in the conf/
subdirectory of each
architecture. GENERIC
is the configuration used in release builds. NOTES
contains documentation of all possible entries. LINT
is a compile-only
configuration used to maximize build coverage and detect regressions.
Documentation:
Source code documentation is maintained in a set of man pages, under section 9.
These pages are located in share/man/man9
, from the
top-level of the src tree. Consult intro(9)
for an overview of existing pages.
Some additional high-level documentation of the kernel is maintained in the Architecture Handbook.
Source Roadmap:
Directory | Description |
---|---|
amd64 | AMD64 (64-bit x86) architecture support |
arm | 32-bit ARM architecture support |
arm64 | 64-bit ARM (AArch64) architecture support |
cam | Common Access Method storage subsystem - cam(4) and ctl(4) |
cddl | CDDL-licensed optional sources such as DTrace |
conf | kernel build glue |
compat | Linux compatibility layer, FreeBSD 32-bit compatibility |
contrib | 3rd-party imported software such as OpenZFS |
crypto | crypto drivers |
ddb | interactive kernel debugger - ddb(4) |
fs | most filesystems, excluding UFS, NFS, and ZFS |
dev | device drivers and other arch independent code |
gdb | kernel remote GDB stub - gdb(4) |
geom | GEOM framework - geom(4) |
i386 | i386 (32-bit x86) architecture support |
kern | main part of the kernel |
libkern | libc-like and other support functions for kernel use |
modules | kernel module infrastructure |
net | core networking code |
net80211 | wireless networking (IEEE 802.11) - net80211(4) |
netgraph | graph-based networking subsystem - netgraph(4) |
netinet | IPv4 protocol implementation - inet(4) |
netinet6 | IPv6 protocol implementation - inet6(4) |
netipsec | IPsec protocol implementation - ipsec(4) |
netpfil | packet filters - ipfw(4) , pf(4) , and ipfilter(4) |
opencrypto | OpenCrypto framework - crypto(7) |
powerpc | PowerPC/POWER (32 and 64-bit) architecture support |
riscv | 64-bit RISC-V architecture support |
security | security facilities - audit(4) and mac(4) |
sys | kernel headers |
tests | kernel unit tests |
ufs | Unix File System - ffs(7) |
vm | virtual memory system |
x86 | code shared by AMD64 and i386 architectures |