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2014-10-30hashmap: rewrite the implementationMichal Schmidt
This is a rewrite of the hashmap implementation. Its advantage is lower memory usage. It uses open addressing (entries are stored in an array, as opposed to linked lists). Hash collisions are resolved with linear probing and Robin Hood displacement policy. See the references in hashmap.c. Some fun empirical findings about hashmap usage in systemd on my laptop: - 98 % of allocated hashmaps are Sets. - Sets contain 78 % of all entries, plain Hashmaps 17 %, and OrderedHashmaps 5 %. - 60 % of allocated hashmaps contain only 1 entry. - 90 % of allocated hashmaps contain 5 or fewer entries. - 75 % of all entries are in hashmaps that use trivial_hash_ops. Clearly it makes sense to: - store entries in distinct entry types. Especially for Sets - their entries are the most numerous and they require the least information to store an entry. - have a way to store small numbers of entries directly in the hashmap structs, and only allocate the usual entry arrays when the direct storage is full. The implementation has an optional debugging feature (enabled by defining the ENABLE_HASHMAP_DEBUG macro), where it: - tracks all allocated hashmaps in a linked list so that one can easily find them in gdb, - tracks which function/line allocated a given hashmap, and - checks for invalid mixing of hashmap iteration and modification. Since entries are not allocated one-by-one anymore, mempools are not used for entries. Originally I meant to drop mempools entirely, but it's still worth it to use them for the hashmap structs. My testing indicates that it makes loading of units about 5 % faster (a test with 10000 units where more than 200000 hashmaps are allocated - pure malloc: 449±4 ms, mempools: 427±7 ms). Here are some memory usage numbers, taken on my laptop with a more or less normal Fedora setup after booting with SELinux disabled (SELinux increases systemd's memory usage significantly): systemd (PID 1) Original New Change dirty memory (from pmap -x 1) [KiB] 2152 1264 -41 % total heap allocations (from gdb-heap) [KiB] 1623 756 -53 %
2014-10-23hashmap: allow hashmap_move() to failMichal Schmidt
It cannot fail in the current hashmap implementation, but it may fail in alternative implementations (unless a sufficiently large reservation has been placed beforehand).
2014-10-23hashmap: introduce hashmap_reserve()Michal Schmidt
With the current hashmap implementation that uses chaining, placing a reservation can serve two purposes: - To optimize putting of entries if the number of entries to put is known. The reservation allocates buckets, so later resizing can be avoided. - To avoid having very long bucket chains after using hashmap_move(_one). In an alternative hashmap implementation it will serve an additional purpose: - To guarantee a subsequent hashmap_move(_one) will not fail with -ENOMEM (this never happens in the current implementation).
2014-09-15hashmap, set: remove unused functionsMichal Schmidt
The following hashmap_* and set_* functions/macros have never had any users in systemd's history: *_iterate_backwards *_iterate_skip *_last *_FOREACH_BACKWARDS Remove this dead code.
2014-09-15hashmap: introduce hash_ops to make struct Hashmap smallerMichal Schmidt
It is redundant to store 'hash' and 'compare' function pointers in struct Hashmap separately. The functions always comprise a pair. Store a single pointer to struct hash_ops instead. systemd keeps hundreds of hashmaps, so this saves a little bit of memory.
2014-08-12networkd: expose a global list of DNS and NTP servers in the state fileLennart Poettering
2013-10-14util: allow trailing semicolons on define_trivial_cleanup_func linesLennart Poettering
Emacs C indenting really gets confused by these lines if they carry no trailing semicolon, hence let's make this nicer for good old emacs. The other macros which define functions already do this too, so let's copy the scheme here. Also, let's use an uppercase name for the macro. So far our rough rule was that macros that are totally not function-like (like this ones, which define a function) are uppercase. (Well, admittedly it is a rough rule only, for example function and variable decorators are all lower-case SINCE THE CONSTANT YELLING IN THE SOURCES WOULD SUCK, and also they at least got underscore prefixes.) Also, the macros that define functions that we already have are all uppercase, so let's do the same here...
2013-10-13Introduce udev object cleanup functionsZbigniew Jędrzejewski-Szmek
2013-04-24Add set_consume which always takes ownershipZbigniew Jędrzejewski-Szmek
Freeing in error path is the common pattern with set_put().
2013-04-16macro: rework how we define cleanup macrosLennart Poettering
There's now a generic _cleanup_ macro with an argument. The macros for specific types are now defined using this macro, and in the header files where they belong. All cleanup handlers are now inline functions.
2013-03-08shared: inline trivial auto-cleanup functionsMichal Schmidt
2013-01-29shared: introduce _cleanup_set_free_free_Zbigniew Jędrzejewski-Szmek
2013-01-07localectl: use automatic cleanupZbigniew Jędrzejewski-Szmek
set_freep() is added to automatize set_free().
2012-10-19set: introduce set_get_strv()Lennart Poettering
2012-08-14service: add options RestartPreventExitStatus and SuccessExitStatusLukas Nykryn
In some cases, like wrong configuration, restarting after error does not help, so administrator can specify statuses by RestartPreventExitStatus which will not cause restart of a service. Sometimes you have non-standart exit status, so this can be specified by SuccessfulExitStatus.
2012-07-19use #pragma once instead of foo*foo #define guardsShawn Landden
#pragma once has been "un-deprecated" in gcc since 3.3, and is widely supported in other compilers. I've been using and maintaining (rebasing) this patch for a while now, as it annoyed me to see #ifndef fooblahfoo, etc all over the place, almost arrogant about the annoyance of having to define all these names to perform a commen but neccicary functionality, when a completely superior alternative exists. I havn't sent it till now, cause its kindof a style change, and it is bad voodoo to mess with style that has been established by more established editors. So feel free to lambast me as a crazy bafoon. v2 - preserve externally used headers
2012-07-03load-fragment: a few modernizationsLennart Poettering
2012-04-12relicense to LGPLv2.1 (with exceptions)Lennart Poettering
We finally got the OK from all contributors with non-trivial commits to relicense systemd from GPL2+ to LGPL2.1+. Some udev bits continue to be GPL2+ for now, but we are looking into relicensing them too, to allow free copy/paste of all code within systemd. The bits that used to be MIT continue to be MIT. The big benefit of the relicensing is that closed source code may now link against libsystemd-login.so and friends.
2012-04-10util: move all to shared/ and split external dependencies in separate ↵Kay Sievers
internal libraries Before: $ ldd /lib/systemd/systemd-timestamp linux-vdso.so.1 => (0x00007fffb05ff000) libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f90aac57000) libcap.so.2 => /lib64/libcap.so.2 (0x00007f90aaa53000) librt.so.1 => /lib64/librt.so.1 (0x00007f90aa84a000) libc.so.6 => /lib64/libc.so.6 (0x00007f90aa494000) /lib64/ld-linux-x86-64.so.2 (0x00007f90aae90000) libdl.so.2 => /lib64/libdl.so.2 (0x00007f90aa290000) libattr.so.1 => /lib64/libattr.so.1 (0x00007f90aa08a000) libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f90a9e6e000) After: $ ldd systemd-timestamp linux-vdso.so.1 => (0x00007fff3cbff000) libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f5eaa1c3000) librt.so.1 => /lib64/librt.so.1 (0x00007f5ea9fbb000) libc.so.6 => /lib64/libc.so.6 (0x00007f5ea9c04000) /lib64/ld-linux-x86-64.so.2 (0x00007f5eaa3fc000) libdl.so.2 => /lib64/libdl.so.2 (0x00007f5ea9a00000) libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f5ea97e4000)