46a6b5c451
mountd.c uses a single linked list of "struct exportlist" structures, where there is one of these for each exported file system on the NFS server. This list gets long if there are a large number of file systems exported and the list must be searched for each line in the exports file(s) when SIGHUP causes the exports file(s) to be reloaded. A simple benchmark that traverses SLIST() elements and compares two 32bit fields in the structure for equal (which is what the search is) appears to take a couple of nsec. So, for a server with 72000 exported file systems, this can take about 5sec during reload of the exports file(s). By replacing the single linked list with a hash table with a target of 10 elements per list, the time should be reduced to less than 1msec. Peter Errikson (who has a server with 72000+ exported file systems) ran a test program using 5 hashes to see how they worked. fnv_32_buf(fsid,..., 0) fnv_32_buf(fsid,..., FNV1_32_INIT) hash32_buf(fsid,..., 0) hash32_buf(fsid,..., HASHINIT) - plus simply using the low order bits of fsid.val[0]. The first three behaved about equally well, with the first one being slightly better than the others. It has an average variation of about 4.5% about the target list length and that is what this patch uses. Peter Errikson also tested this hash table version and found that the performance wasn't measurably improved by a larger hash table, so a load factor of 10 appears adequate. Tested by: pen@lysator.liu.se (with other patches) PR: 237860 MFC after: 1 month |
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| bin | ||
| cddl | ||
| contrib | ||
| crypto | ||
| etc | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| stand | ||
| sys | ||
| targets | ||
| tests | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| .arcconfig | ||
| .arclint | ||
| .cirrus.yml | ||
| .gitattributes | ||
| .gitignore | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| Makefile.libcompat | ||
| Makefile.sys.inc | ||
| ObsoleteFiles.inc | ||
| README | ||
| README.md | ||
| UPDATING | ||
FreeBSD Source:
This is the top level of the FreeBSD source directory. This file
was last revised on:
FreeBSD
FreeBSD is an operating system used to power modern servers, desktops, and embedded platforms. A large community has continually developed it for more than thirty years. Its advanced networking, security, and storage features have made FreeBSD the platform of choice for many of the busiest web sites and most pervasive embedded networking and storage devices.
For copyright information, please see the file COPYRIGHT in this directory. Additional copyright information also exists for some sources in this tree - please see the specific source directories for more information.
The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree. See build(7), config(8), https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html, and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html for more information, including setting make(1) variables.
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include System include files.
kerberos5 Kerberos5 (Heimdal) package.
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