freebsd kernel with SKQ
bd4bd019fb
is to first write the deleted directory entry to disk, second write the zero'ed inode to disk, and finally to release the freed blocks and the inode back to the cylinder-group map. As this ordering requires two disk writes to occur which are normally spaced about 30 seconds apart (except when memory is under duress), it takes about a minute from the time that a file is deleted until its inode and data blocks show up in the cylinder-group map for reallocation. If a file has had only a brief lifetime (less than 30 seconds from creation to deletion), neither its inode nor its directory entry may have been written to disk. If its directory entry has not been written to disk, then we need not wait for that directory block to be written as the on-disk directory block does not reference the inode. Similarly, if the allocated inode has never been written to disk, we do not have to wait for it to be written back either as its on-disk representation is still zero'ed out. Thus, in the case of a short lived file, we can simply release the blocks and inode to the cylinder-group map immediately. As the inode and its blocks are released immediately, they are immediately available for other uses. If they are not released for a minute, then other inodes and blocks must be allocated for short lived files, cluttering up the vnode and buffer caches. The previous code was a bit too aggressive in trying to release the blocks and inode back to the cylinder-group map resulting in their being made available when in fact the inode on disk had not yet been zero'ed. This patch takes a more conservative approach to doing the release which avoids doing the release prematurely. |
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| bin | ||
| contrib | ||
| crypto | ||
| etc | ||
| games | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| kerberosIV | ||
| lib | ||
| libexec | ||
| release | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| COPYRIGHT | ||
| Makefile | ||
| Makefile.inc1 | ||
| Makefile.upgrade | ||
| README | ||
| UPDATING | ||
This is the top level of the FreeBSD source directory. This file was last revised on: $FreeBSD$ 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, the most commonly used one being ``world'', which rebuilds and installs everything in the FreeBSD system from the source tree except the kernel, the kernel-modules and the contents of /etc. The ``buildkernel'' and ``installkernel'' targets build and install the kernel and the modules (see below). Please see the top of the Makefile in this directory for more information on the standard build targets and compile-time flags. Building a kernel is a somewhat more involved process, documentation for which can be found at: http://www.freebsd.org/handbook/kernelconfig.html And in the config(8) man page. Note: If you want to build and install the kernel with the ``buildkernel'' and ``installkernel'' targets, you have to build world before. More information is available in the handbook. The sample kernel configuration files reside in the sys/i386/conf sub-directory (assuming that you've installed the kernel sources), the file named GENERIC being the one used to build your initial installation kernel. The file NOTES contains entries and documentation for all possible devices, not just those commonly used. It is the successor of the ancient LINT file, but in contrast to LINT, it is not buildable as a kernel but a pure reference and documentation file. Source Roadmap: --------------- bin System/User commands. contrib Packages contributed by 3rd parties. crypto Cryptography stuff (see crypto/README). etc Template files for /etc games Amusements. gnu Various commands and libraries under the GNU Public License. Please see gnu/COPYING* for more information. include System include files. kerberosIV Kerberos package. lib System libraries. libexec System daemons. release Release building Makefile & associated tools. sbin System commands. secure Cryptographic libraries and commands. share Shared resources. sys Kernel sources. tools Utilities for regression testing and miscellaneous tasks. usr.bin User commands. usr.sbin System administration commands. For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see: http://www.freebsd.org/handbook/synching.html