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authorSergey Poznyakoff <gray@gnu.org.ua>2011-08-10 22:00:34 (GMT)
committer Sergey Poznyakoff <gray@gnu.org.ua>2011-08-10 22:00:34 (GMT)
commit74f7fe561e31637bdbf21aeb817d4a22bbf9c91a (patch) (side-by-side diff)
treebae9da9f2c749d290ad4f1764dc205bcd23b750e /doc/gdbm.texinfo
parent6b6dcc80555d77858733e44b72e92d1dc60e2c38 (diff)
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Improve memory mapping support.
The new code is more flexible and performs better when lots of inserts are being made (e.g. when populating the database with new data). * src/gdbm.h.in (GDBM_SETMAXMAPSIZE): New constant. * src/gdbmconst.h (SIZE_T_MAX): New define. * src/gdbmdefs.h (gdbm_file_info) <cache_size>: Change type to size_t. <mmap_inited,mapped_size_max>: New member. <mapped_remap>: Remove. * src/gdbmopen.c: Fix a typo. (gdbm_open): Initialize new members. (_gdbm_init_cache): Second argument is size_t. * src/gdbmsetopt.c (gdbm_setopt): Optval argument is void*. Handle GDBM_SETMAXMAPSIZE. Improve error checking. * src/mmap.c (_GDBM_IN_MAPPED_REGION_P): Fix comparison with the lower bound. (_GDBM_NEED_REMAP): Return true if mapped_region is NULL. (SUM_FILE_SIZE): Rewrite. (_gdbm_mapped_unmap): Don't call msync. (_gdbm_internal_remap): Take 2 arguments, the second one giving the new mapped size. Unmap the region prior to remapping it. Always pass NULL as the argument to mmap. (_gdbm_mapped_remap): Rewrite the logic. Change semantics of the third argument. All uses updated. (_gdbm_mapped_init): Reflect the above changes. (_gdbm_mapped_read,_gdbm_mapped_write): Use mmap_inited to decide whether to use mmap, because mapped_region can be reset to zero by another functions (namely, _gdbm_mapped_lseek). Reset mmap_inited to FALSE, if _gdbm_mapped_remap fails. (_gdbm_mapped_lseek): Rewrite offset computations. Invalidate the mapped region. * src/proto.h (_gdbm_init_cache): Change prototype. * src/update.c (write_header, _gdbm_end_update): Remove checks for dbf->mapped_region. * tests/gtload.c: Implement the -maxmap option (set maximal mapped memory size). * doc/gdbm.texinfo: Document GDBM_SETMAXMAPSIZE.
Diffstat (limited to 'doc/gdbm.texinfo') (more/less context) (ignore whitespace changes)
-rw-r--r--doc/gdbm.texinfo10
1 files changed, 9 insertions, 1 deletions
diff --git a/doc/gdbm.texinfo b/doc/gdbm.texinfo
index c349941..5dc8a97 100644
--- a/doc/gdbm.texinfo
+++ b/doc/gdbm.texinfo
@@ -738,7 +738,7 @@ The @var{errno} argument is usually the value of the global variable
open database.
@deftypefn {gdbm interface} int gdbm_setopt (GDBM_FILE @var{dbf}, int @var{option}, @
- int *@var{value}, int @var{size})
+ void *@var{value}, int @var{size})
Sets an option on the database.
The parameters are:
@@ -809,6 +809,14 @@ a @acronym{CPU} expensive process with time, though, especially if
used in conjunction with GDBM_CENTFREE. The @var{value} should point
to an integer: @samp{TRUE} to turn free block merging on, and @samp{FALSE} to
turn it off.
+
+@kwindex GDBM_SETMAXMAPSIZE
+@item GDBM_SETMAXMAPSIZE
+Sets maximum size of the memory mapped region. The @var{value} should
+point to a value of type @code{size_t}, @code{unsigned long} or
+@code{unsigned}. The actual value is rounded to the nearest page
+boundary (the page size is obtained from
+@code{sysconf(_SC_PAGESIZE)}).
@end table
The return value will be @samp{-1} upon failure, or @samp{0} upon

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