well as avoiding a switch statement. This change has no significant impact
to performance when branch prediction is successful at predicting the sizes
of objects passed to free(), but in the case that the object sizes are
semi-random, this change has the potential to prevent many branch prediction
misses, thus improving performance substantially.
Take advantage of alignment guarantees in ipalloc(), and pad object sizes to
something less than a power of two when possible. This has the potential
to substantially reduce internal fragmentation for objects allocated via
posix_memalign().
Avoid an unnecessary pow2_ceil() call in arena_ralloc().
Submitted by: djam8193ah@hotmail.com
and instead creating a small allocation for each malloc(0) call. The
optional SysV compatibility behavior remains unchanged.
Add a couple of assertions.
Fix a couple of typos in error message strings.
The text is correct in the "DESCRIPTION" section, so fix "SYNOPSIS"
to use the correct name.
PR: docs/90498
Submitted by: Vasil Dimov
MFC after: 3 days
If the initial buffer size (1KB) for the given group line is not big
enough, reset the offset. It helps to do not miss this line when
getrg() reallocates the larger buffer and tries to parse the line again.
PR: bin/52433, kern/55031, bin/83696, misc/97640, misc/98111
Submitted by: bsw71@mail.ru, Philip M. Gollucci, Justin Erenkrantz
Glanced at: nectar
MFC after: 1 month
objects with SF_IMMUTABLE, SF_APPEND, or SF_NOUNLINK.
* Document that non-superusers cannot set or clear any SF_* flag
(setting fails with EPERM, clearing is silently ignored).
* Document that superusers cannot change any flag if one of
SF_IMMUTABLE, SF_APPEND, SF_NOUNLINK is set and securelevel is
greater than 0.
* Document SF_SNAPSHOT and note that it is maintained by the
system and is, for this reason, impossible to set to clear by
any user.
PR: docs/33877
Submitted by: harti
Help by: George Marsellis <gam9478@njit.edu>
MFC after: 1 week
4kB pages), in order to avoid dangerous rounding error when calculating
fullness limits during run promotion/demotion.
Convert a structure bitfield to a normal field in areana_run_t. This should
have been changed along with the other fields in revision 1.120.
bounds. [1]
Modify logic for utilizing the data segment, such that it is possible to
create huge allocations there.
Shrink the data segment when deallocating a chunk, if it is at the end of
the data segment.
Rename chunk_size to csize in huge_malloc(), in order to avoid masking a
static variable of the same name. [1]
Reported by: Paul Allen <nospam@ugcs.caltech.edu>
as well as add __sparc_utrap_install to FBSD_1.0; these are required by
the SCD libc 64 psABI and thus meant to be officially exported symbols.
- Remove the __fpu_* entries as well as the __sigtramp entry altogether as
these are internal to the libc FPU emulation and the signal trampoline
initialization in sigaction(2) respectively and thus don't need to be
externally visible.
- Add __sparc_utrap_setup to the list of FBSDprivate symbols as it's used
in src/lib/csu/sparc64/crt1.c to initialize the libc FPU emulation (I
think alternatively src/lib/csu/sparc64/crt1.c could be changed to use
__sparc_utrap_install instead, at the expense of increasing the size of
executables a bit).
- Add an entry for the vfork symbol to the FBSD_1 list and entries for it's
associated symbols generated by the RSYSCALL() macro to the FBSDprivate
list. There's some magic in place that automatically generates code for
vfork() if there's no explicit MD code for it so it might make sense to
move these symbols from the MD symbol map files to a MI one.
The last two changes make the libc symbol versioning useable on sparc64.
Ok'ed by: deischen
races. This isn't currently necessary for libpthread or libthr, but
without it external threads libraries like the linuxthreads port are
not safe to use.
Reported by: ganbold@micom.mng.net
have to be calculated once per allocator operation.
Make nil const.
Update various comments.
Remove/avoid division where possible.
For the one division operation that remains in the critical path, add a
switch statement that has a case for each small size class, and do division
with a constant divisor in each case. This allows the compiler to generate
optimized code that does not use hardware division [1].
Obtained from: peter [1]
this is used by some 3rd party applications when {e,f,g}cvt() are
not found. POSIX defines the xcvt() funtions but says they are
deprecated in favor or sprintf(). We'll import these functions
from OpenBSD and remove __gdtoa() from the exported interfaces
when libc version is bumped.
* Avoid choosing an arena until it's certain that an arena is needed
for allocation.
* Convert division/multiplication to bitshifting where possible.
* Avoid accessing TLS variables in single-threaded code.
* Reduce the amount of pointer dereferencing.
* Move lock acquisition in critical paths to only protect the the code
that requires synchronization, and completely remove locking where
possible.
uses them.
Now, we have res_nupdate and res_nmkupdate as well, but they are
still based on our old resolver for binary backward compatibility.
So, they don't provide new features such as TSIG support.
Reported by: pointyhat via kris
FBSDprivate locale symbols. These functions are needed by
libcompat.
Add _cleanup to the list of stdio FBSDprivate symbols. Some
third party applications use this. This will be removed and
replaced by fcloseall() once libc version is bumped.
Add _res to the list of resolv symbols.
Found by: portbuilder runs (thanks Kris!)
determine its value at run time according to other relevant values. This
avoids the creation of runs that are incompletely utilized, as long as
pagesize isn't too large (>32kB, given the current RUN_MIN_REGS_2POW
setting).
Increase the size of several structure bitfields in arena_run_t in order
to avoid integer overflow in the case that a run's header does not overlap
with the space that is usable as application allocation regions. Given
the tiny_min_2pow change, this fix has no additional impact unless
pagesize is >32kB.
Reported by: kris
internally used chunk to start at the beginning of the heap, rather
than at a chunk-aligned address. This reduces mapped memory somewhat
for 32-bit architectures.
Add the arena_run_link_t type and use it wherever a run object is only
used as a ring 'header'. This saves approximately 40 kB of memory per
arena.
Remove an obsolete (no longer used) code path from base_alloc(), which
supported the internal allocation of objects larger than the chunk
size.
Enhance chunk_dealloc() to cache chunk addresses for all deallocated
chunks. This has no impact for most programs, but has the potential
to reduce VM map fragmentation for programs that use huge
allocations.
documentation bug. We switched to page indexes some time around
FreeBSD 2.2. The actual 'len' limit is the maximum file size or what
will fit in your address space, whichever comes first. It should be
possible to make 1TB files on 32 bit systems, but of course address space
runs out long before then.
Since, res_sendsigned(3) and the friends use MD5 functions, it is
hard to include them without having MD5 functions in libc. So,
res_sendsigned(3) is not merged into libc.
Since, res_update(3) in BIND9 is not binary compatible with our
res_update(3), res_update(3) is leaved as is, except some
necessary modifications.
The res_update(3) and the friends are not essential part of the
resolver. They are not defined in resolv.h but defined in
res_update.h separately in BIND9. Further, they are not called from
our tree. So, I hide them from our resolv.h, but leave them only
for binary backward compatibility (perhaps, no one calls them).
Since, struct __res_state_ext is not exposed in BIND9, I hide it
from our resolv.h. And, global variable _res_ext is removed. It
breaks binary backward compatibility. But, since it is not used from
outside of our libc, I think it is safe.
Reviewed by: arch@ (no objection)
that no linear searching is necessary if we resort to allocating from a
run that is known to be mostly full. There are pathological edge cases
that could have caused severely degraded performance, and this change
fixes that.
close enough to each other that reallocation would allocate a new region
of the same size. This improves the performance of repeated incremental
reallocations by up to three orders of magnitude. [1]
Fix arena_new() to properly constrain run size if a small chunk size was
specified during runtime configuration.
Suggested by: se [1]
allocation patterns that involve a relatively even mixture of many
different size classes.
Reduce the chunk size from 16 MB to 2 MB. Since chunks are now carved up
using an address-ordered first best fit policy, VM map fragmentation is
much less likely, which makes smaller chunks not as much of a risk. This
reduces the virtual memory size of most applications.
Remove redzones, since program buffer overruns are no longer as likely to
corrupt malloc data structures.
Remove the C MALLOC_OPTIONS flag, and add H and S.
