The core issue here is the weak linking of the symbol, and in certain
environments--for instance, using the latest Xcode (8.1) with the latest
SDK (10.12)--os_unfair_lock may resolve even though you're compiling on
a host that doesn't support it (10.11).
We can use the availability macros to circumvent this problem, and
detect that we're not compiling for a target that is going to support
them and error out at compile time. The other alternative is to do a
runtime check, but that presents issues for cross-compiling.
Add the pages_[no]huge() functions, which toggle huge page state via
madvise(..., MADV_[NO]HUGEPAGE) calls.
The first time a page run is purged from within an arena chunk, call
pages_nohuge() to tell the kernel to make no further attempts to back
the chunk with huge pages. Upon arena chunk deletion, restore the
associated virtual memory to its original state via pages_huge().
This resolves#243.
The core issue here is the weak linking of the symbol, and in certain
environments--for instance, using the latest Xcode (8.1) with the latest
SDK (10.12)--os_unfair_lock may resolve even though you're compiling on
a host that doesn't support it (10.11).
We can use the availability macros to circumvent this problem, and
detect that we're not compiling for a target that is going to support
them and error out at compile time. The other alternative is to do a
runtime check, but that presents issues for cross-compiling.
Some versions of Android provide a pthreads library without providing
pthread_atfork(), so in practice a separate feature test is necessary
for the latter.
Some versions of Android provide a pthreads library without providing
pthread_atfork(), so in practice a separate feature test is necessary
for the latter.
Add feature tests for the MADV_FREE and MADV_DONTNEED flags to
madvise(2), so that MADV_FREE is detected and used for Linux kernel
versions 4.5 and newer. Refactor pages_purge() so that on systems which
support both flags, MADV_FREE is preferred over MADV_DONTNEED.
This resolves#387.
Add feature tests for the MADV_FREE and MADV_DONTNEED flags to
madvise(2), so that MADV_FREE is detected and used for Linux kernel
versions 4.5 and newer. Refactor pages_purge() so that on systems which
support both flags, MADV_FREE is preferred over MADV_DONTNEED.
This resolves#387.
Rather than relying on two's complement negation for alignment mask
generation, use bitwise not and addition. This dodges warnings from
MSVC, and should be strength-reduced by compiler optimization anyway.
Add extent serial numbers and use them where appropriate as a sort key
that is higher priority than address, so that the allocation policy
prefers older extents.
This resolves#147.
Add extent serial numbers and use them where appropriate as a sort key
that is higher priority than address, so that the allocation policy
prefers older extents.
This resolves#147.
2cdf07aba9 (Fix extent_quantize() to
handle greater-than-huge-size extents.) solved a non-problem; the
expression passed in to index2size() was never too large. However the
expression could in principle underflow, so fix the actual (latent) bug
and remove unnecessary complexity.
Remove outer CHUNK_CEILING(s2u(...)) from alloc_size computation, since
s2u() may overflow (and return 0), and CHUNK_CEILING() is only needed
around the alignment portion of the computation.
This fixes a regression caused by
5707d6f952 (Quantize szad trees by size
class.) and first released in 4.0.0.
This resolves#497.
Allocation requests can't directly create extents that exceed
HUGE_MAXCLASS, but extent merging can create them.
This fixes a regression caused by
8a03cf039c (Implement cache index
randomization for large allocations.) and first released in 4.0.0.
This resolves#497.
