This change adds tests for the new memory manager code particularly with
its windows support. Function call tracing now works reliably on Silicon
since our function hooker was missing new Apple self-modifying code APIs
Many tests that were disabled a long time ago on aarch64 are reactivated
by this change, now that arm support is on equal terms with x86. There's
been a lot of places where ftrace could cause deadlocks, which have been
hunted down across all platforms thanks to new tests. A bug in Windows's
kill() function has been identified.
This change makes fork() go nearly as fast as sys_fork() on UNIX. As for
Windows this change shaves about 4-5ms off fork() + wait() latency. This
is accomplished by using WriteProcessMemory() from the parent process to
setup the address space of a suspended process; it is better than a pipe
This change fixes a bug where nsync waiter objects would leak. It'd mean
that long-running programs like runitd would run out of file descriptors
on NetBSD where waiter objects have ksem file descriptors. On other OSes
this bug is mostly harmless since the worst that can happen with a futex
is to leak a little bit of ram. The bug was caused because tib_nsync was
sneaking back in after the finalization code had cleared it. This change
refactors the thread exiting code to handle nsync teardown appropriately
and in making this change I found another issue, which is that user code
which is buggy, and tries to exit without joining joinable threads which
haven't been detached, would result in a deadlock. That doesn't sound so
bad, except the main thread is a joinable thread. So this deadlock would
be triggered in ways that put libc at fault. So we now auto-join threads
and libc will log a warning to --strace when that happens for any thread
On Windows, mmap() now chooses addresses transactionally. It reduces the
risk of badness when interacting with the WIN32 memory manager. We don't
throw darts anymore. There is also no more retry limit, since we recover
from mystery maps more gracefully. The subroutine for combining adjacent
maps has been rewritten for clarity. The print maps subroutine is better
This change goes to great lengths to perfect the stack overflow code. On
Windows you can now longjmp() out of a crash signal handler. Guard pages
previously weren't being restored properly by the signal handler. That's
fixed, so on Windows you can now handle a stack overflow multiple times.
Great thought has been put into selecting the perfect SIGSTKSZ constants
so you can save sigaltstack() memory. You can now use kprintf() with 512
bytes of stack available. The guard pages beneath the main stack are now
recorded in the memory manager.
This change fixes getcontext() so it works right with the %rax register.
This change introduces a new deadlock detector for Cosmo's POSIX threads
implementation. Error check mutexes will now track a DAG of nested locks
and report EDEADLK when a deadlock is theoretically possible. These will
occur rarely, but it's important for production hardening your code. You
don't even need to change your mutexes to use the POSIX error check mode
because `cosmocc -mdbg` will enable error checking on mutexes by default
globally. When cycles are found, an error message showing your demangled
symbols describing the strongly connected component are printed and then
the SIGTRAP is raised, which means you'll also get a backtrace if you're
using ShowCrashReports() too. This new error checker is so low-level and
so pure that it's able to verify the relationships of every libc runtime
lock, including those locks upon which the mutex implementation depends.
Cosmopolitan now supports mremap(), which is only supported on Linux and
NetBSD. First, it allows memory mappings to be relocated without copying
them; this can dramatically speed up data structures like std::vector if
the array size grows larger than 256kb. The mremap() system call is also
10x faster than munmap() when shrinking large memory mappings.
There's now two functions, getpagesize() and getgransize() which help to
write portable code that uses mmap(MAP_FIXED). Alternative sysconf() may
be called with our new _SC_GRANSIZE. The madvise() system call now has a
better wrapper with improved documentation.
It's now possible to create thousands of thousands of sparse independent
memory mappings, without any slowdown. The memory manager is better with
tracking memory protection now, particularly on Windows in a precise way
that can be restored during fork(). You now have the highest quality mem
manager possible. It's even better than some OSes like XNU, where mmap()
is implemented as an O(n) operation which means sadly things aren't much
improved over there. With this change the llamafile HTTP server endpoint
at /tokenize with a prompt of 50 tokens is now able to handle 2.6m r/sec
This change reduces o/tiny/examples/life from 44kb to 24kb in size since
it avoids linking mmap() when unnecessary. This is important, to helping
cosmo not completely lose touch with its roots.
This fixes a regression in mmap(MAP_FIXED) on Windows caused by a recent
revision. This change also fixes ZipOS so it no longer needs a MAP_FIXED
mapping to open files from the PKZIP store. The memory mapping mutex was
implemented incorrectly earlier which meant that ftrace and strace could
cause cause crashes. This lock and other recursive mutexes are rewritten
so that it should be provable that recursive mutexes in cosmopolitan are
asynchronous signal safe.
Actually Portable Executable now supports Android. Cosmo's old mmap code
required a 47 bit address space. The new implementation is very agnostic
and supports both smaller address spaces (e.g. embedded) and even modern
56-bit PML5T paging for x86 which finally came true on Zen4 Threadripper
Cosmopolitan no longer requires UNIX systems to observe the Windows 64kb
granularity; i.e. sysconf(_SC_PAGE_SIZE) will now report the host native
page size. This fixes a longstanding POSIX conformance issue, concerning
file mappings that overlap the end of file. Other aspects of conformance
have been improved too, such as the subtleties of address assignment and
and the various subtleties surrounding MAP_FIXED and MAP_FIXED_NOREPLACE
On Windows, mappings larger than 100 megabytes won't be broken down into
thousands of independent 64kb mappings. Support for MAP_STACK is removed
by this change; please use NewCosmoStack() instead.
Stack overflow avoidance is now being implemented using the POSIX thread
APIs. Please use GetStackBottom() and GetStackAddr(), instead of the old
error-prone GetStackAddr() and HaveStackMemory() APIs which are removed.
