Commit Graph

11 Commits

Author SHA1 Message Date
Sam Gross 412920a41e
gh-112532: Improve mimalloc page visiting (#114133)
This adds support for visiting abandoned pages in mimalloc and improves
the performance of the page visiting code. Abandoned pages contain
memory blocks from threads that have exited. At some point, they may be
later reclaimed by other threads. We still need to visit those pages in
the free-threaded GC because they contain live objects.

This also reduces the overhead of visiting mimalloc pages:

 * Special cases for full, empty, and pages containing only a single
   block.
 * Fix free_map to use one bit instead of one byte per block.
 * Use fast integer division by a constant algorithm when computing
   block offset from block size and index.
2024-01-22 13:10:21 -08:00
Jakub Kulík 10d3f04aec
gh-112808: Fix mimalloc build on Solaris (#112809) 2024-01-08 15:50:56 -08:00
Jakub Kulík ae968d1032
gh-112806: Remove unused function warnings during mimalloc build on Solaris (#112807) 2024-01-08 15:49:33 -08:00
Sam Gross 0b7476080b
gh-112532: Tag mimalloc heaps and pages (#113742)
* gh-112532: Tag mimalloc heaps and pages

Mimalloc pages are data structures that contain contiguous allocations
of the same block size. Note that they are distinct from operating
system pages. Mimalloc pages are contained in segments.

When a thread exits, it abandons any segments and contained pages that
have live allocations. These segments and pages may be later reclaimed
by another thread. To support GC and certain thread-safety guarantees in
free-threaded builds, we want pages to only be reclaimed by the
corresponding heap in the claimant thread. For example, we want pages
containing GC objects to only be claimed by GC heaps.

This allows heaps and pages to be tagged with an integer tag that is
used to ensure that abandoned pages are only claimed by heaps with the
same tag. Heaps can be initialized with a tag (0-15); any page allocated
by that heap copies the corresponding tag.

* Fix conversion warning
2024-01-05 12:08:50 -08:00
Sam Gross fcb3c2a444
gh-112532: Isolate abandoned segments by interpreter (#113717)
* gh-112532: Isolate abandoned segments by interpreter

Mimalloc segments are data structures that contain memory allocations along
with metadata. Each segment is "owned" by a thread. When a thread exits,
it abandons its segments to a global pool to be later reclaimed by other
threads. This changes the pool to be per-interpreter instead of process-wide.

This will be important for when we use mimalloc to find GC objects in the
`--disable-gil` builds. We want heaps to only store Python objects from a
single interpreter. Absent this change, the abandoning and reclaiming process
could break this isolation.

* Add missing '&_mi_abandoned_default' to 'tld_empty'
2024-01-04 22:21:40 +00:00
Sam Gross acf3bcc886
gh-112532: Use separate mimalloc heaps for GC objects (gh-113263)
* gh-112532: Use separate mimalloc heaps for GC objects

In `--disable-gil` builds, we now use four separate heaps in
anticipation of using mimalloc to find GC objects when the GIL is
disabled. To support this, we also make a few changes to mimalloc:

* `mi_heap_t` and `mi_tld_t` initialization is split from allocation.
  This allows us to have a `mi_tld_t` per-`PyThreadState`, which is
  important to keep interpreter isolation, since the same OS thread may
  run in multiple interpreters (using different PyThreadStates.)

* Heap abandoning (mi_heap_collect_ex) can now be called from a
  different thread than the one that created the heap. This is necessary
  because we may clear and delete the containing PyThreadStates from a
  different thread during finalization and after fork().

* Use enum instead of defines and guard mimalloc includes.

* The enum typedef will be convenient for future PRs that use the type.
* Guarding the mimalloc includes allows us to unconditionally include
  pycore_mimalloc.h from other header files that rely on things like
  `struct _mimalloc_thread_state`.

* Only define _mimalloc_thread_state in Py_GIL_DISABLED builds
2023-12-27 01:53:20 +09:00
Sam Gross 9afb0e1606
gh-112027: Don't print mimalloc warning after mmap() call (gh-113372)
gh-112027: Don't print mimalloc warning after mmap

This changes the warning to a "verbose"-level message in prim.c. The
address passed to mmap is only a hint -- it's normal for mmap() to
sometimes not respect the hint and return a different address.
2023-12-22 09:38:27 +09:00
Furkan Onder 0ff6368519
gh-111906: Fix warnings during mimalloc build on FreeBSD (#111907)
Fix `unused function` warnings during mimalloc build on FreeBSD.
2023-11-14 17:07:46 +01:00
Ayappan Perumal 794dff2fb1
gh-111544: Fix mimalloc build on AIX (#111593) 2023-11-02 08:01:50 +01:00
Victor Stinner 1673e44017
gh-90815: Fix mimalloc build on WASI (#111524)
Include <unistd.h> to get sbrk() function.
2023-10-30 23:10:22 +01:00
Dino Viehland 05f2f0ac92
gh-90815: Add mimalloc memory allocator (#109914)
* Add mimalloc v2.12

Modified src/alloc.c to remove include of alloc-override.c and not
compile new handler.

Did not include the following files:

 - include/mimalloc-new-delete.h
 - include/mimalloc-override.h
 - src/alloc-override-osx.c
 - src/alloc-override.c
 - src/static.c
 - src/region.c

mimalloc is thread safe and shares a single heap across all runtimes,
therefore finalization and getting global allocated blocks across all
runtimes is different.

* mimalloc: minimal changes for use in Python:

 - remove debug spam for freeing large allocations
 - use same bytes (0xDD) for freed allocations in CPython and mimalloc
   This is important for the test_capi debug memory tests

* Don't export mimalloc symbol in libpython.
* Enable mimalloc as Python allocator option.
* Add mimalloc MIT license.
* Log mimalloc in Lib/test/pythoninfo.py.
* Document new mimalloc support.
* Use macro defs for exports as done in:
  https://github.com/python/cpython/pull/31164/

Co-authored-by: Sam Gross <colesbury@gmail.com>
Co-authored-by: Christian Heimes <christian@python.org>
Co-authored-by: Victor Stinner <vstinner@python.org>
2023-10-30 15:43:11 +00:00