my_large_malloc() attempted large pages whenever --large-pages was
enabled, silently rounding the size up and reporting it back via an
in/out parameter. ut_malloc_dontdump() never passed that adjusted
size on to its own callers (the InnoDB redo log buffer and
recv_sys_t::tmp_buf), so freeing later used the original, smaller
size, causing the reported "faux memory leak".
Only the buffer pool and the MyISAM/Aria key caches are documented
to benefit from large pages. Everything else that ended up calling
my_large_malloc() only wanted its "do not dump to core" property and
picked up large pages as an undocumented side effect; those buffers
are also small and sequentially accessed, so they would have gained
little from large pages anyway.
Add MY_TRY_LARGE_PAGES: my_large_malloc() and my_large_virtual_alloc()
now only attempt large pages when a caller passes this flag, instead
of always trying whenever the global option is set. Only the buffer
pool and the key caches pass it. The redo log buffer, tmp_buf, and
row0log.cc's crypt buffers no longer request large pages at all,
which removes the size-rounding bug for them without touching that
code.
my_large_virtual_alloc()'s fallback (no usable large page size) must
also return read-write memory right away, like the Windows large-pages
fallback already does, since my_virtual_mem_commit() is a no-op for
MY_TRY_LARGE_PAGES. my_large_pages_flag is now set once, in
my_init_large_pages(), and never changed thereafter, on any platform.
Both my_virtual_mem_commit() and my_virtual_mem_decommit() are now
no-ops, aside from accounting, whenever large pages are requested.
Also fix a broken mtr suppression regex in main.large_pages that
would fail the test on Windows.
6ab0036cf3