On Windows, a worker process does not call ngx_slab_init() from
ngx_init_zone_pool(), so ngx_slab_max_size, ngx_slab_exact_size,
and ngx_slab_exact_shift were left uninitialized.
Notably, on ppc64 with 64k pagesize, slab 0 (of size 8) requires
128 64-bit elements for bitmasks. The code bogusly assumed that
one uintptr_t is enough for bitmasks plus at least one free slot.
There are lots of C4244 warnings (conversion from 'type1' to 'type2',
possible loss of data), so they were disabled.
The same applies to C4267 warnings (conversion from 'size_t' to 'type',
possible loss of data), most notably - conversion from ngx_str_t.len to
ngx_variable_value_t.len (which is unsigned:28). Additionally, there
is at least one case when it is not possible to fix the warning properly
without introducing win32-specific code: recv() on win32 uses "int len",
while POSIX defines "size_t len".
The ssize_t type now properly defined for 64-bit compilation with MSVC.
Caught by warning C4305 (truncation from '__int64' to 'ssize_t'), on
"cutoff = NGX_MAX_SIZE_T_VALUE / 10" in ngx_atosz()).
Several C4334 warnings (result of 32-bit shift implicitly converted to 64 bits)
were fixed by adding explicit conversions.
Several C4214 warnings (nonstandard extension used: bit field types other
than int) in ngx_http_script.h fixed by changing bit field types from
uintptr_t to unsigned.
Removed code that would cause an endless loop, and removed condition
check that is always false. The first page in the slot list is
guaranteed to satisfy an allocation.
Large allocations from a slab pool result in free page blocks being fragmented,
eventually leading to a situation when no further allocation larger than a page
size are possible from the pool. While this isn't a problem for nginx itself,
it is known to be bad for various 3rd party modules. Fix is to merge adjacent
blocks of free pages in the ngx_slab_free_pages() function.
Prodded by Wandenberg Peixoto and Yichun Zhang.
The flag allows to suppress "ngx_slab_alloc() failed: no memory" messages
from a slab allocator, e.g., if an LRU expiration is used by a consumer
and allocation failures aren't fatal.
The flag is now used in the SSL session cache code, and in the limit_req
module.
Casts between pointers and integers produce warnings on size mismatch. To
silence them, cast to (u)intptr_t should be used. Prevoiusly, casts to
ngx_(u)int_t were used in some cases, and several ngx_int_t expressions had
no casts.
As of now it's mostly style as ngx_int_t is defined as intptr_t.
