The Fast allocators mechanism is implemented by ProxyAllocator.
There are 2 config options in record.config:
proxy.config.allocator.thread_freelist_size (I_ProxyAllocator.h:extern int
thread_freelist_high_watermark;)
proxy.config.allocator.thread_freelist_low_watermark
(I_ProxyAllocator.h:extern int thread_freelist_low_watermark;)
according to the code in I_ProxyAllocator.h:
126 #define THREAD_FREE(_p, _a, _t) \
127 do { \
128 *(char **)_p = (char *)_t->_a.freelist; \
129 _t->_a.freelist = _p; \
130 _t->_a.allocated++; \
131 if (_t->_a.allocated > thread_freelist_high_watermark) \
132 thread_freeup(::_a, _t->_a); \
133 } while (0)
One EThread can not keeps more than thread_freelist_high_watermark number
of object in Fast Allocators.
And keeps at least thread_freelist_low_watermark number of object in Fast
Allocators.
97 template <class C>
98 inline void
99 thread_freeup(ClassAllocator<C> &a, ProxyAllocator &l)
100 {
101 C *head = (C *)l.freelist;
102 C *tail = (C *)l.freelist;
103 size_t count = 0;
104 while (l.freelist && l.allocated > thread_freelist_low_watermark) {
105 tail = (C *)l.freelist;
106 l.freelist = *(C **)l.freelist;
107 --(l.allocated);
108 ++count;
109 }
110
111 if (unlikely(count == 1)) {
112 a.free(tail);
113 } else if (count > 0) {
114 a.free_bulk(head, tail, count);
115 }
116
117 ink_assert(l.allocated >= thread_freelist_low_watermark);
118 }
With these 2 options, you can reduce the memory used by Fast Allocators.
You should be aware of keeping thread_freelist_low_watermark less than
thread_freelist_high_waterma
2016-12-20 4:19 GMT+08:00 Vamsi Ambati <[email protected]>:
> DevOps is complaining about the excessive memory usage of ATS 7.0, in
> this process just noticed a comment in one of the source file(Allocator.h)
>
> " @note Fast allocators could accumulate a lot of objects in the
> free pool as a result of bursty demand. Memory used by the objects
> in the free pool never gets freed even if the freelist grows very
> large.”
>
> My question is, if the above comment is right ,are there any caps/limits
> to control the growth of this free list ?? If so, Could some one Please
> share ?
> We are running ATS 7.0 on VMs with 4GB/8GB RAM and ram cache is
> configured to 48MB .
>
>
> Vamsi
