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[t:4181] #4181 Make memory accounting a little cleaner.

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git-svn-id: file:///svn/toku/tokudb@38050 c7de825b-a66e-492c-adef-691d508d4ae1
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Barry Perlman 2013-04-17 00:00:01 -04:00 • committed by Yoni Fogel
parent 8ba797fae1
commit 46e2eba914
2 changed files with 13 additions and 7 deletions
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18
linux/memory.c
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@ -67,14 +67,20 @@ my_malloc_usable_size(void *p) {
return p == NULL ? 0 : malloc_usable_size(p); return p == NULL ? 0 : malloc_usable_size(p);
} }
// max_in_use may be slightly off because use of max_in_use is not thread-safe. // Note that max_in_use may be slightly off because use of max_in_use is not thread-safe.
// It is not worth the overhead to make it completely accurate. // It is not worth the overhead to make it completely accurate, but
// this logic is intended to guarantee that it increases monotonically.
// Note that status.sum_used and status.sum_freed increase monotonically
// and that status.max_in_use is declared volatile.
static inline void static inline void
set_max(uint64_t sum_used, uint64_t sum_freed) { set_max(uint64_t sum_used, uint64_t sum_freed) {
uint64_t in_use = (sum_used - sum_freed); if (sum_used >= sum_freed) {
if ((!(in_use & 0x8000000000000000)) // if wrap due to another thread, ignore bogus "negative" value uint64_t in_use = sum_used - sum_freed;
&& (in_use > status.max_in_use)) { uint64_t old_max;
status.max_in_use = in_use; do {
old_max = status.max_in_use;
} while (old_max < in_use &&
!__sync_bool_compare_and_swap(&status.max_in_use, old_max, in_use));
} }
} }

2
toku_include/memory.h
View file

@ -106,7 +106,7 @@ typedef struct memory_status {
uint64_t requested; // number of bytes requested uint64_t requested; // number of bytes requested
uint64_t used; // number of bytes used (requested + overhead), obtained from malloc_usable_size() uint64_t used; // number of bytes used (requested + overhead), obtained from malloc_usable_size()
uint64_t freed; // number of bytes freed; uint64_t freed; // number of bytes freed;
uint64_t max_in_use; // maximum memory footprint (used - freed), approximate (not worth threadsafety overhead for exact) volatile uint64_t max_in_use; // maximum memory footprint (used - freed), approximate (not worth threadsafety overhead for exact)
const char *mallocator_version; const char *mallocator_version;
uint64_t mmap_threshold; uint64_t mmap_threshold;
} MEMORY_STATUS_S, *MEMORY_STATUS; } MEMORY_STATUS_S, *MEMORY_STATUS;