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The freespace calculations were double counting the new slot's header.

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This commit is contained in:
Sears Russell 2006-03-28 21:21:47 +00:00
parent ced022d0fe
commit 3c55daede9
1 changed files with 19 additions and 12 deletions
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31
src/lladd/page/slotted.c
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@ -138,20 +138,25 @@ void slottedPageInitialize(Page * page) {
} }
/** @todo Implement a model of slotted pages in the test scripts, and
then write a randomized test that confirms the model matches the
implementation's behavior. */
size_t slottedFreespaceUnlocked(Page * page) { size_t slottedFreespaceUnlocked(Page * page) {
/* @todo I'm unsure these variable names are actually acurrate... */ // end_of_free_space points to the beginning of the next slot header (if we were to allocate one)
size_t end_of_free_space = (size_t)slot_length_ptr(page, *numslots_ptr(page)); byte* end_of_free_space = (byte*)slot_length_ptr(page, *numslots_ptr(page)-1);
size_t start_of_free_space = (size_t)(page->memAddr + *freespace_ptr(page)); // start_of_free_space points to the first unallocated byte in the page
// assert( (slot_length_ptr(page, *numslots_ptr(page))) >= (((size_t)(page->memAddr + *freespace_ptr(page))) + SLOTTED_PAGE_OVERHEAD_PER_RECORD)); // (ignoring space that could be reclaimed by compaction)
assert(end_of_free_space >= start_of_free_space); byte* start_of_free_space = (byte*)(page->memAddr + *freespace_ptr(page));
if(end_of_free_space - start_of_free_space <= SLOTTED_PAGE_OVERHEAD_PER_RECORD) { // We need the "+ SLOTTED_PAGE_OVERHEAD_PER_RECORD" because the regions they cover could overlap.
return 0; assert(end_of_free_space + SLOTTED_PAGE_OVERHEAD_PER_RECORD >= start_of_free_space);
} else {
return end_of_free_space - start_of_free_space - SLOTTED_PAGE_OVERHEAD_PER_RECORD;
}
// size_t ret = ((size_t)slot_length_ptr(page, *numslots_ptr(page)) - (size_t)(page->memAddr + *freespace_ptr(page))) - SLOTTED_PAGE_OVERHEAD_PER_RECORD; if(end_of_free_space < start_of_free_space) {
//return ret; // The regions overlap; there is no free space.
return 0;
} else {
// The regions do not overlap. There might be free space.
return (size_t) (end_of_free_space - start_of_free_space);
}
} }
@ -302,6 +307,8 @@ static void __really_do_ralloc(Page * page, recordid rid) {
slottedCompact(page); slottedCompact(page);
/* Make sure there's enough free space... */ /* Make sure there's enough free space... */
// DELETE NEXT LINE
int size = slottedFreespaceUnlocked(page);
assert (slottedFreespaceUnlocked(page) >= rid.size); assert (slottedFreespaceUnlocked(page) >= rid.size);
} }