Re: DSA failed to allocate memory - Mailing list pgsql-hackers

From Dongming Liu
Subject Re: DSA failed to allocate memory
Date
Msg-id CAL1p7e_cP9yBE2xbrXXqG4aVGs2d_TQ_WuW7JH9g1RrX-yUV_A@mail.gmail.com
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In response to Re: DSA failed to allocate memory  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: DSA failed to allocate memory  (Dongming Liu <ldming101@gmail.com>)
List pgsql-hackers
So it's OK for a segment to be in a bin that suggests that it has more
consecutive free pages than it really does. But it's NOT ok for a
segment to be in a bin that suggests it has fewer consecutive pages
than it really does. If dsa_free() is putting things back into the
wrong place, that's what we need to fix.

I'm trying to move segments into appropriate bins in dsa_free().
In 0001-Re-bin-segment-when-dsa-memory-is-freed.patch, I extract 
the re-bin segment logic into a separate function called rebin_segment,
call it to move the segment to the appropriate bin when dsa memory is
freed. Otherwise, when allocating memory, due to the segment with
enough contiguous pages is in a smaller bin, a suitable segment
may not be found to allocate memory.

Fot test, I port the test_dsa patch from [1] and add an OOM case to
test memory allocation until OOM, free and then allocation, compare 
the number of allocated memory before and after.

Any thoughts?


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