pgsql: bufmgr: Make buffer hit helper

bufmgr: Make buffer hit helper

Already two places count buffer hits, requiring quite a few lines of
code since we do accounting in so many places. Future commits will add
more locations, so refactor into a helper.

Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Nazir Bilal Yavuz <byavuz81@gmail.com>
Discussion: https://postgr.es/m/zljergweqti7x67lg5ije2rzjusie37nslsnkjkkby4laqqbfw@3p3zu522yykv

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/df09452c3209d542a19b9c4afa7a18c656cb4a80

Modified Files
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src/backend/storage/buffer/bufmgr.c | 84 ++++++++++++++++++-------------------
1 file changed, 42 insertions(+), 42 deletions(-)