From 4f1f5a7f85cee932c417aef589b27574813a06c9 Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Fri, 22 Jul 2022 09:41:12 +1200 Subject: Remove fls(), use pg_leftmost_one_pos32() instead. Commit 4f658dc8 provided the traditional BSD fls() function in src/port/fls.c so it could be used in several places. Later we added a bunch of similar facilities in pg_bitutils.h, based on compiler builtins that map to hardware instructions. It's a bit confusing to have both 1-based and 0-based variants of this operation in use in different parts of the tree, and neither is blessed by a standard. Let's drop fls.c and the configure probe, and reuse the newer code. Reviewed-by: David Rowley Reviewed-by: Tom Lane Discussion: https://postgr.es/m/CA%2BhUKG%2B7dSX1XF8yFGmYk-%3D48dbjH2kmzZj16XvhbrWP-9BzRg%40mail.gmail.com --- src/backend/utils/mmgr/dsa.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) (limited to 'src/backend/utils/mmgr/dsa.c') diff --git a/src/backend/utils/mmgr/dsa.c b/src/backend/utils/mmgr/dsa.c index b6cb8fa13dc..82376fde2d9 100644 --- a/src/backend/utils/mmgr/dsa.c +++ b/src/backend/utils/mmgr/dsa.c @@ -51,6 +51,7 @@ #include "postgres.h" #include "port/atomics.h" +#include "port/pg_bitutils.h" #include "storage/dsm.h" #include "storage/ipc.h" #include "storage/lwlock.h" @@ -137,7 +138,18 @@ typedef size_t dsa_segment_index; * free pages? There is no point in looking in segments in lower bins; they * definitely can't service a request for n free pages. */ -#define contiguous_pages_to_segment_bin(n) Min(fls(n), DSA_NUM_SEGMENT_BINS - 1) +static inline size_t +contiguous_pages_to_segment_bin(size_t n) +{ + size_t bin; + + if (n == 0) + bin = 0; + else + bin = pg_leftmost_one_pos_size_t(n) + 1; + + return Min(bin, DSA_NUM_SEGMENT_BINS - 1); +} /* Macros for access to locks. */ #define DSA_AREA_LOCK(area) (&area->control->lock) -- cgit v1.2.3