diff options
| author | Thomas Munro <tmunro@postgresql.org> | 2022-07-22 09:41:12 +1200 |
|---|---|---|
| committer | Thomas Munro <tmunro@postgresql.org> | 2022-07-22 10:41:50 +1200 |
| commit | 4f1f5a7f85cee932c417aef589b27574813a06c9 (patch) | |
| tree | 0a9b86ad582917b9ed8c31199f3ae8dca5b9b38c /src/backend/utils/mmgr/dsa.c | |
| parent | 3225399021b62cda66012b17ee60c7bec4733fce (diff) | |
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 <dgrowleyml@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CA%2BhUKG%2B7dSX1XF8yFGmYk-%3D48dbjH2kmzZj16XvhbrWP-9BzRg%40mail.gmail.com
Diffstat (limited to 'src/backend/utils/mmgr/dsa.c')
| -rw-r--r-- | src/backend/utils/mmgr/dsa.c | 14 |
1 files changed, 13 insertions, 1 deletions
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) |