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Instead of allocating a semaphore from the operating system for every spinlock, allocate a fixed number of semaphores (by default, 1024) from the operating system and multiplex all the spinlocks that get created onto them. This could self-deadlock if a process attempted to acquire more than one spinlock at a time, but since processes aren't supposed to execute anything other than short stretches of straight-line code while holding a spinlock, that shouldn't happen. One motivation for this change is that, with the introduction of dynamic shared memory, it may be desirable to create spinlocks that last for less than the lifetime of the server. Without this change, attempting to use such facilities under --disable-spinlocks would quickly exhaust any supply of available semaphores. Quite apart from that, it's desirable to contain the quantity of semaphores needed to run the server simply on convenience grounds, since using too many may make it harder to get PostgreSQL running on a new platform, which is mostly the point of --disable-spinlocks in the first place. Patch by me; review by Tom Lane. |
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.. | ||
access | ||
bootstrap | ||
catalog | ||
commands | ||
common | ||
datatype | ||
executor | ||
foreign | ||
lib | ||
libpq | ||
mb | ||
nodes | ||
optimizer | ||
parser | ||
port | ||
portability | ||
postmaster | ||
regex | ||
replication | ||
rewrite | ||
snowball | ||
storage | ||
tcop | ||
tsearch | ||
utils | ||
.gitignore | ||
c.h | ||
fmgr.h | ||
funcapi.h | ||
getaddrinfo.h | ||
getopt_long.h | ||
Makefile | ||
miscadmin.h | ||
pg_config_ext.h.in | ||
pg_config_ext.h.win32 | ||
pg_config_manual.h | ||
pg_config.h.in | ||
pg_config.h.win32 | ||
pg_trace.h | ||
pgstat.h | ||
pgtar.h | ||
pgtime.h | ||
port.h | ||
postgres_ext.h | ||
postgres_fe.h | ||
postgres.h | ||
rusagestub.h | ||
windowapi.h |