database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-27 23:21:58 +03:00
Code Activity

Avoid allocations in critical sections.

Browse Source 
If a palloc in a critical section fails, it becomes a PANIC.
This commit is contained in:
Heikki Linnakangas
2014-04-04 13:12:38 +03:00
parent d359f71ac0
commit 1891a4b6b8
4 changed files with 49 additions and 57 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
src/backend/access/transam/xlog.c
View File

@ -739,9 +739,8 @@ XLogInsert(RmgrId rmid, uint8 info, XLogRecData *rdata)
if (rechdr == NULL)
{
rechdr = malloc(SizeOfXLogRecord);
if (rechdr == NULL)
elog(ERROR, "out of memory");
static char rechdrbuf[SizeOfXLogRecord + MAXIMUM_ALIGNOF];
rechdr = (XLogRecord *) MAXALIGN(&rechdrbuf);
MemSet(rechdr, 0, SizeOfXLogRecord);
}
@ -2248,6 +2247,7 @@ XLogFileInit(XLogSegNo logsegno, bool *use_existent, bool use_lock)
{
char path[MAXPGPATH];
char tmppath[MAXPGPATH];
char zbuffer_raw[BLCKSZ + MAXIMUM_ALIGNOF];
char *zbuffer;
XLogSegNo installed_segno;
int max_advance;
@ -2286,16 +2286,6 @@ XLogFileInit(XLogSegNo logsegno, bool *use_existent, bool use_lock)
unlink(tmppath);
/*
* Allocate a buffer full of zeros. This is done before opening the file
* so that we don't leak the file descriptor if palloc fails.
*
* Note: palloc zbuffer, instead of just using a local char array, to
* ensure it is reasonably well-aligned; this may save a few cycles
* transferring data to the kernel.
*/
zbuffer = (char *) palloc0(XLOG_BLCKSZ);
/* do not use get_sync_bit() here --- want to fsync only at end of fill */
fd = BasicOpenFile(tmppath, O_RDWR | O_CREAT | O_EXCL | PG_BINARY,
S_IRUSR | S_IWUSR);
@ -2312,7 +2302,12 @@ XLogFileInit(XLogSegNo logsegno, bool *use_existent, bool use_lock)
* fsync below) that all the indirect blocks are down on disk. Therefore,
* fdatasync(2) or O_DSYNC will be sufficient to sync future writes to the
* log file.
*
* Note: ensure the buffer is reasonably well-aligned; this may save a few
* cycles transferring data to the kernel.
*/
zbuffer = (char *) MAXALIGN(zbuffer_raw);
memset(zbuffer, 0, BLCKSZ);
for (nbytes = 0; nbytes < XLogSegSize; nbytes += XLOG_BLCKSZ)
{
errno = 0;
@ -2335,7 +2330,6 @@ XLogFileInit(XLogSegNo logsegno, bool *use_existent, bool use_lock)
errmsg("could not write to file \"%s\": %m", tmppath)));
}
}
pfree(zbuffer);
if (pg_fsync(fd) != 0)
{