database/postgres
database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-05-02 11:44:50 +03:00
Code

Further effort at preventing memory map dump from affecting the results.

Browse Source 
Rather than elog'ing immediately, push the map data into a preallocated
StringInfo.  Perhaps this will prevent some of the mid-operation
allocations that are evidently happening now.

Discussion: https://postgr.es/m/25495.1524517820@sss.pgh.pa.us
This commit is contained in:
Tom Lane 2018-04-30 16:19:51 -04:00
parent b04ebca6cd
commit ce07aff48f
1 changed files with 23 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
src/backend/port/win32_shmem.c
View File

@ -12,6 +12,7 @@
*/
#include "postgres.h"
#include "lib/stringinfo.h"
#include "miscadmin.h"
#include "storage/dsm.h"
#include "storage/ipc.h"
@ -54,13 +55,17 @@ mi_state(DWORD code)
return "???";
}
/*
* Append memory dump to buf. To avoid affecting the memory map mid-run,
* buf should be preallocated to be bigger than needed.
*/
static void
dumpmem(const char *reason)
dumpmem(StringInfo buf, const char *reason)
{
char *addr = 0;
MEMORY_BASIC_INFORMATION mi;
elog(LOG, "%s memory map", reason);
appendStringInfo(buf, "%s memory map:", reason);
do
{
memset(&mi, 0, sizeof(mi));
@ -68,12 +73,13 @@ dumpmem(const char *reason)
{
if (GetLastError() == ERROR_INVALID_PARAMETER)
break;
elog(LOG, "VirtualQuery failed: %lu", GetLastError());
appendStringInfo(buf, "\nVirtualQuery failed: %lu", GetLastError());
break;
}
elog(LOG, "0x%p+0x%p %s (alloc 0x%p) %s",
mi.BaseAddress, (void *) mi.RegionSize,
mi_type(mi.Type), mi.AllocationBase, mi_state(mi.State));
appendStringInfo(buf, "\n0x%p+0x%p %s (alloc 0x%p) %s",
mi.BaseAddress, (void *) mi.RegionSize,
mi_type(mi.Type), mi.AllocationBase,
mi_state(mi.State));
addr += mi.RegionSize;
} while (addr > 0);
}
@ -442,11 +448,16 @@ PGSharedMemoryReAttach(void)
{
PGShmemHeader *hdr;
void *origUsedShmemSegAddr = UsedShmemSegAddr;
StringInfoData buf;
Assert(UsedShmemSegAddr != NULL);
Assert(IsUnderPostmaster);
dumpmem("before VirtualFree");
/* Ensure buf is big enough that it won't grow mid-operation */
initStringInfo(&buf);
enlargeStringInfo(&buf, 128 * 1024);
dumpmem(&buf, "before VirtualFree");
/*
* Release memory region reservation that was made by the postmaster
@ -455,20 +466,19 @@ PGSharedMemoryReAttach(void)
elog(FATAL, "failed to release reserved memory region (addr=%p): error code %lu",
UsedShmemSegAddr, GetLastError());
dumpmem("after VirtualFree");
dumpmem(&buf, "after VirtualFree");
hdr = (PGShmemHeader *) MapViewOfFileEx(UsedShmemSegID, FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, 0, UsedShmemSegAddr);
if (!hdr)
{
DWORD maperr = GetLastError();
dumpmem("after failed MapViewOfFileEx");
dumpmem(&buf, "after failed MapViewOfFileEx");
elog(LOG, "%s", buf.data);
elog(FATAL, "could not reattach to shared memory (key=%p, addr=%p): error code %lu",
UsedShmemSegID, UsedShmemSegAddr, maperr);
}
else
dumpmem("after MapViewOfFileEx");
if (hdr != origUsedShmemSegAddr)
elog(FATAL, "reattaching to shared memory returned unexpected address (got %p, expected %p)",
hdr, origUsedShmemSegAddr);
@ -476,6 +486,8 @@ PGSharedMemoryReAttach(void)
elog(FATAL, "reattaching to shared memory returned non-PostgreSQL memory");
dsm_set_control_handle(hdr->dsm_control);
pfree(buf.data);
UsedShmemSegAddr = hdr; /* probably redundant */
}