jimzah/openafs
1
0
Fork 0
mirror of https://git.openafs.org/openafs.git synced 2025-01-21 00:10:15 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Windows: refactor cm_GetBuffer avoid BIOD construction

Browse Source 
Constructing a BIOD is a very expensive operation as it requires
obtaining exclusive locks on each and every buffer that in the
collection.  The prior code would construct a BIOD for a chunk
worth of buffers and then check to see if the current buffer is
beyond the serverLength or the truncation position.  If so, the
buffer is cleared and the buffer is returned as current after
releasing the BIOD.  This is very wasteful.  Instead, check every
buffer in the BIOD to see if it should be made current or not.
If yes, do so before releasing the BIOD.  This permits the construction
of the BIOD to be avoided for the rest of the buffers in the chunk.

Change-Id: I0a413f8be9686cd0e326a3ea3608ca954cdf4370
Reviewed-on: http://gerrit.openafs.org/7314
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>
This commit is contained in:
Jeffrey Altman 2012-05-02 17:52:44 -04:00 committed by Jeffrey Altman
parent 6b602e59af
commit a7fec07348
1 changed files with 46 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
src/WINNT/afsd/cm_dcache.c
View File

@ -1701,7 +1701,7 @@ long cm_GetBuffer(cm_scache_t *scp, cm_buf_t *bufp, int *cpffp, cm_user_t *userp
code = cm_SetupFetchBIOD(scp, &bufp->offset, &biod, userp, reqp);
if (code) {
/* couldn't even get the first page setup properly */
osi_Log1(afsd_logp, "GetBuffer: SetupFetchBIOD failure code %d", code);
osi_Log1(afsd_logp, "cm_GetBuffer: SetupFetchBIOD failure code %d", code);
return code;
}
@ -1712,26 +1712,50 @@ long cm_GetBuffer(cm_scache_t *scp, cm_buf_t *bufp, int *cpffp, cm_user_t *userp
* We can lose a race condition and end up with biod.length zero, in
* which case we just retry.
*/
if (bufp->dataVersion <= scp->dataVersion && bufp->dataVersion >= scp->bufDataVersionLow || biod.length == 0) {
if ((bufp->dataVersion == CM_BUF_VERSION_BAD || bufp->dataVersion < scp->bufDataVersionLow) &&
LargeIntegerGreaterThanOrEqualTo(bufp->offset, scp->serverLength))
{
osi_Log4(afsd_logp, "Bad DVs 0x%x != (0x%x -> 0x%x) or length 0x%x",
bufp->dataVersion, scp->bufDataVersionLow, scp->dataVersion, biod.length);
if (bufp->dataVersion == CM_BUF_VERSION_BAD)
memset(bufp->datap, 0, cm_data.buf_blockSize);
bufp->dataVersion = scp->dataVersion;
if (bufp->dataVersion <= scp->dataVersion && bufp->dataVersion >= scp->bufDataVersionLow) {
/* We obtained the buffer while we were waiting */
goto release_biod;
}
if (biod.length == 0) {
osi_Log2(afsd_logp, "cm_GetBuffer BIOD length 0 scp 0x%p bufp 0x%p",
scp, bufp);
code = CM_ERROR_RETRY;
goto release_biod;
}
/* Check for buffers we can fill locally */
for (qdp = biod.bufListEndp;
qdp;
qdp = (osi_queueData_t *) osi_QPrev(&qdp->q)) {
tbufp = osi_GetQData(qdp);
if ( tbufp->dataVersion == CM_BUF_VERSION_BAD ||
tbufp->dataVersion < scp->bufDataVersionLow ||
tbufp->dataVersion > scp->dataVersion) {
osi_Log4(afsd_logp, "cm_GetBuffer bufp 0x%p DVs 0x%x != (0x%x -> 0x%x)",
tbufp, tbufp->dataVersion, scp->bufDataVersionLow, scp->dataVersion);
if (LargeIntegerGreaterThanOrEqualTo(tbufp->offset, scp->length))
{
if (tbufp->dataVersion == CM_BUF_VERSION_BAD)
memset(tbufp->datap, 0, cm_data.buf_blockSize);
tbufp->dataVersion = scp->dataVersion;
}
if ((scp->mask & CM_SCACHEMASK_TRUNCPOS) &&
LargeIntegerGreaterThanOrEqualTo(tbufp->offset, scp->truncPos)) {
memset(tbufp->datap, 0, cm_data.buf_blockSize);
tbufp->dataVersion = scp->dataVersion;
}
}
cm_ReleaseBIOD(&biod, 0, 0, 1);
return 0;
} else if ((bufp->dataVersion == CM_BUF_VERSION_BAD || bufp->dataVersion < scp->bufDataVersionLow)
&& (scp->mask & CM_SCACHEMASK_TRUNCPOS) &&
LargeIntegerGreaterThanOrEqualTo(bufp->offset, scp->truncPos)) {
memset(bufp->datap, 0, cm_data.buf_blockSize);
bufp->dataVersion = scp->dataVersion;
cm_ReleaseBIOD(&biod, 0, 0, 1);
return 0;
}
if (bufp->dataVersion <= scp->dataVersion && bufp->dataVersion >= scp->bufDataVersionLow) {
/* We locally populated the buffer we wanted */
goto release_biod;
}
InterlockedIncrement(&scp->activeRPCs);
@ -1822,7 +1846,8 @@ long cm_GetBuffer(cm_scache_t *scp, cm_buf_t *bufp, int *cpffp, cm_user_t *userp
* the network round trip by allocating zeroed buffers and
* faking the status info.
*/
if (biod.offset.QuadPart >= scp->length.QuadPart) {
if (biod.offset.QuadPart >= scp->serverLength.QuadPart ||
((scp->mask & CM_SCACHEMASK_TRUNCPOS) && biod.offset.QuadPart > scp->truncPos.QuadPart)) {
osi_Log5(afsd_logp, "SKIP FetchData64 scp 0x%p, off 0x%x:%08x > length 0x%x:%08x",
scp, biod.offset.HighPart, biod.offset.LowPart,
scp->length.HighPart, scp->length.LowPart);
@ -2178,6 +2203,7 @@ long cm_GetBuffer(cm_scache_t *scp, cm_buf_t *bufp, int *cpffp, cm_user_t *userp
else
InterlockedDecrement(&scp->activeRPCs);
release_biod:
/* release scatter/gather I/O structure (buffers, locks) */
cm_ReleaseBIOD(&biod, 0, code, 1);