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Windows: remove CM_BUF_CMBKGFETCH flag

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The processing of the CM_BUF_CMBKGFETCH flag adds more
overhead than it prevents.  Get rid of it.

LICENSE MIT

Change-Id: Ic152707fd3f0a7592409a5f570c02488f5503a9c
Reviewed-on: http://gerrit.openafs.org/5359
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Tested-by: Jeffrey Altman <jaltman@openafs.org>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
This commit is contained in:
Jeffrey Altman 2009-12-14 13:33:02 -05:00 committed by Jeffrey Altman
parent 33af0f92e9
commit b6f23864ff
2 changed files with 1 additions and 44 deletions
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2
src/WINNT/afsd/cm_buf.h
View File

@ -95,8 +95,6 @@ typedef struct cm_buf {
#define CM_BUF_CMSTORING 2 /* storing this buffer */
#define CM_BUF_CMFULLYFETCHED 4 /* read-while-fetching optimization */
#define CM_BUF_CMWRITING 8 /* writing to this buffer */
#define CM_BUF_CMBKGFETCH 16 /* background fetch queued by
* prefetch or redirector */
/* waiting is done based on scp->flags. Removing bits from cmFlags
should be followed by waking the scp. */

43
src/WINNT/afsd/cm_dcache.c
View File

@ -690,7 +690,7 @@ cm_CheckFetchRange(cm_scache_t *scp, osi_hyper_t *startBasep, osi_hyper_t *lengt
bp = buf_Find(&scp->fid, &tbase);
/* We cheat slightly by not locking the bp mutex. */
if (bp) {
if ((bp->cmFlags & (CM_BUF_CMFETCHING | CM_BUF_CMSTORING | CM_BUF_CMBKGFETCH)) == 0
if ((bp->cmFlags & (CM_BUF_CMFETCHING | CM_BUF_CMSTORING)) == 0
&& (bp->dataVersion < scp->bufDataVersionLow || bp->dataVersion > scp->dataVersion))
stop = 1;
buf_Release(bp);
@ -843,7 +843,6 @@ cm_BkgPrefetch(cm_scache_t *scp, afs_uint32 p1, afs_uint32 p2, afs_uint32 p3, af
lock_ObtainWrite(&scp->rw);
rxheld = 1;
}
_InterlockedAnd(&bp->cmFlags, ~CM_BUF_CMBKGFETCH);
buf_Release(bp);
bp = NULL;
continue;
@ -858,7 +857,6 @@ cm_BkgPrefetch(cm_scache_t *scp, afs_uint32 p1, afs_uint32 p2, afs_uint32 p3, af
if (code == 0)
fetched = LargeIntegerAdd(fetched, tblocksize);
buf_Release(bp);
_InterlockedAnd(&bp->cmFlags, ~CM_BUF_CMBKGFETCH);
}
if (!rxheld) {
@ -866,17 +864,6 @@ cm_BkgPrefetch(cm_scache_t *scp, afs_uint32 p1, afs_uint32 p2, afs_uint32 p3, af
rxheld = 1;
}
/* Clear flag from any remaining buffers */
for ( ;
LargeIntegerLessThan(offset, end);
offset = LargeIntegerAdd(offset, tblocksize) )
{
bp = buf_Find(scp, &offset);
if (bp) {
_InterlockedAnd(&bp->cmFlags, ~CM_BUF_CMBKGFETCH);
buf_Release(bp);
}
}
cm_ClearPrefetchFlag(LargeIntegerGreaterThanZero(fetched) ? 0 : code,
scp, &base, &fetched);
@ -906,9 +893,7 @@ void cm_ConsiderPrefetch(cm_scache_t *scp, osi_hyper_t *offsetp, afs_uint32 coun
osi_hyper_t readBase;
osi_hyper_t readLength;
osi_hyper_t readEnd;
osi_hyper_t offset;
osi_hyper_t tblocksize; /* a long long temp variable */
cm_buf_t *bp;
tblocksize = ConvertLongToLargeInteger(cm_data.buf_blockSize);
@ -944,32 +929,6 @@ void cm_ConsiderPrefetch(cm_scache_t *scp, osi_hyper_t *offsetp, afs_uint32 coun
readEnd = LargeIntegerAdd(realBase, readLength);
/*
* Mark each buffer in the range as queued for a
* background fetch
*/
for ( offset = realBase;
LargeIntegerLessThan(offset, readEnd);
offset = LargeIntegerAdd(offset, tblocksize) )
{
if (rwheld) {
lock_ReleaseWrite(&scp->rw);
rwheld = 0;
}
bp = buf_Find(scp, &offset);
if (!bp)
continue;
if (!rwheld) {
lock_ObtainWrite(&scp->rw);
rwheld = 1;
}
_InterlockedOr(&bp->cmFlags, CM_BUF_CMBKGFETCH);
buf_Release(bp);
}
if (rwheld)
lock_ReleaseWrite(&scp->rw);