From: ori@eigenstate.org
To: 9front@9front.org
Subject: [9front] git: improvements for packfile caching
Date: Thu, 25 Nov 2021 19:17:12 -0500 [thread overview]
Message-ID: <CCA70C5E32D86D284233DF3314B3322B@eigenstate.org> (raw)
currently the packfile caching in git9 is
wrong: it should keep the pack open in
closepack(), and should use a more
comprehensive check when scanning for
the best pack to close.
diff add3a0a4da2f46f69a87782699e77c794a8b2cb9 uncommitted
--- a/sys/src/cmd/git/pack.c
+++ b/sys/src/cmd/git/pack.c
@@ -253,28 +253,44 @@
vlong t;
int i, best;
- if(pf->pack == nil){
- if((pf->pack = Bopen(pf->path, OREAD)) == nil)
- return nil;
- openpacks++;
+ if(pf->pack != nil){
+ pf->refs++;
+ return pf->pack;
}
- if(openpacks == Npackcache){
- t = pf->opentm;
+ /*
+ * If we've got more packs open
+ * than we want cached, try to
+ * free up the oldest ones.
+ *
+ * If we can't find a slot, this
+ * isn't fatal; we can just use
+ * another fd.
+ */
+ while(openpacks >= Npackcache){
+ t = (1ull<<62)-1;
best = -1;
for(i = 0; i < npackf; i++){
- if(packf[i].opentm < t && packf[i].refs > 0){
+ if(&packf[i] != pf
+ && packf[i].pack != nil
+ && packf[i].opentm < t
+ && packf[i].refs == 0){
t = packf[i].opentm;
best = i;
}
}
- if(best != -1){
- Bterm(packf[best].pack);
- packf[best].pack = nil;
- openpacks--;
+ if(best == -1){
+ fprint(2, "no available pack slots\n");
+ break;
}
+ Bterm(packf[best].pack);
+ packf[best].pack = nil;
+ openpacks--;
}
+ openpacks++;
pf->opentm = nsec();
pf->refs++;
+ if((pf->pack = Bopen(pf->path, OREAD)) == nil)
+ return nil;
return pf->pack;
}
@@ -281,10 +297,7 @@
static void
closepack(Packf *pf)
{
- if(--pf->refs == 0 && pf->pack != nil){
- Bterm(pf->pack);
- pf->pack = nil;
- }
+ pf->refs--;
}
static u32int
reply other threads:[~2021-11-26 5:52 UTC|newest]
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