code: mafs

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streamlined memory allocation global variables

--- a/all.h

+++ b/all.h

@@ -15,7 +15,6 @@

 	/*

 	https://cs.stackexchange.com/questions/11029/why-is-it-best-to-use-a-prime-number-as-a-mod-in-a-hashing-function

 		using small numbers for testing

-		using Nbuckets=2 for testing.

 	Size of buffer cache is approximately (Nbuckets * Ncollisions * Rawblocksize).

@@ -23,10 +22,7 @@

 	Ncollisions as the hash index lookup is faster than searching

 	through a linked list.

 	 */

-	Nbuckets = 256*KiB,	/* number of Hiob, hash buckets */

-	Ncollisions = 4,	/* soft limit after which we start reusing older Iobuf's */

-	Npendingwrites	= MiB,	/* write throttling */

-	Nmemunits = 8*MiB,	/* total memunit usage */

+	Ncollisions = 3,	/* soft limit after which we start reusing older Iobuf's */

 };

 typedef	struct	Hiob	Hiob;

@@ -84,7 +80,7 @@

 	u8 tofree;		/* free this Iobuf after the dirty blocks are written to the disk */

 };

-extern	u32	nbuckets;		/* n hash buckets for i/o */

+extern	u64	nbuckets;		/* n hash buckets for i/o */

 extern	Extents frees;		/* extents of free blocks on the disk */

 #include "fns.h"

@@ -113,7 +109,7 @@

 void	freeblockbuf(Iobuf *buf);

 void	freeblock(u64 blkno, u16 tag, u64 qpath);

 void	fsok(int ok);

-void	init(int doream);

+void	init(int doream, u64 size);

 u64		newqpath();

 u64		nperiblock(u16 tag);

 void	ream(u64 size);

--- a/free.c

+++ b/free.c

@@ -50,6 +50,7 @@

 		print("%s %llud bytes %llud blocks\n", devfile, size, size/Rawblocksize);

 	checkblock(Bdfrees, Tdentry, Qpfrees);

+	initextents(&frees);

 	getfrees(Bdfrees);

 // showextents("after getfrees", &frees);

 	showblocknos(1, &frees);

--- a/iobuf.c

+++ b/iobuf.c

@@ -1,6 +1,6 @@

 #include "all.h"

-u32  nbuckets = 0;	/* nbuckets derived from -m or Nbuckets */

+u64  nbuckets = 0;	/* number of hash buckets, -m changes it */

 Hiob *hiob = nil;	/* array of nbuckets */

 Extents frees = {0};/* extents of free blocks on the disk */

@@ -17,6 +17,10 @@

 {

 	memunitpool = sbrk(nunits * Rawblocksize);

 	initextents(&memunits);

+	if(chatty9p > 4)

+		dprint("initmemunitpool: memunitpool %p nunits*Rawblocksize %p\n",

+				memunitpool, nunits*Rawblocksize);

+	bfree(&memunits, (u64)memunitpool, nunits*Rawblocksize);

 }

 u8 *

@@ -24,11 +28,14 @@

 {

 	u64 m;

-	m = balloc(&memunits, 1);

+	m = balloc(&memunits, Rawblocksize);

 	if(m == 0)

 		panic("allocmemunit: no memory available");

-	return memunitpool+m;

+	if(chatty9p > 4)

+		dprint("allocmemunit: memunitpool %p m %p\n",

+				memunitpool, m);

+	return (u8*)m;

 }

 void

@@ -36,7 +43,7 @@

 {

 	if(m == 0)

 		panic("freememunit: m == 0\n");

-	bfree(&memunits, m-memunitpool, 1);

+	bfree(&memunits, (u64)m, Rawblocksize);

 }

@@ -88,7 +95,7 @@

 {

 	Hiob *hp;

 	Iobuf *s, *p;

-	s8 ncollisions;

+	u64 ncollisions;

 	hp = &hiob[blkno%nbuckets];

--- a/mafs.c

+++ b/mafs.c

@@ -44,7 +44,7 @@

 	int doream, stdio, netc;

 	char buf[Namelen];

 	int pid, ctl;

-	u64 nmemunits;

+	u64 nmemunits, size;

 	progname = "mafs";

 	procname = "init";

@@ -56,9 +56,9 @@

 	 */

 	rfork(RFNAMEG|RFNOTEG|RFREND);

-	nbuckets = Nbuckets;

-	npendingwrites = Npendingwrites;

-	nmemunits = Nmemunits;

+	nbuckets = 0;

+	npendingwrites = 0;

+	nmemunits = 0;

 	sfd = -1;

 	doream = stdio = netc = 0;

@@ -98,22 +98,37 @@

 	if(devfile == nil)

 		sysfatal("no disk file");

+	if (access(devfile, AREAD|AWRITE) == -1)

+		sysfatal("%s cannot access device", devfile);

+

+	size = devinit(devfile);

+	if(size == 0)

+		panic("null size %s", devfile);

+

+	/* 2/3rds of the memory for the pending writes

+		and 1/3rd for the buffer cache */

+	if(nmemunits == 0)

+		nmemunits = size/Rawblocksize > 8*MiB ? 8*MiB : size/Rawblocksize;

+	if(nmemunits < KiB)

+		nmemunits = KiB;

+	if(npendingwrites == 0)

+		npendingwrites = 2*nmemunits/3;

+	if(nbuckets == 0)

+		nbuckets = nmemunits/(3*Ncollisions);

+

 	if(chatty9p){

 		dprint("\nPlan 9 %d-bit file server with %d-deep indirect blocks\n",

 			sizeof(u64)*8, Niblock);

 		printsizes();

+		dprint("nmemunits %llud npendingwrites %llud nbuckets %llud\n",

+				nmemunits, npendingwrites, nbuckets);

 	}

-	if (access(devfile, AREAD|AWRITE) == -1)

-		sysfatal("%s cannot access device", devfile);

-

-	if(npendingwrites == 0)

-		npendingwrites = KiB;

-

 	formatinit();

 	initmemunitpool(nmemunits);

 	initextents(&frees);

+

 	tlocks = emalloc9p(NTLOCK * sizeof *tlocks);

 	initwriter();

 	iobufinit();

@@ -122,7 +137,7 @@

 	 * init the file system, ream it if needed, and get the block sizes.

 	 * service = config.service, if service is nil.

 	 */

-	init(doream);

+	init(doream, size);

 	if(service[0] == '\0')

 		snprint(service, Namelen, "%s", config.service);

--- a/reconcile.c

+++ b/reconcile.c

@@ -156,6 +156,7 @@

 	if(debug)

 		print("collect %s ", s->name);

 	s->es = emalloc(sizeof(Extents));

+	initextents(s->es);

 	while((s->buf = Brdstr(&s->bp, '\n', 1)) != nil) {

 		bno = atoll(s->buf);

 		add(s->es, bno, 1);

--- a/sub.c

+++ b/sub.c

@@ -480,17 +480,12 @@

 }

 void

-init(int doream)

+init(int doream, u64 size)

 {

 	u32 rbufsize;

-	u64 size;

 	Iobuf *sb, *b;

 	Superb *s;

 	s8 *rptr;

-

-	size = devinit(devfile);

-	if(size == 0)

-		panic("null size %s", devfile);

 	if(doream)

 		ream(size);

--- a/writer.c

+++ b/writer.c

@@ -119,7 +119,7 @@

 	w = emalloc9p(sizeof(Wbuf));

 	w->blkno = b->blkno;

 	w->payload = allocmemunit();

-	memcpy(w->io, b->io, Rawblocksize);

+	memcpy(w->payload, b->xiobuf, Rawblocksize);

 	if(drts.head == nil){

 		drts.head = drts.tail = w;

 	}else{