ref: deeb8ec05b7b0b9d493ee90258b22f4bc7f4aaa6
dir: /cache.c/
#include <u.h> #include <libc.h> #include <fcall.h> #include <avl.h> #include "dat.h" #include "fns.h" static void lrudel(Blk *b) { if(b == fs->chead) fs->chead = b->cnext; if(b == fs->ctail) fs->ctail = b->cprev; if(b->cnext != nil) b->cnext->cprev = b->cprev; if(b->cprev != nil) b->cprev->cnext = b->cnext; b->cnext = nil; b->cprev = nil; } void lrutop(Blk *b) { qlock(&fs->lrulk); /* * Someone got in first and did a * cache lookup; we no longer want * to put this into the LRU, because * its now in use. */ assert(b->magic == Magic); if(b->ref != 0){ qunlock(&fs->lrulk); return; } lrudel(b); if(fs->chead != nil) fs->chead->cprev = b; if(fs->ctail == nil) fs->ctail = b; b->cnext = fs->chead; fs->chead = b; rwakeup(&fs->lrurz); qunlock(&fs->lrulk); } void lrubot(Blk *b) { qlock(&fs->lrulk); /* * Someone got in first and did a * cache lookup; we no longer want * to put this into the LRU, because * its now in use. */ assert(b->magic == Magic); if(b->ref != 0){ qunlock(&fs->lrulk); return; } lrudel(b); if(fs->ctail != nil) fs->ctail->cnext = b; if(fs->chead == nil) fs->chead = b; b->cprev = fs->ctail; fs->ctail = b; rwakeup(&fs->lrurz); qunlock(&fs->lrulk); } void cacheins(Blk *b) { Bucket *bkt; u32int h; assert(b->magic == Magic); h = ihash(b->bp.addr); bkt = &fs->bcache[h % fs->cmax]; qlock(&fs->lrulk); lock(bkt); if(checkflag(b, Bcached)){ unlock(bkt); qunlock(&fs->lrulk); return; } assert(b->hnext == nil); for(Blk *bb = bkt->b; bb != nil; bb = bb->hnext) assert(b != bb); setflag(b, Bcached); b->cached = getcallerpc(&b); b->hnext = bkt->b; bkt->b = b; unlock(bkt); qunlock(&fs->lrulk); } void cachedel_lk(vlong addr) { Bucket *bkt; Blk *b, **p; u32int h; if(addr == -1) return; h = ihash(addr); bkt = &fs->bcache[h % fs->cmax]; lock(bkt); p = &bkt->b; for(b = bkt->b; b != nil; b = b->hnext){ if(b->bp.addr == addr){ *p = b->hnext; clrflag(b, Bcached); b->uncached = getcallerpc(&addr); b->hnext = nil; break; } p = &b->hnext; } unlock(bkt); } void cachedel(vlong addr) { qlock(&fs->lrulk); cachedel_lk(addr); qunlock(&fs->lrulk); } Blk* cacheget(vlong addr) { Bucket *bkt; u32int h; Blk *b; h = ihash(addr); bkt = &fs->bcache[h % fs->cmax]; qlock(&fs->lrulk); lock(bkt); for(b = bkt->b; b != nil; b = b->hnext){ if(b->bp.addr == addr){ holdblk(b); lrudel(b); b->lasthold = getcallerpc(&addr); break; } } unlock(bkt); qunlock(&fs->lrulk); return b; } /* * Pulls the block from the bottom of the LRU for reuse. */ Blk* cachepluck(void) { Blk *b; qlock(&fs->lrulk); while(fs->ctail == nil) rsleep(&fs->lrurz); b = fs->ctail; assert(b->magic == Magic); assert(b->ref == 0); if(checkflag(b, Bcached)) cachedel_lk(b->bp.addr); if(checkflag(b, Bcached)) print("%B cached %#p freed %#p\n", b->bp, b->cached, b->freed); lrudel(b); assert(!checkflag(b, Bcached)); b->flag = 0; b->lasthold = 0; b->lastdrop = 0; b->freed = 0; b->hnext = nil; qunlock(&fs->lrulk); return holdblk(b); }