xnu-344.tar.gz

[apple/xnu.git] / bsd / nfs / nfs_bio.c

diff --git a/bsd/nfs/nfs_bio.c b/bsd/nfs/nfs_bio.c
index 3c4473b4447f85a5944ba06431825fb890a29b38..7a7394c7869f4d6be5396dcf550d21c4dae5ecbe 100644 (file)
--- a/bsd/nfs/nfs_bio.c
+++ b/bsd/nfs/nfs_bio.c
@@ -100,6 +100,7 @@ static struct buf *nfs_getcacheblk __P((struct vnode *vp, daddr_t bn, int size,
 
 extern int nfs_numasync;
 extern struct nfsstats nfsstats;
+extern int nbdwrite;
 
 /*
  * Vnode op for read using bio
@@ -848,6 +849,22 @@ nfs_getcacheblk(vp, bn, size, p, operation)
        /*due to getblk/vm interractions, use vm page size or less values */
        int biosize = min(vp->v_mount->mnt_stat.f_iosize, PAGE_SIZE);
 
+       if (nbdwrite > ((nbuf/4)*3) && operation == BLK_WRITE) {
+#define __BUFFERS_RECLAIMED 2
+               struct buf *tbp[__BUFFERS_RECLAIMED];
+               int i;
+
+               /* too many delayed writes, try to free up some buffers */
+               for (i = 0; i < __BUFFERS_RECLAIMED; i++)
+                       tbp[i] = geteblk(512);
+
+               /* Yield to IO thread */
+               (void)tsleep((caddr_t)&nbdwrite, PCATCH, "nbdwrite", 1);
+
+               for (i = (__BUFFERS_RECLAIMED - 1); i >= 0; i--)
+                        brelse(tbp[i]);
+       }
+
        if (nmp->nm_flag & NFSMNT_INT) {
                bp = getblk(vp, bn, size, PCATCH, 0, operation);
                while (bp == (struct buf *)0) {
@@ -1169,7 +1186,7 @@ nfs_doio(bp, cr, p)
                                bp->b_validend = diff;
                    } else
                                bp->b_validend = bp->b_bcount;
-#if 1 /* USV + JOE [ */
+
                    if (bp->b_validend < bp->b_bufsize) {
                            /*
                             * we're about to release a partial buffer after a
@@ -1185,7 +1202,6 @@ nfs_doio(bp, cr, p)
                            FSDBG(258, bp->b_validend,
                                  bp->b_bufsize - bp->b_validend, 0, 2);
                    }
-#endif /* ] USV + JOE */
                }
                if (p && (vp->v_flag & VTEXT) &&
                        (((nmp->nm_flag & NFSMNT_NQNFS) &&
@@ -1279,7 +1295,6 @@ nfs_doio(bp, cr, p)
 
                        CLR(bp->b_flags, B_INVAL | B_NOCACHE);
                        if (!ISSET(bp->b_flags, B_DELWRI)) {
-                               extern int nbdwrite;
                                SET(bp->b_flags, B_DELWRI);
                                nbdwrite++;
                        }
@@ -1304,7 +1319,7 @@ nfs_doio(bp, cr, p)
                                np->n_flag |= NWRITEERR;
                        }
                        bp->b_dirtyoff = bp->b_dirtyend = 0;
-#if 1  /* JOE */
+
                        /*
                         * validoff and validend represent the real data present
                         * in this buffer if validoff is non-zero, than we have
@@ -1331,11 +1346,9 @@ nfs_doio(bp, cr, p)
                                } else
                                        SET(bp->b_flags, B_INVAL);
                        }
-#endif
                }
 
            } else {
-#if 1  /* JOE */
                if (bp->b_validoff ||
                    (bp->b_validend < bp->b_bufsize &&
                     (off_t)bp->b_blkno * DEV_BSIZE + bp->b_validend !=
@@ -1346,7 +1359,6 @@ nfs_doio(bp, cr, p)
                        FSDBG(260, bp->b_validoff, bp->b_validend,
                              bp->b_bufsize, bp->b_bcount);
                }
-#endif
                bp->b_resid = 0;
                biodone(bp);
                FSDBG_BOT(256, bp->b_validoff, bp->b_validend, bp->b_bufsize,