From 501cb1849f865960501d19d54e6a5af306f9b6fd Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Sun, 18 Aug 2019 14:18:56 -0400 Subject: nfsd: rip out the raparms cache The raparms cache was set up in order to ensure that we carry readahead information forward from one RPC call to the next. In other words, it was set up because each RPC call was forced to open a struct file, then close it, causing the loss of readahead information that is normally cached in that struct file, and used to keep the page cache filled when a user calls read() multiple times on the same file descriptor. Now that we cache the struct file, and reuse it for all the I/O calls to a given file by a given user, we no longer have to keep a separate readahead cache. Signed-off-by: Jeff Layton Signed-off-by: Trond Myklebust Signed-off-by: Trond Myklebust Signed-off-by: J. Bruce Fields --- fs/nfsd/vfs.c | 149 ---------------------------------------------------------- 1 file changed, 149 deletions(-) (limited to 'fs/nfsd/vfs.c') diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index ec254bff1893..8e2c8f36eba3 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -49,34 +49,6 @@ #define NFSDDBG_FACILITY NFSDDBG_FILEOP - -/* - * This is a cache of readahead params that help us choose the proper - * readahead strategy. Initially, we set all readahead parameters to 0 - * and let the VFS handle things. - * If you increase the number of cached files very much, you'll need to - * add a hash table here. - */ -struct raparms { - struct raparms *p_next; - unsigned int p_count; - ino_t p_ino; - dev_t p_dev; - int p_set; - struct file_ra_state p_ra; - unsigned int p_hindex; -}; - -struct raparm_hbucket { - struct raparms *pb_head; - spinlock_t pb_lock; -} ____cacheline_aligned_in_smp; - -#define RAPARM_HASH_BITS 4 -#define RAPARM_HASH_SIZE (1<i_sb->s_dev; - ino_t ino = inode->i_ino; - struct raparms *ra, **rap, **frap = NULL; - int depth = 0; - unsigned int hash; - struct raparm_hbucket *rab; - - hash = jhash_2words(dev, ino, 0xfeedbeef) & RAPARM_HASH_MASK; - rab = &raparm_hash[hash]; - - spin_lock(&rab->pb_lock); - for (rap = &rab->pb_head; (ra = *rap); rap = &ra->p_next) { - if (ra->p_ino == ino && ra->p_dev == dev) - goto found; - depth++; - if (ra->p_count == 0) - frap = rap; - } - depth = nfsdstats.ra_size; - if (!frap) { - spin_unlock(&rab->pb_lock); - return NULL; - } - rap = frap; - ra = *frap; - ra->p_dev = dev; - ra->p_ino = ino; - ra->p_set = 0; - ra->p_hindex = hash; -found: - if (rap != &rab->pb_head) { - *rap = ra->p_next; - ra->p_next = rab->pb_head; - rab->pb_head = ra; - } - ra->p_count++; - nfsdstats.ra_depth[depth*10/nfsdstats.ra_size]++; - spin_unlock(&rab->pb_lock); - - if (ra->p_set) - file->f_ra = ra->p_ra; - return ra; -} - -void nfsd_put_raparams(struct file *file, struct raparms *ra) -{ - struct raparm_hbucket *rab = &raparm_hash[ra->p_hindex]; - - spin_lock(&rab->pb_lock); - ra->p_ra = file->f_ra; - ra->p_set = 1; - ra->p_count--; - spin_unlock(&rab->pb_lock); -} - /* * Grab and keep cached pages associated with a file in the svc_rqst * so that they can be passed to the network sendmsg/sendpage routines @@ -2094,63 +2005,3 @@ nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp, return err? nfserrno(err) : 0; } - -void -nfsd_racache_shutdown(void) -{ - struct raparms *raparm, *last_raparm; - unsigned int i; - - dprintk("nfsd: freeing readahead buffers.\n"); - - for (i = 0; i < RAPARM_HASH_SIZE; i++) { - raparm = raparm_hash[i].pb_head; - while(raparm) { - last_raparm = raparm; - raparm = raparm->p_next; - kfree(last_raparm); - } - raparm_hash[i].pb_head = NULL; - } -} -/* - * Initialize readahead param cache - */ -int -nfsd_racache_init(int cache_size) -{ - int i; - int j = 0; - int nperbucket; - struct raparms **raparm = NULL; - - - if (raparm_hash[0].pb_head) - return 0; - nperbucket = DIV_ROUND_UP(cache_size, RAPARM_HASH_SIZE); - nperbucket = max(2, nperbucket); - cache_size = nperbucket * RAPARM_HASH_SIZE; - - dprintk("nfsd: allocating %d readahead buffers.\n", cache_size); - - for (i = 0; i < RAPARM_HASH_SIZE; i++) { - spin_lock_init(&raparm_hash[i].pb_lock); - - raparm = &raparm_hash[i].pb_head; - for (j = 0; j < nperbucket; j++) { - *raparm = kzalloc(sizeof(struct raparms), GFP_KERNEL); - if (!*raparm) - goto out_nomem; - raparm = &(*raparm)->p_next; - } - *raparm = NULL; - } - - nfsdstats.ra_size = cache_size; - return 0; - -out_nomem: - dprintk("nfsd: kmalloc failed, freeing readahead buffers\n"); - nfsd_racache_shutdown(); - return -ENOMEM; -} -- cgit v1.2.3-70-g09d2