From: Greg Banks Date: Mon, 2 Oct 2006 09:18:02 +0000 (-0700) Subject: [PATCH] knfsd: allow admin to set nthreads per node X-Git-Tag: v2.6.19-rc1~422 X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=commitdiff_plain;h=eed2965af1bae30f746e936d80ad4fabb9e208c8 [PATCH] knfsd: allow admin to set nthreads per node Add /proc/fs/nfsd/pool_threads which allows the sysadmin (or a userspace daemon) to read and change the number of nfsd threads in each pool. The format is a list of space-separated integers, one per pool. Signed-off-by: Greg Banks Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index 36e8e13..5c6a477 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -54,6 +54,7 @@ enum { NFSD_List, NFSD_Fh, NFSD_Threads, + NFSD_Pool_Threads, NFSD_Versions, NFSD_Ports, /* @@ -78,6 +79,7 @@ static ssize_t write_getfd(struct file *file, char *buf, size_t size); static ssize_t write_getfs(struct file *file, char *buf, size_t size); static ssize_t write_filehandle(struct file *file, char *buf, size_t size); static ssize_t write_threads(struct file *file, char *buf, size_t size); +static ssize_t write_pool_threads(struct file *file, char *buf, size_t size); static ssize_t write_versions(struct file *file, char *buf, size_t size); static ssize_t write_ports(struct file *file, char *buf, size_t size); #ifdef CONFIG_NFSD_V4 @@ -95,6 +97,7 @@ static ssize_t (*write_op[])(struct file *, char *, size_t) = { [NFSD_Getfs] = write_getfs, [NFSD_Fh] = write_filehandle, [NFSD_Threads] = write_threads, + [NFSD_Pool_Threads] = write_pool_threads, [NFSD_Versions] = write_versions, [NFSD_Ports] = write_ports, #ifdef CONFIG_NFSD_V4 @@ -363,6 +366,72 @@ static ssize_t write_threads(struct file *file, char *buf, size_t size) return strlen(buf); } +extern int nfsd_nrpools(void); +extern int nfsd_get_nrthreads(int n, int *); +extern int nfsd_set_nrthreads(int n, int *); + +static ssize_t write_pool_threads(struct file *file, char *buf, size_t size) +{ + /* if size > 0, look for an array of number of threads per node + * and apply them then write out number of threads per node as reply + */ + char *mesg = buf; + int i; + int rv; + int len; + int npools = nfsd_nrpools(); + int *nthreads; + + if (npools == 0) { + /* + * NFS is shut down. The admin can start it by + * writing to the threads file but NOT the pool_threads + * file, sorry. Report zero threads. + */ + strcpy(buf, "0\n"); + return strlen(buf); + } + + nthreads = kcalloc(npools, sizeof(int), GFP_KERNEL); + if (nthreads == NULL) + return -ENOMEM; + + if (size > 0) { + for (i = 0; i < npools; i++) { + rv = get_int(&mesg, &nthreads[i]); + if (rv == -ENOENT) + break; /* fewer numbers than pools */ + if (rv) + goto out_free; /* syntax error */ + rv = -EINVAL; + if (nthreads[i] < 0) + goto out_free; + } + rv = nfsd_set_nrthreads(i, nthreads); + if (rv) + goto out_free; + } + + rv = nfsd_get_nrthreads(npools, nthreads); + if (rv) + goto out_free; + + mesg = buf; + size = SIMPLE_TRANSACTION_LIMIT; + for (i = 0; i < npools && size > 0; i++) { + snprintf(mesg, size, "%d%c", nthreads[i], (i == npools-1 ? '\n' : ' ')); + len = strlen(mesg); + size -= len; + mesg += len; + } + + return (mesg-buf); + +out_free: + kfree(nthreads); + return rv; +} + static ssize_t write_versions(struct file *file, char *buf, size_t size) { /* @@ -544,6 +613,7 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent) [NFSD_List] = {"exports", &exports_operations, S_IRUGO}, [NFSD_Fh] = {"filehandle", &transaction_ops, S_IWUSR|S_IRUSR}, [NFSD_Threads] = {"threads", &transaction_ops, S_IWUSR|S_IRUSR}, + [NFSD_Pool_Threads] = {"pool_threads", &transaction_ops, S_IWUSR|S_IRUSR}, [NFSD_Versions] = {"versions", &transaction_ops, S_IWUSR|S_IRUSR}, [NFSD_Ports] = {"portlist", &transaction_ops, S_IWUSR|S_IRUGO}, #ifdef CONFIG_NFSD_V4 diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c index 0029cb2..1944305 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -238,6 +238,80 @@ static int nfsd_init_socks(int port) return 0; } +int nfsd_nrpools(void) +{ + if (nfsd_serv == NULL) + return 0; + else + return nfsd_serv->sv_nrpools; +} + +int nfsd_get_nrthreads(int n, int *nthreads) +{ + int i = 0; + + if (nfsd_serv != NULL) { + for (i = 0; i < nfsd_serv->sv_nrpools && i < n; i++) + nthreads[i] = nfsd_serv->sv_pools[i].sp_nrthreads; + } + + return 0; +} + +int nfsd_set_nrthreads(int n, int *nthreads) +{ + int i = 0; + int tot = 0; + int err = 0; + + if (nfsd_serv == NULL || n <= 0) + return 0; + + if (n > nfsd_serv->sv_nrpools) + n = nfsd_serv->sv_nrpools; + + /* enforce a global maximum number of threads */ + tot = 0; + for (i = 0; i < n; i++) { + if (nthreads[i] > NFSD_MAXSERVS) + nthreads[i] = NFSD_MAXSERVS; + tot += nthreads[i]; + } + if (tot > NFSD_MAXSERVS) { + /* total too large: scale down requested numbers */ + for (i = 0; i < n && tot > 0; i++) { + int new = nthreads[i] * NFSD_MAXSERVS / tot; + tot -= (nthreads[i] - new); + nthreads[i] = new; + } + for (i = 0; i < n && tot > 0; i++) { + nthreads[i]--; + tot--; + } + } + + /* + * There must always be a thread in pool 0; the admin + * can't shut down NFS completely using pool_threads. + */ + if (nthreads[0] == 0) + nthreads[0] = 1; + + /* apply the new numbers */ + lock_kernel(); + svc_get(nfsd_serv); + for (i = 0; i < n; i++) { + err = svc_set_num_threads(nfsd_serv, &nfsd_serv->sv_pools[i], + nthreads[i]); + if (err) + break; + } + svc_destroy(nfsd_serv); + unlock_kernel(); + + return err; +} + int nfsd_svc(unsigned short port, int nrservs) {