diff options
| -rw-r--r-- | fs/nfsd/nfs4state.c | 26 | ||||
| -rw-r--r-- | include/linux/nfsd/nfsd.h | 1 | ||||
| -rw-r--r-- | mm/page_alloc.c | 1 |
3 files changed, 27 insertions, 1 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 9cc31eaf3857..46249886ea86 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -49,6 +49,7 @@ #include <linux/nfsd/state.h> #include <linux/nfsd/xdr4.h> #include <linux/namei.h> +#include <linux/swap.h> #include <linux/mutex.h> #include <linux/lockd/bind.h> #include <linux/module.h> @@ -150,6 +151,7 @@ get_nfs4_file(struct nfs4_file *fi) } static int num_delegations; +unsigned int max_delegations; /* * Open owner state (share locks) @@ -193,7 +195,7 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_stateid *stp, struct svc_f struct nfs4_callback *cb = &stp->st_stateowner->so_client->cl_callback; dprintk("NFSD alloc_init_deleg\n"); - if (num_delegations > STATEID_HASH_SIZE * 4) + if (num_delegations > max_delegations) return NULL; dp = kmem_cache_alloc(deleg_slab, GFP_KERNEL); if (dp == NULL) @@ -3197,6 +3199,27 @@ get_nfs4_grace_period(void) return max(user_lease_time, lease_time) * HZ; } +/* + * Since the lifetime of a delegation isn't limited to that of an open, a + * client may quite reasonably hang on to a delegation as long as it has + * the inode cached. This becomes an obvious problem the first time a + * client's inode cache approaches the size of the server's total memory. + * + * For now we avoid this problem by imposing a hard limit on the number + * of delegations, which varies according to the server's memory size. + */ +static void +set_max_delegations(void) +{ + /* + * Allow at most 4 delegations per megabyte of RAM. Quick + * estimates suggest that in the worst case (where every delegation + * is for a different inode), a delegation could take about 1.5K, + * giving a worst case usage of about 6% of memory. + */ + max_delegations = nr_free_buffer_pages() >> (20 - 2 - PAGE_SHIFT); +} + /* initialization to perform when the nfsd service is started: */ static void @@ -3212,6 +3235,7 @@ __nfs4_state_start(void) grace_time/HZ); laundry_wq = create_singlethread_workqueue("nfsd4"); queue_delayed_work(laundry_wq, &laundromat_work, grace_time); + set_max_delegations(); } int diff --git a/include/linux/nfsd/nfsd.h b/include/linux/nfsd/nfsd.h index 0d8420497765..ce5e345a9bce 100644 --- a/include/linux/nfsd/nfsd.h +++ b/include/linux/nfsd/nfsd.h @@ -148,6 +148,7 @@ extern int nfsd_max_blksize; * NFSv4 State */ #ifdef CONFIG_NFSD_V4 +extern unsigned int max_delegations; void nfs4_state_init(void); int nfs4_state_start(void); void nfs4_state_shutdown(void); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 1a889c3fec59..e2a10b957f23 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1484,6 +1484,7 @@ unsigned int nr_free_buffer_pages(void) { return nr_free_zone_pages(gfp_zone(GFP_USER)); } +EXPORT_SYMBOL_GPL(nr_free_buffer_pages); /* * Amount of free RAM allocatable within all zones |