NFS: nfsiod should not block forever in mempool_alloc()

The concern is that since nfsiod is sometimes required to kick off a
commit, it can get locked up waiting forever in mempool_alloc() instead
of failing gracefully and leaving the commit until later.

Try to allocate from the slab first, with GFP_KERNEL | __GFP_NORETRY,
then fall back to a non-blocking attempt to allocate from the memory
pool.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Trond Myklebust 2022-03-21 12:34:19 -04:00
parent b2648015d4
commit 515dcdcd48
4 changed files with 23 additions and 18 deletions

View File

@ -587,6 +587,13 @@ nfs_write_match_verf(const struct nfs_writeverf *verf,
!nfs_write_verifier_cmp(&req->wb_verf, &verf->verifier);
}
static inline gfp_t nfs_io_gfp_mask(void)
{
if (current->flags & PF_WQ_WORKER)
return GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN;
return GFP_KERNEL;
}
/* unlink.c */
extern struct rpc_task *
nfs_async_rename(struct inode *old_dir, struct inode *new_dir,

View File

@ -419,7 +419,7 @@ static struct nfs_commit_data *
pnfs_bucket_fetch_commitdata(struct pnfs_commit_bucket *bucket,
struct nfs_commit_info *cinfo)
{
struct nfs_commit_data *data = nfs_commitdata_alloc(false);
struct nfs_commit_data *data = nfs_commitdata_alloc();
if (!data)
return NULL;
@ -515,7 +515,11 @@ pnfs_generic_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
unsigned int nreq = 0;
if (!list_empty(mds_pages)) {
data = nfs_commitdata_alloc(true);
data = nfs_commitdata_alloc();
if (!data) {
nfs_retry_commit(mds_pages, NULL, cinfo, -1);
return -ENOMEM;
}
data->ds_commit_index = -1;
list_splice_init(mds_pages, &data->pages);
list_add_tail(&data->list, &list);

View File

@ -70,27 +70,17 @@ static mempool_t *nfs_wdata_mempool;
static struct kmem_cache *nfs_cdata_cachep;
static mempool_t *nfs_commit_mempool;
struct nfs_commit_data *nfs_commitdata_alloc(bool never_fail)
struct nfs_commit_data *nfs_commitdata_alloc(void)
{
struct nfs_commit_data *p;
if (never_fail)
p = mempool_alloc(nfs_commit_mempool, GFP_NOIO);
else {
/* It is OK to do some reclaim, not no safe to wait
* for anything to be returned to the pool.
* mempool_alloc() cannot handle that particular combination,
* so we need two separate attempts.
*/
p = kmem_cache_zalloc(nfs_cdata_cachep, nfs_io_gfp_mask());
if (!p) {
p = mempool_alloc(nfs_commit_mempool, GFP_NOWAIT);
if (!p)
p = kmem_cache_alloc(nfs_cdata_cachep, GFP_NOIO |
__GFP_NOWARN | __GFP_NORETRY);
if (!p)
return NULL;
memset(p, 0, sizeof(*p));
}
memset(p, 0, sizeof(*p));
INIT_LIST_HEAD(&p->pages);
return p;
}
@ -1826,7 +1816,11 @@ nfs_commit_list(struct inode *inode, struct list_head *head, int how,
if (list_empty(head))
return 0;
data = nfs_commitdata_alloc(true);
data = nfs_commitdata_alloc();
if (!data) {
nfs_retry_commit(head, NULL, cinfo, -1);
return -ENOMEM;
}
/* Set up the argument struct */
nfs_init_commit(data, head, NULL, cinfo);

View File

@ -580,7 +580,7 @@ extern int nfs_wb_all(struct inode *inode);
extern int nfs_wb_page(struct inode *inode, struct page *page);
extern int nfs_wb_page_cancel(struct inode *inode, struct page* page);
extern int nfs_commit_inode(struct inode *, int);
extern struct nfs_commit_data *nfs_commitdata_alloc(bool never_fail);
extern struct nfs_commit_data *nfs_commitdata_alloc(void);
extern void nfs_commit_free(struct nfs_commit_data *data);
bool nfs_commit_end(struct nfs_mds_commit_info *cinfo);