2022-03-22 02:21:45

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH v2 6/9] NFS: Avoid writeback threads getting stuck in mempool_alloc()

From: Trond Myklebust <[email protected]>

In a low memory situation, allow the NFS writeback code to fail without
getting stuck in infinite loops in mempool_alloc().

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/pagelist.c | 10 +++++-----
fs/nfs/write.c | 10 ++++++++--
2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index ad7f83dc9a2d..3156db526cc4 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -90,10 +90,10 @@ void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos)
}
}

-static inline struct nfs_page *
-nfs_page_alloc(void)
+static inline struct nfs_page *nfs_page_alloc(void)
{
- struct nfs_page *p = kmem_cache_zalloc(nfs_page_cachep, GFP_KERNEL);
+ struct nfs_page *p =
+ kmem_cache_zalloc(nfs_page_cachep, nfs_io_gfp_mask());
if (p)
INIT_LIST_HEAD(&p->wb_list);
return p;
@@ -892,7 +892,7 @@ int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
struct nfs_commit_info cinfo;
struct nfs_page_array *pg_array = &hdr->page_array;
unsigned int pagecount, pageused;
- gfp_t gfp_flags = GFP_KERNEL;
+ gfp_t gfp_flags = nfs_io_gfp_mask();

pagecount = nfs_page_array_len(mirror->pg_base, mirror->pg_count);
pg_array->npages = pagecount;
@@ -979,7 +979,7 @@ nfs_pageio_alloc_mirrors(struct nfs_pageio_descriptor *desc,
desc->pg_mirrors_dynamic = NULL;
if (mirror_count == 1)
return desc->pg_mirrors_static;
- ret = kmalloc_array(mirror_count, sizeof(*ret), GFP_KERNEL);
+ ret = kmalloc_array(mirror_count, sizeof(*ret), nfs_io_gfp_mask());
if (ret != NULL) {
for (i = 0; i < mirror_count; i++)
nfs_pageio_mirror_init(&ret[i], desc->pg_bsize);
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index ef47e3700e4b..e864ac836237 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -94,9 +94,15 @@ EXPORT_SYMBOL_GPL(nfs_commit_free);

static struct nfs_pgio_header *nfs_writehdr_alloc(void)
{
- struct nfs_pgio_header *p = mempool_alloc(nfs_wdata_mempool, GFP_KERNEL);
+ struct nfs_pgio_header *p;

- memset(p, 0, sizeof(*p));
+ p = kmem_cache_zalloc(nfs_wdata_cachep, nfs_io_gfp_mask());
+ if (!p) {
+ p = mempool_alloc(nfs_wdata_mempool, GFP_NOWAIT);
+ if (!p)
+ return NULL;
+ memset(p, 0, sizeof(*p));
+ }
p->rw_mode = FMODE_WRITE;
return p;
}
--
2.35.1


2022-03-22 02:21:48

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH v2 7/9] NFSv4/pnfs: Ensure pNFS allocation modes are consistent with nfsiod

From: Trond Myklebust <[email protected]>

Ensure that pNFS allocations that can be called from rpciod/nfsiod
callback can fail in low memory mode, so that the threads don't block
and loop forever.

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/nfs42proc.c | 2 +-
fs/nfs/pnfs.c | 39 +++++++++++++++++----------------------
2 files changed, 18 insertions(+), 23 deletions(-)

diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c
index 882bf84484ac..b841e267b764 100644
--- a/fs/nfs/nfs42proc.c
+++ b/fs/nfs/nfs42proc.c
@@ -1017,7 +1017,7 @@ int nfs42_proc_layouterror(struct pnfs_layout_segment *lseg,
return -EOPNOTSUPP;
if (n > NFS42_LAYOUTERROR_MAX)
return -EINVAL;
- data = nfs42_alloc_layouterror_data(lseg, GFP_KERNEL);
+ data = nfs42_alloc_layouterror_data(lseg, nfs_io_gfp_mask());
if (!data)
return -ENOMEM;
for (i = 0; i < n; i++) {
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index f089e11fd001..de318bb5d349 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1233,7 +1233,7 @@ pnfs_send_layoutreturn(struct pnfs_layout_hdr *lo,
int status = 0;

*pcred = NULL;
- lrp = kzalloc(sizeof(*lrp), GFP_KERNEL);
+ lrp = kzalloc(sizeof(*lrp), nfs_io_gfp_mask());
if (unlikely(lrp == NULL)) {
status = -ENOMEM;
spin_lock(&ino->i_lock);
@@ -2206,7 +2206,7 @@ _pnfs_grab_empty_layout(struct inode *ino, struct nfs_open_context *ctx)
struct pnfs_layout_hdr *lo;

spin_lock(&ino->i_lock);
- lo = pnfs_find_alloc_layout(ino, ctx, GFP_KERNEL);
+ lo = pnfs_find_alloc_layout(ino, ctx, nfs_io_gfp_mask());
if (!lo)
goto out_unlock;
if (!test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags))
@@ -2249,8 +2249,8 @@ static void _lgopen_prepare_attached(struct nfs4_opendata *data,
lo = _pnfs_grab_empty_layout(ino, ctx);
if (!lo)
return;
- lgp = pnfs_alloc_init_layoutget_args(ino, ctx, &current_stateid,
- &rng, GFP_KERNEL);
+ lgp = pnfs_alloc_init_layoutget_args(ino, ctx, &current_stateid, &rng,
+ nfs_io_gfp_mask());
if (!lgp) {
pnfs_clear_first_layoutget(lo);
nfs_layoutget_end(lo);
@@ -2275,8 +2275,8 @@ static void _lgopen_prepare_floating(struct nfs4_opendata *data,
};
struct nfs4_layoutget *lgp;

- lgp = pnfs_alloc_init_layoutget_args(ino, ctx, &current_stateid,
- &rng, GFP_KERNEL);
+ lgp = pnfs_alloc_init_layoutget_args(ino, ctx, &current_stateid, &rng,
+ nfs_io_gfp_mask());
if (!lgp)
return;
data->lgp = lgp;
@@ -2691,13 +2691,11 @@ pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *r
else
rd_size = nfs_dreq_bytes_left(pgio->pg_dreq);

- pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
- nfs_req_openctx(req),
- req_offset(req),
- rd_size,
- IOMODE_READ,
- false,
- GFP_KERNEL);
+ pgio->pg_lseg =
+ pnfs_update_layout(pgio->pg_inode, nfs_req_openctx(req),
+ req_offset(req), rd_size,
+ IOMODE_READ, false,
+ nfs_io_gfp_mask());
if (IS_ERR(pgio->pg_lseg)) {
pgio->pg_error = PTR_ERR(pgio->pg_lseg);
pgio->pg_lseg = NULL;
@@ -2718,13 +2716,10 @@ pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio,
pnfs_generic_pg_check_layout(pgio);
pnfs_generic_pg_check_range(pgio, req);
if (pgio->pg_lseg == NULL) {
- pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
- nfs_req_openctx(req),
- req_offset(req),
- wb_size,
- IOMODE_RW,
- false,
- GFP_KERNEL);
+ pgio->pg_lseg =
+ pnfs_update_layout(pgio->pg_inode, nfs_req_openctx(req),
+ req_offset(req), wb_size, IOMODE_RW,
+ false, nfs_io_gfp_mask());
if (IS_ERR(pgio->pg_lseg)) {
pgio->pg_error = PTR_ERR(pgio->pg_lseg);
pgio->pg_lseg = NULL;
@@ -3183,7 +3178,7 @@ pnfs_layoutcommit_inode(struct inode *inode, bool sync)

status = -ENOMEM;
/* Note kzalloc ensures data->res.seq_res.sr_slot == NULL */
- data = kzalloc(sizeof(*data), GFP_NOFS);
+ data = kzalloc(sizeof(*data), nfs_io_gfp_mask());
if (!data)
goto clear_layoutcommitting;

@@ -3250,7 +3245,7 @@ struct nfs4_threshold *pnfs_mdsthreshold_alloc(void)
{
struct nfs4_threshold *thp;

- thp = kzalloc(sizeof(*thp), GFP_KERNEL);
+ thp = kzalloc(sizeof(*thp), nfs_io_gfp_mask());
if (!thp) {
dprintk("%s mdsthreshold allocation failed\n", __func__);
return NULL;
--
2.35.1