[PATCH 5/6] XFS: remove congestion_wait() loop from kmem_alloc()

NeilBrown
2021-09-14T00:28:37Z

Documentation commment in gfp.h discourages indefinite retry loops on
ENOMEM and says of __GFP_NOFAIL that it

is definitely preferable to use the flag rather than opencode
endless loop around allocator.

So remove the loop, instead specifying __GFP_NOFAIL if KM_MAYFAIL was
not given.

Signed-off-by: NeilBrown <neilb@suse.de>
---
fs/xfs/kmem.c | 16 ++++------------
1 file changed, 4 insertions(+), 12 deletions(-)

diff --git a/fs/xfs/kmem.c b/fs/xfs/kmem.c
index 6f49bf39183c..f545f3633f88 100644
--- a/fs/xfs/kmem.c
+++ b/fs/xfs/kmem.c
@@ -13,19 +13,11 @@ kmem_alloc(size_t size, xfs_km_flags_t flags)
{
int retries = 0;
gfp_t lflags = kmem_flags_convert(flags);
- void *ptr;

trace_kmem_alloc(size, flags, _RET_IP_);

- do {
- ptr = kmalloc(size, lflags);
- if (ptr || (flags & KM_MAYFAIL))
- return ptr;
- if (!(++retries % 100))
- xfs_err(NULL,
- "%s(%u) possible memory allocation deadlock size %u in %s (mode:0x%x)",
- current->comm, current->pid,
- (unsigned int)size, __func__, lflags);
- congestion_wait(BLK_RW_ASYNC, HZ/50);
- } while (1);
+ if (!(flags & KM_MAYFAIL))
+ lflags |= __GFP_NOFAIL;
+
+ return kmalloc(size, lflags);
}