2019-12-10 20:30:50

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH 6/6] nfsd: Reduce the number of calls to nfsd_file_gc()

Don't call nfsd_file_gc() on every put of the reference in nfsd_file_put().
Instead, do it only when we're expecting the refcount to go to 1.

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfsd/filecache.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index 4cef03a7726c..9c2b29e07975 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -282,27 +282,32 @@ nfsd_file_unhash_and_release_locked(struct nfsd_file *nf, struct list_head *disp
return true;
}

-static int
+static void
nfsd_file_put_noref(struct nfsd_file *nf)
{
- int count;
trace_nfsd_file_put(nf);

- count = atomic_dec_return(&nf->nf_ref);
- if (!count) {
+ if (atomic_dec_and_test(&nf->nf_ref)) {
WARN_ON(test_bit(NFSD_FILE_HASHED, &nf->nf_flags));
nfsd_file_free(nf);
}
- return count;
}

void
nfsd_file_put(struct nfsd_file *nf)
{
- bool is_hashed = test_bit(NFSD_FILE_HASHED, &nf->nf_flags) != 0;
+ bool is_hashed;

set_bit(NFSD_FILE_REFERENCED, &nf->nf_flags);
- if (nfsd_file_put_noref(nf) == 1 && is_hashed)
+ if (atomic_read(&nf->nf_ref) > 2 || !nf->nf_file) {
+ nfsd_file_put_noref(nf);
+ return;
+ }
+
+ filemap_flush(nf->nf_file->f_mapping);
+ is_hashed = test_bit(NFSD_FILE_HASHED, &nf->nf_flags) != 0;
+ nfsd_file_put_noref(nf);
+ if (is_hashed)
nfsd_file_schedule_laundrette();
if (atomic_long_read(&nfsd_filecache_count) >= NFSD_FILE_LRU_LIMIT)
nfsd_file_gc();
--
2.23.0