On Sun, Jul 27, 2025 at 12:16:04PM -0400, Chuck Lever wrote: > From: Chuck Lever <chuck.lever@xxxxxxxxxx> > > On Thu, 24 Jul 2025 15:30:49 -0400, Mike Snitzer wrote: > > Some workloads benefit from NFSD avoiding the page cache, particularly > > those with a working set that is significantly larger than available > > system memory. This patchset introduces _optional_ support to > > configure the use of O_DIRECT or DONTCACHE for NFSD's READ and WRITE > > support. The NFSD default to use page cache is left unchanged. > > > > The performance win associated with using NFSD DIRECT was previously > > summarized here: > > https://lore.kernel.org/linux-nfs/aEslwqa9iMeZjjlV@xxxxxxxxxx/ > > This picture offers a nice summary of performance gains: > > https://original.art/NFSD_direct_vs_buffered_IO.jpg > > > > [...] > > Applied to nfsd-testing, thanks! > > [01/13] NFSD: filecache: add STATX_DIOALIGN and STATX_DIO_READ_ALIGN support > commit: af157e09634a113da83d8ac5fff541f9e06ad653 > [05/13] NFSD: filecache: only get DIO alignment attrs if NFSD_IO_DIRECT enabled > commit: af157e09634a113da83d8ac5fff541f9e06ad653 I noticed you folded these, unfortunately that isn't bisect safe unless you pull these fs/nfsd/nfsd.h changes to the front too: git diff f76b72e4908c556021d94bdeca86fffce430c791^..a45da44bb6bade1dfef569c792ae2ee6507f4724 -- fs/nfsd/nfsd.h diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h index 1cd0bed57bc2..fe935b4cda53 100644 --- a/fs/nfsd/nfsd.h +++ b/fs/nfsd/nfsd.h @@ -153,6 +153,16 @@ static inline void nfsd_debugfs_exit(void) {} extern bool nfsd_disable_splice_read __read_mostly; +enum { + NFSD_IO_UNSPECIFIED = 0, + NFSD_IO_BUFFERED, + NFSD_IO_DONTCACHE, + NFSD_IO_DIRECT, +}; + +extern u64 nfsd_io_cache_read __read_mostly; +extern u64 nfsd_io_cache_write __read_mostly; + extern int nfsd_max_blksize; static inline int nfsd_v4client(struct svc_rqst *rq) > [02/13] NFSD: pass nfsd_file to nfsd_iter_read() > commit: 63a534c8b18642dc27318e08b77952c4d7f55628 > [03/13] NFSD: add io_cache_read controls to debugfs interface > commit: f76b72e4908c556021d94bdeca86fffce430c791 > [04/13] NFSD: add io_cache_write controls to debugfs interface > commit: a45da44bb6bade1dfef569c792ae2ee6507f4724 > [06/13] NFSD: issue READs using O_DIRECT even if IO is misaligned > commit: 6d80efb3cb6f9817bedfa460e9ddf56a916caf2f Thanks! Mike
