From b46e0966741143366b5e9aafd3e85e297fd2f365 Mon Sep 17 00:00:00 2001 From: Joanne Koong Date: Wed, 16 Sep 2026 11:44:24 -0700 Subject: [PATCH] fuse: enable large folios Enable large folios, capping the max order at the largest request fuse can issue, so a folio always fits within a single request. The order range minimum is 0, so under memory pressure the allocator falls back to smaller folios. Benchmarks (libfuse passthrough_hp, buffered fio, single job, 4 GiB file, medians, NUMA-pinned, performance governor, strictlimiting on by default): tmpfs backing (page-cache bound): workload bs large folios off on delta seq read, cold, 128k 3110 MiB/s 4514 MiB/s +45% seq read, cold, 1M 3079 MiB/s 5181 MiB/s +68% seq read, warm, 128k 2438 MiB/s 4486 MiB/s +84% seq read, warm, 1M 2403 MiB/s 5123 MiB/s +113% writeback write, seq,128k 1211 MiB/s 1699 MiB/s +40% writeback write, seq, 1M 1462 MiB/s 2208 MiB/s +51% writeback write, rand,128k 1101 MiB/s 1757 MiB/s +60% + writeback write, rand, 1M 1284 MiB/s 2228 MiB/s +74% + xfs on NVMe backing (device bound for cold I/O): workload bs large folios off on delta seq read, cold, 128k 2030 MiB/s 2172 MiB/s +7% * seq read, cold, 1M 1999 MiB/s 2181 MiB/s +9% * seq read, warm, 128k 2451 MiB/s 4939 MiB/s +101% seq read, warm, 1M 2340 MiB/s 5639 MiB/s +141% writeback write, seq,128k 637 MiB/s 747 MiB/s +17% * writeback write, seq, 1M 694 MiB/s 833 MiB/s +20% * writeback write, rand,128k 1004 MiB/s 1648 MiB/s +64% + writeback write, rand, 1M 1171 MiB/s 2055 MiB/s +75% + (*) device-bandwidth bound. Not much throughput gain but system cpu utilization was roughly halved (+) random write was tested as an overwrite of a hot region (under writeback, this is page-cache bound, so the gain comes from lower per-folio cpu overhead rather than higher backing-device throughput) Random reads (4k and 128k) and writethrough writes were neutral with no regression (no read-modify-write or read-amplification penalty from large folios) More information about the benchmark setup and results are in https://github.com/joannekoong/linux/commits/fuse_large_folios_benchmarks/ Reviewed-by: Horst Birthelmer Reviewed-by: Jingbo Xu Signed-off-by: Joanne Koong Signed-off-by: Miklos Szeredi --- fs/fuse/file.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 8083404f4cbc..c5e77e13bfdc 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -3140,6 +3140,7 @@ void fuse_init_file_inode(struct inode *inode, unsigned int flags) { struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_conn *fc = get_fuse_conn(inode); + unsigned int max_folio_pages; inode->i_fop = &fuse_file_operations; inode->i_data.a_ops = &fuse_file_aops; @@ -3155,4 +3156,18 @@ void fuse_init_file_inode(struct inode *inode, unsigned int flags) if (IS_ENABLED(CONFIG_FUSE_DAX)) fuse_dax_inode_init(inode, flags); + + if (FUSE_IS_DAX(inode)) + return; + + /* + * A folio is never split across requests so cap the order so that one + * always fits in a single request. + */ + max_folio_pages = min3(fc->max_write >> PAGE_SHIFT, + fc->max_read >> PAGE_SHIFT, fc->max_pages); + + if (max_folio_pages) + mapping_set_folio_order_range(inode->i_mapping, 0, + ilog2(max_folio_pages)); }