[PATCH 0/2] add block size > page size support to ramfs

[Pankaj Raghav (Samsung)]

From: Pankaj Raghav <p.raghav@xxxxxxxxxxx>

Add block size > page size to ramfs as we support minimum folio order
allocation in the page cache. The changes are very minimal, and this is
also a nice way to stress test just the page cache changes for minimum
folio order.

I tested the changes from blocksize 4k to 2M with ltp's fsx on an x86
machine.

I ran a basic perf test with dd as follows:
$ mount ramfs -t ramfs -o blocksize=$bs /media/test/
$ dd if=/mnt/rand of="/media/test/rand" bs=2M count=2048

+------+----------+
|  bs  | BW(GB/s) |
+------+----------+
| 4k   |      1.7 |
| 8k   |      2.4 |
| 16k  |      3.2 |
| 32k  |      4.0 |
| 64k  |      4.5 |
| 128k |      4.8 |
| 256k |      5.3 |
| 512k |      5.5 |
| 1M   |      5.6 |
| 2M   |      5.6 |
+------+----------+

We get better performance for larger bs as we allocate larger folios
instead of multiple smaller folios when there is no memory fragmentation
and pressure.

Pankaj Raghav (2):
  ramfs: add blocksize mount option
  ramfs: enable block size > page size

 fs/ramfs/inode.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)


base-commit: 4d0326b60bb753627437fff0f76bf1525bcda422
-- 
2.44.1