On 2024/9/22 8:35, Matthew Wilcox wrote:
On Fri, Sep 20, 2024 at 10:36:54PM +0800, Kefeng Wang wrote:
The tmpfs supports large folio, but there is some configurable options
to enable/disable large folio allocation, and for huge=within_size,
large folio only allowabled if it fully within i_size, so there is
performance issue when perform write without large folio, the issue is
similar to commit 4e527d5841e2 ("iomap: fault in smaller chunks for
non-large folio mappings").
No. What's wrong with my earlier suggestion?
The tempfs has mount options(never/always/within_size/madvise) for large
folio, also has sysfs file /sys/kernel/mm/transparent_hugepage/shmem_enabled
to deny/force large folio at runtime, as replied in v1, I think it
breaks the rules of mapping_set_folio_order_range(),
"Do not tune it based on, eg, i_size."
--- for tmpfs, it does choose large folio or not based on the i_size
"Context: This should not be called while the inode is active as it
is non-atomic."
--- during perform write, the inode is active
So this is why I don't use mapping_set_folio_order_range() here, but
correct me if I am wrong.
