On 1/5/24 11:13, Viacheslav Dubeyko wrote: > >> On Jan 5, 2024, at 12:17 AM, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: >> >> The memalloc_nofs APIs were introduced in May 2017, but we still have >> over 1000 uses of GFP_NOFS in fs/ today (and 200 outside fs/, which is >> really sad). This session is for filesystem developers to talk about >> what they need to do to fix up their own filesystem, or share stories >> about how they made their filesystem better by adopting the new APIs. >> > > Many file systems are still heavily using GFP_NOFS for kmalloc and > kmem_cache_alloc family methods even if memalloc_nofs_save() and > memalloc_nofs_restore() pair is used too. But I can see that GFP_NOFS Yes it should be enough to rely on memalloc_nofs_save() for kmalloc/kmem_cache_alloc. The kmalloc layer doesnt't care about it, and once it's run out of available slab folios and calls into the page allocator for a new one, it evaluates the effect of memalloc_nofs_save() as expected. > is used in radix_tree_preload(), bio_alloc(), posix_acl_clone(), > sb_issue_zeroout, sb_issue_discard(), alloc_inode_sb(), blkdev_issue_zeroout(), > blkdev_issue_secure_erase(), blkdev_zone_mgmt(), etc. > > Would it be safe to switch on memalloc_nofs_save()/memalloc_nofs_restore() for > all possible cases? Any potential issues or downsides? > > Thanks, > Slava. > >
