Re: [PATCH 2/3] mm: Provide address_space operation for filling pages for read
From: Matthew Wilcox <willy@infradead.org>
Date: 2021-01-20 17:58:55
Also in:
linux-fsdevel
On Wed, Jan 20, 2021 at 05:28:36PM +0000, Christoph Hellwig wrote:
On Wed, Jan 20, 2021 at 06:27:05PM +0100, Jan Kara wrote:quoted
This would mean pulling i_mmap_sem out from ext4/XFS/F2FS private inode into the VFS inode. Which is fine by me but it would grow struct inode for proc / tmpfs / btrfs (although for btrfs I'm not convinced it isn't actually prone to the race and doesn't need similar protection as xfs / ext4) so some people may object.The btrfs folks are already looking into lifting it to common code. Also I have a patch pending to remove a list_head from the inode to counter the size increase :)
We can get rid of nrexceptional as well: https://lore.kernel.org/linux-fsdevel/20201026151849.24232-1-willy@infradead.org/ (local) We can also reduce the size of the rwsem by one word by replacing the list_head with a single pointer. https://git.infradead.org/users/willy/pagecache.git/shortlog/refs/heads/wlist (haven't touched it in almost four years, seemed to have a bug last time i looked at it).