From ee615d4585cfc305bf6c218a62123c3051f8b4a3 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Fri, 29 Sep 2023 20:25:38 -0700 Subject: [PATCH] shmem: shrink shmem_inode_info: dir_offsets in a union Patch series "shmem,tmpfs: general maintenance". Mostly just cosmetic mods in mm/shmem.c, but the last two enforcing the "size=" limit better. 8/8 goes into percpu counter territory, and could stand alone. This patch (of 8): Shave 32 bytes off (the 64-bit) shmem_inode_info. There was a 4-byte pahole after stop_eviction, better filled by fsflags. And the 24-byte dir_offsets can only be used by directories, whereas shrinklist and swaplist only by shmem_mapping() inodes (regular files or long symlinks): so put those into a union. No change in mm/shmem.c is required for this. Link: https://lkml.kernel.org/r/c7441dc6-f3bb-dd60-c670-9f5cbd9f266@google.com Link: https://lkml.kernel.org/r/86ebb4b-c571-b9e8-27f5-cb82ec50357e@google.com Signed-off-by: Hugh Dickins Reviewed-by: Chuck Lever Reviewed-by: Jan Kara Cc: Axel Rasmussen Cc: Carlos Maiolino Cc: Christian Brauner Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Darrick J. Wong Cc: Dave Chinner Cc: Tim Chen Signed-off-by: Andrew Morton --- include/linux/shmem_fs.h | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index 6b0c626620f5c..2caa6b86106aa 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -23,18 +23,22 @@ struct shmem_inode_info { unsigned long flags; unsigned long alloced; /* data pages alloced to file */ unsigned long swapped; /* subtotal assigned to swap */ - pgoff_t fallocend; /* highest fallocate endindex */ - struct list_head shrinklist; /* shrinkable hpage inodes */ - struct list_head swaplist; /* chain of maybes on swap */ + union { + struct offset_ctx dir_offsets; /* stable directory offsets */ + struct { + struct list_head shrinklist; /* shrinkable hpage inodes */ + struct list_head swaplist; /* chain of maybes on swap */ + }; + }; + struct timespec64 i_crtime; /* file creation time */ struct shared_policy policy; /* NUMA memory alloc policy */ struct simple_xattrs xattrs; /* list of xattrs */ + pgoff_t fallocend; /* highest fallocate endindex */ + unsigned int fsflags; /* for FS_IOC_[SG]ETFLAGS */ atomic_t stop_eviction; /* hold when working on inode */ - struct timespec64 i_crtime; /* file creation time */ - unsigned int fsflags; /* flags for FS_IOC_[SG]ETFLAGS */ #ifdef CONFIG_TMPFS_QUOTA struct dquot *i_dquot[MAXQUOTAS]; #endif - struct offset_ctx dir_offsets; /* stable entry offsets */ struct inode vfs_inode; }; -- 2.30.2