diff options
Diffstat (limited to 'mm/shmem.c')
| -rw-r--r-- | mm/shmem.c | 102 |
1 files changed, 85 insertions, 17 deletions
@@ -14,31 +14,39 @@ * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net> * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> * + * tiny-shmem: + * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com> + * * This file is released under the GPL. */ +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/vfs.h> +#include <linux/mount.h> +#include <linux/file.h> +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/swap.h> + +static struct vfsmount *shm_mnt; + +#ifdef CONFIG_SHMEM /* * This virtual memory filesystem is heavily based on the ramfs. It * extends ramfs by the ability to use swap and honor resource limits * which makes it a completely usable filesystem. */ -#include <linux/module.h> -#include <linux/init.h> -#include <linux/fs.h> #include <linux/xattr.h> #include <linux/exportfs.h> #include <linux/generic_acl.h> -#include <linux/mm.h> #include <linux/mman.h> -#include <linux/file.h> -#include <linux/swap.h> #include <linux/pagemap.h> #include <linux/string.h> #include <linux/slab.h> #include <linux/backing-dev.h> #include <linux/shmem_fs.h> -#include <linux/mount.h> #include <linux/writeback.h> #include <linux/vfs.h> #include <linux/blkdev.h> @@ -920,7 +928,11 @@ found: error = 1; if (!inode) goto out; - /* Precharge page using GFP_KERNEL while we can wait */ + /* + * Charge page using GFP_KERNEL while we can wait. + * Charged back to the user(not to caller) when swap account is used. + * add_to_page_cache() will be called with GFP_NOWAIT. + */ error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL); if (error) goto out; @@ -1312,15 +1324,19 @@ repeat: } else { shmem_swp_unmap(entry); spin_unlock(&info->lock); - unlock_page(swappage); - page_cache_release(swappage); if (error == -ENOMEM) { /* allow reclaim from this memory cgroup */ - error = mem_cgroup_shrink_usage(current->mm, + error = mem_cgroup_shrink_usage(swappage, + current->mm, gfp); - if (error) + if (error) { + unlock_page(swappage); + page_cache_release(swappage); goto failed; + } } + unlock_page(swappage); + page_cache_release(swappage); goto repeat; } } else if (sgp == SGP_READ && !filepage) { @@ -1371,7 +1387,7 @@ repeat: /* Precharge page while we can wait, compensate after */ error = mem_cgroup_cache_charge(filepage, current->mm, - gfp & ~__GFP_HIGHMEM); + GFP_KERNEL); if (error) { page_cache_release(filepage); shmem_unacct_blocks(info->flags, 1); @@ -1444,7 +1460,6 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) if (error) return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); - mark_page_accessed(vmf->page); return ret | VM_FAULT_LOCKED; } @@ -2486,7 +2501,6 @@ static struct file_system_type tmpfs_fs_type = { .get_sb = shmem_get_sb, .kill_sb = kill_litter_super, }; -static struct vfsmount *shm_mnt; static int __init init_tmpfs(void) { @@ -2525,7 +2539,51 @@ out4: shm_mnt = ERR_PTR(error); return error; } -module_init(init_tmpfs) + +#else /* !CONFIG_SHMEM */ + +/* + * tiny-shmem: simple shmemfs and tmpfs using ramfs code + * + * This is intended for small system where the benefits of the full + * shmem code (swap-backed and resource-limited) are outweighed by + * their complexity. On systems without swap this code should be + * effectively equivalent, but much lighter weight. + */ + +#include <linux/ramfs.h> + +static struct file_system_type tmpfs_fs_type = { + .name = "tmpfs", + .get_sb = ramfs_get_sb, + .kill_sb = kill_litter_super, +}; + +static int __init init_tmpfs(void) +{ + BUG_ON(register_filesystem(&tmpfs_fs_type) != 0); + + shm_mnt = kern_mount(&tmpfs_fs_type); + BUG_ON(IS_ERR(shm_mnt)); + + return 0; +} + +int shmem_unuse(swp_entry_t entry, struct page *page) +{ + return 0; +} + +#define shmem_file_operations ramfs_file_operations +#define shmem_vm_ops generic_file_vm_ops +#define shmem_get_inode ramfs_get_inode +#define shmem_acct_size(a, b) 0 +#define shmem_unacct_size(a, b) do {} while (0) +#define SHMEM_MAX_BYTES LLONG_MAX + +#endif /* CONFIG_SHMEM */ + +/* common code */ /** * shmem_file_setup - get an unlinked file living in tmpfs @@ -2569,12 +2627,20 @@ struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) if (!inode) goto close_file; +#ifdef CONFIG_SHMEM SHMEM_I(inode)->flags = flags & VM_ACCOUNT; +#endif d_instantiate(dentry, inode); inode->i_size = size; inode->i_nlink = 0; /* It is unlinked */ init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ, - &shmem_file_operations); + &shmem_file_operations); + +#ifndef CONFIG_MMU + error = ramfs_nommu_expand_for_mapping(inode, size); + if (error) + goto close_file; +#endif return file; close_file: @@ -2606,3 +2672,5 @@ int shmem_zero_setup(struct vm_area_struct *vma) vma->vm_ops = &shmem_vm_ops; return 0; } + +module_init(init_tmpfs) |
