diff options
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 74 |
1 files changed, 45 insertions, 29 deletions
@@ -3,24 +3,17 @@ * * Written by obz. */ -#include <linux/stat.h> -#include <linux/sched.h> -#include <linux/kernel.h> -#include <linux/mm.h> #include <linux/slab.h> #include <linux/shm.h> -#include <linux/errno.h> #include <linux/mman.h> -#include <linux/string.h> #include <linux/pagemap.h> #include <linux/swap.h> -#include <linux/smp.h> +#include <linux/swapctl.h> #include <linux/smp_lock.h> #include <linux/init.h> #include <linux/file.h> #include <asm/uaccess.h> -#include <asm/system.h> #include <asm/pgtable.h> /* description of effects of mapping type and prot in current implementation. @@ -57,6 +50,12 @@ int vm_enough_memory(long pages) * simple, it hopefully works in most obvious cases.. Easy to * fool it, but this should catch most mistakes. */ + /* 23/11/98 NJC: Somewhat less stupid version of algorithm, + * which tries to do "TheRightThing". Instead of using half of + * (buffers+cache), use the minimum values. Allow an extra 2% + * of num_physpages for safety margin. + */ + long free; /* Sometimes we want to use more memory than we have. */ @@ -65,10 +64,9 @@ int vm_enough_memory(long pages) free = buffermem >> PAGE_SHIFT; free += page_cache_size; - free >>= 1; free += nr_free_pages; free += nr_swap_pages; - free -= num_physpages >> 4; + free -= (page_cache.min_percent + buffer_mem.min_percent + 2)*num_physpages/100; return free > pages; } @@ -93,7 +91,21 @@ asmlinkage unsigned long sys_brk(unsigned long brk) struct mm_struct *mm = current->mm; down(&mm->mmap_sem); + + /* + * This lock-kernel is one of the main contention points for + * certain normal loads. And it really should not be here: almost + * everything in brk()/mmap()/munmap() is protected sufficiently by + * the mmap semaphore that we got above. + * + * We should move this into the few things that really want the + * lock, namely anything that actually touches a file descriptor + * etc. We can do all the normal anonymous mapping cases without + * ever getting the lock at all - the actual memory management + * code is already completely thread-safe. + */ lock_kernel(); + if (brk < mm->end_code) goto out; newbrk = PAGE_ALIGN(brk); @@ -162,7 +174,7 @@ unsigned long do_mmap(struct file * file, unsigned long addr, unsigned long len, { struct mm_struct * mm = current->mm; struct vm_area_struct * vma; - int correct_wcount = 0, error; + int error; if ((len = PAGE_ALIGN(len)) == 0) return addr; @@ -286,30 +298,28 @@ unsigned long do_mmap(struct file * file, unsigned long addr, unsigned long len, !vm_enough_memory(len >> PAGE_SHIFT)) goto free_vma; - error = 0; if (file) { + int correct_wcount = 0; if (vma->vm_flags & VM_DENYWRITE) { - if (file->f_dentry->d_inode->i_writecount > 0) + if (file->f_dentry->d_inode->i_writecount > 0) { error = -ETXTBSY; - else { - /* f_op->mmap might possibly sleep - * (generic_file_mmap doesn't, but other code - * might). In any case, this takes care of any - * race that this might cause. - */ - file->f_dentry->d_inode->i_writecount--; - correct_wcount = 1; + goto free_vma; } + /* f_op->mmap might possibly sleep + * (generic_file_mmap doesn't, but other code + * might). In any case, this takes care of any + * race that this might cause. + */ + file->f_dentry->d_inode->i_writecount--; + correct_wcount = 1; } - if (!error) - error = file->f_op->mmap(file, vma); - + error = file->f_op->mmap(file, vma); + /* Fix up the count if necessary, then check for an error */ + if (correct_wcount) + file->f_dentry->d_inode->i_writecount++; + if (error) + goto unmap_and_free_vma; } - /* Fix up the count if necessary, then check for an error */ - if (correct_wcount) - file->f_dentry->d_inode->i_writecount++; - if (error) - goto free_vma; /* * merge_segments may merge our vma, so we can't refer to it @@ -327,6 +337,11 @@ unsigned long do_mmap(struct file * file, unsigned long addr, unsigned long len, } return addr; +unmap_and_free_vma: + /* Undo any partial mapping done by a device driver. */ + flush_cache_range(mm, vma->vm_start, vma->vm_end); + zap_page_range(mm, vma->vm_start, vma->vm_end - vma->vm_start); + flush_tlb_range(mm, vma->vm_start, vma->vm_end); free_vma: kmem_cache_free(vm_area_cachep, vma); return error; @@ -418,6 +433,7 @@ static int unmap_fixup(struct vm_area_struct *area, unsigned long addr, mpnt->vm_ops = area->vm_ops; mpnt->vm_offset = area->vm_offset + (end - area->vm_start); mpnt->vm_file = area->vm_file; + mpnt->vm_pte = area->vm_pte; if (mpnt->vm_file) mpnt->vm_file->f_count++; if (mpnt->vm_ops && mpnt->vm_ops->open) |