From d614d3153f8acc606f0c0644831b7c0d359a6b2c Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Mon, 19 Apr 2004 17:22:03 -0700 Subject: [PATCH] [PATCH] fix madvise(MADV_DONTNEED) for nonlinear vmas From: Hugh Dickins Jamie points out that madvise(MADV_DONTNEED) should unmap pages from a nonlinear area in such a way that the nonlinear offsets are preserved if the pages do turn out to be needed later after all, instead of reverting them to linearity: needs to pass down a zap_details block. (But this still leaves mincore unaware of nonlinear vmas: bigger job.) --- include/linux/mm.h | 11 ++++++++++- mm/madvise.c | 11 ++++++++++- mm/memory.c | 10 ---------- 3 files changed, 20 insertions(+), 12 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index d664c4ffbcc7..103f14358d1f 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -439,7 +439,16 @@ struct file *shmem_file_setup(char * name, loff_t size, unsigned long flags); void shmem_lock(struct file * file, int lock); int shmem_zero_setup(struct vm_area_struct *); -struct zap_details; +/* + * Parameter block passed down to zap_pte_range in exceptional cases. + */ +struct zap_details { + struct vm_area_struct *nonlinear_vma; /* Check page->index if set */ + struct address_space *check_mapping; /* Check page->mapping if set */ + pgoff_t first_index; /* Lowest page->index to unmap */ + pgoff_t last_index; /* Highest page->index to unmap */ +}; + void zap_page_range(struct vm_area_struct *vma, unsigned long address, unsigned long size, struct zap_details *); int unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm, diff --git a/mm/madvise.c b/mm/madvise.c index bfb431950371..81c4ea30c75e 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -92,10 +92,19 @@ static long madvise_willneed(struct vm_area_struct * vma, static long madvise_dontneed(struct vm_area_struct * vma, unsigned long start, unsigned long end) { + struct zap_details details; + if (vma->vm_flags & VM_LOCKED) return -EINVAL; - zap_page_range(vma, start, end - start, NULL); + if (unlikely(vma->vm_flags & VM_NONLINEAR)) { + details.check_mapping = NULL; + details.nonlinear_vma = vma; + details.first_index = 0; + details.last_index = ULONG_MAX; + zap_page_range(vma, start, end - start, &details); + } else + zap_page_range(vma, start, end - start, NULL); return 0; } diff --git a/mm/memory.c b/mm/memory.c index e54939da2caf..5ae7c99aeaa5 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -384,16 +384,6 @@ nomem: return -ENOMEM; } -/* - * Parameter block passed down to zap_pte_range in exceptional cases. - */ -struct zap_details { - struct vm_area_struct *nonlinear_vma; /* Check page->index if set */ - struct address_space *check_mapping; /* Check page->mapping if set */ - pgoff_t first_index; /* Lowest page->index to unmap */ - pgoff_t last_index; /* Highest page->index to unmap */ -}; - static void zap_pte_range(struct mmu_gather *tlb, pmd_t *pmd, unsigned long address, unsigned long size, struct zap_details *details) -- 2.39.5