mm/rmap: extend rmap_walk_xxx() to cope with different cases
There are a lot of common parts in traversing functions, but there are also a little of uncommon parts in it. By assigning proper function pointer on each rmap_walker_control, we can handle these difference correctly. Following are differences we should handle. 1. difference of lock function in anon mapping case 2. nonlinear handling in file mapping case 3. prechecked condition: checking memcg in page_referenced(), checking VM_SHARE in page_mkclean() checking temporary vma in try_to_unmap() 4. exit condition: checking page_mapped() in try_to_unmap() So, in this patch, I introduce 4 function pointers to handle above differences. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Hillf Danton <dhillf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -235,10 +235,25 @@ struct anon_vma *page_lock_anon_vma_read(struct page *page);
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void page_unlock_anon_vma_read(struct anon_vma *anon_vma);
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void page_unlock_anon_vma_read(struct anon_vma *anon_vma);
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int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);
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int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);
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/*
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* rmap_walk_control: To control rmap traversing for specific needs
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*
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* arg: passed to rmap_one() and invalid_vma()
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* rmap_one: executed on each vma where page is mapped
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* done: for checking traversing termination condition
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* file_nonlinear: for handling file nonlinear mapping
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* anon_lock: for getting anon_lock by optimized way rather than default
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* invalid_vma: for skipping uninterested vma
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*/
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struct rmap_walk_control {
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struct rmap_walk_control {
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void *arg;
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void *arg;
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int (*rmap_one)(struct page *page, struct vm_area_struct *vma,
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int (*rmap_one)(struct page *page, struct vm_area_struct *vma,
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unsigned long addr, void *arg);
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unsigned long addr, void *arg);
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int (*done)(struct page *page);
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int (*file_nonlinear)(struct page *, struct address_space *,
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struct vm_area_struct *vma);
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struct anon_vma *(*anon_lock)(struct page *page);
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bool (*invalid_vma)(struct vm_area_struct *vma, void *arg);
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};
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};
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/*
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/*
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7
mm/ksm.c
7
mm/ksm.c
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@ -2032,12 +2032,19 @@ again:
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if ((rmap_item->mm == vma->vm_mm) == search_new_forks)
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if ((rmap_item->mm == vma->vm_mm) == search_new_forks)
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continue;
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continue;
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if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg))
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continue;
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ret = rwc->rmap_one(page, vma,
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ret = rwc->rmap_one(page, vma,
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rmap_item->address, rwc->arg);
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rmap_item->address, rwc->arg);
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if (ret != SWAP_AGAIN) {
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if (ret != SWAP_AGAIN) {
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anon_vma_unlock_read(anon_vma);
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anon_vma_unlock_read(anon_vma);
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goto out;
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goto out;
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}
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}
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if (rwc->done && rwc->done(page)) {
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anon_vma_unlock_read(anon_vma);
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goto out;
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}
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}
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}
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anon_vma_unlock_read(anon_vma);
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anon_vma_unlock_read(anon_vma);
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}
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}
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37
mm/rmap.c
37
mm/rmap.c
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@ -1684,10 +1684,14 @@ void __put_anon_vma(struct anon_vma *anon_vma)
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}
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}
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#ifdef CONFIG_MIGRATION
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#ifdef CONFIG_MIGRATION
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static struct anon_vma *rmap_walk_anon_lock(struct page *page)
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static struct anon_vma *rmap_walk_anon_lock(struct page *page,
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struct rmap_walk_control *rwc)
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{
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{
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struct anon_vma *anon_vma;
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struct anon_vma *anon_vma;
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if (rwc->anon_lock)
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return rwc->anon_lock(page);
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/*
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/*
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* Note: remove_migration_ptes() cannot use page_lock_anon_vma_read()
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* Note: remove_migration_ptes() cannot use page_lock_anon_vma_read()
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* because that depends on page_mapped(); but not all its usages
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* because that depends on page_mapped(); but not all its usages
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@ -1713,16 +1717,22 @@ static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc)
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struct anon_vma_chain *avc;
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struct anon_vma_chain *avc;
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int ret = SWAP_AGAIN;
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int ret = SWAP_AGAIN;
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anon_vma = rmap_walk_anon_lock(page);
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anon_vma = rmap_walk_anon_lock(page, rwc);
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if (!anon_vma)
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if (!anon_vma)
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return ret;
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return ret;
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anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
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anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
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struct vm_area_struct *vma = avc->vma;
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struct vm_area_struct *vma = avc->vma;
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unsigned long address = vma_address(page, vma);
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unsigned long address = vma_address(page, vma);
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if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg))
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continue;
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ret = rwc->rmap_one(page, vma, address, rwc->arg);
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ret = rwc->rmap_one(page, vma, address, rwc->arg);
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if (ret != SWAP_AGAIN)
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if (ret != SWAP_AGAIN)
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break;
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break;
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if (rwc->done && rwc->done(page))
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break;
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}
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}
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anon_vma_unlock_read(anon_vma);
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anon_vma_unlock_read(anon_vma);
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return ret;
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return ret;
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@ -1740,15 +1750,26 @@ static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc)
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mutex_lock(&mapping->i_mmap_mutex);
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mutex_lock(&mapping->i_mmap_mutex);
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vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
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vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
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unsigned long address = vma_address(page, vma);
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unsigned long address = vma_address(page, vma);
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if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg))
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continue;
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ret = rwc->rmap_one(page, vma, address, rwc->arg);
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ret = rwc->rmap_one(page, vma, address, rwc->arg);
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if (ret != SWAP_AGAIN)
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if (ret != SWAP_AGAIN)
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break;
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goto done;
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if (rwc->done && rwc->done(page))
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goto done;
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}
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}
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/*
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* No nonlinear handling: being always shared, nonlinear vmas
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if (!rwc->file_nonlinear)
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* never contain migration ptes. Decide what to do about this
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goto done;
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* limitation to linear when we need rmap_walk() on nonlinear.
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*/
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if (list_empty(&mapping->i_mmap_nonlinear))
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goto done;
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ret = rwc->file_nonlinear(page, mapping, vma);
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done:
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mutex_unlock(&mapping->i_mmap_mutex);
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mutex_unlock(&mapping->i_mmap_mutex);
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return ret;
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return ret;
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}
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}
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