Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965012AbXAJSFm (ORCPT ); Wed, 10 Jan 2007 13:05:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965013AbXAJSFm (ORCPT ); Wed, 10 Jan 2007 13:05:42 -0500 Received: from 3a.49.1343.static.theplanet.com ([67.19.73.58]:47572 "EHLO pug.o-hand.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965012AbXAJSFY (ORCPT ); Wed, 10 Jan 2007 13:05:24 -0500 Subject: [PATCH 2/4] swap: Add try_to_unuse_page_entry() From: Richard Purdie To: Nick Piggin , Hugh Dickins , kernel list Cc: Andrew Morton Content-Type: text/plain Date: Wed, 10 Jan 2007 18:05:20 +0000 Message-Id: <1168452321.5801.60.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4472 Lines: 139 Add try_to_unuse_page_entry() which can be used to unuse page entries. This needs try_to_unuse_anon() which is also added, similar to try_to_unmap_anon(). Originally based on a patch by Nick Piggin from LKML with changes of my own after hints from Hugh Dickins. Signed-off-by: Richard Purdie --- include/linux/rmap.h | 6 +++++ include/linux/swap.h | 1 mm/rmap.c | 2 - mm/swapfile.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 63 insertions(+), 1 deletion(-) Index: git/mm/swapfile.c =================================================================== --- git.orig/mm/swapfile.c 2007-01-10 16:44:13.000000000 +0000 +++ git/mm/swapfile.c 2007-01-10 16:53:59.000000000 +0000 @@ -646,6 +646,61 @@ static int unuse_mm(struct mm_struct *mm return 0; } +static int try_to_unuse_anon(swp_entry_t entry, struct page *page) +{ + struct anon_vma *anon_vma; + struct vm_area_struct *vma; + + anon_vma = page_lock_anon_vma(page); + if (!anon_vma) + return 0; + + list_for_each_entry(vma, &anon_vma->head, anon_vma_node) { + if (unuse_vma(vma, entry, page)) + break; + } + spin_unlock(&anon_vma->lock); + return 0; +} + + +void try_to_unuse_page_entry(struct page *page) +{ + struct swap_info_struct *si; + unsigned short *swap_map; + swp_entry_t entry; + + BUG_ON(!PageLocked(page)); + BUG_ON(!PageSwapCache(page)); + BUG_ON(PageWriteback(page)); + BUG_ON(PagePrivate(page)); + + entry.val = page_private(page); + si = swap_info_get(entry); + if (!si) { + WARN_ON(1); + return; + } + swap_map = &si->swap_map[swp_offset(entry)]; + spin_unlock(&swap_lock); + + BUG_ON(*swap_map == SWAP_MAP_BAD); + + if (!shmem_unuse(entry, page)) { + try_to_unuse_anon(entry, page); + delete_from_swap_cache(page); + } else if (PageSwapCache(page)) { + /* + * shmem_unuse deleted a swappage from the swap cache, but the + * move to filepage failed so it left swappage in cache and + * lowered its swap count to pass quickly through the loops in + * try_to_unuse(). We must reincrement the count to try again + * later (ick). + */ + swap_duplicate(entry); + } +} + /* * Scan swap_map from current position to next entry still in use. * Recycle to start on reaching the end, returning 0 when empty. Index: git/include/linux/rmap.h =================================================================== --- git.orig/include/linux/rmap.h 2007-01-10 16:37:04.000000000 +0000 +++ git/include/linux/rmap.h 2007-01-10 16:48:02.000000000 +0000 @@ -104,6 +104,11 @@ pte_t *page_check_address(struct page *, unsigned long page_address_in_vma(struct page *, struct vm_area_struct *); /* + * Used by try_to_unuse_anon() and try_to_unmap_anon() + */ +struct anon_vma *page_lock_anon_vma(struct page *page); + +/* * Cleans the PTEs of shared mappings. * (and since clean PTEs should also be readonly, write protects them too) * @@ -125,6 +130,7 @@ static inline int page_mkclean(struct pa return 0; } +#define page_lock_anon_vma(page) (0) #endif /* CONFIG_MMU */ Index: git/mm/rmap.c =================================================================== --- git.orig/mm/rmap.c 2007-01-10 16:37:04.000000000 +0000 +++ git/mm/rmap.c 2007-01-10 16:48:02.000000000 +0000 @@ -181,7 +181,7 @@ void __init anon_vma_init(void) * Getting a lock on a stable anon_vma from a page off the LRU is * tricky: page_lock_anon_vma rely on RCU to guard against the races. */ -static struct anon_vma *page_lock_anon_vma(struct page *page) +struct anon_vma *page_lock_anon_vma(struct page *page) { struct anon_vma *anon_vma = NULL; unsigned long anon_mapping; Index: git/include/linux/swap.h =================================================================== --- git.orig/include/linux/swap.h 2007-01-10 16:44:13.000000000 +0000 +++ git/include/linux/swap.h 2007-01-10 16:48:02.000000000 +0000 @@ -252,6 +252,7 @@ extern sector_t swapdev_block(int, pgoff extern struct swap_info_struct *get_swap_info_struct(unsigned); extern int can_share_swap_page(struct page *); extern int remove_exclusive_swap_page(struct page *); +extern void try_to_unuse_page_entry(struct page *page); struct backing_dev_info; extern spinlock_t swap_lock; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/