[lc-checkins] CVS: linux/mm filemap.c,1.31,1.32 memory.c,1.32,1.33 shmem.c,1.20,1.21 swap_state.c,1.34,1.35 vmscan.c,1.38,1.39

[Rodrigo S. de C. <rc...@us...>]

Update of /cvsroot/linuxcompressed/linux/mm
In directory usw-pr-cvs1:/tmp/cvs-serv27959/mm

Modified Files:
	filemap.c memory.c shmem.c swap_state.c vmscan.c 
Log Message:
Bug fixes
o Fixed potential oops in __read_cache_page() due to a misplaced
steal_page_from_comp_cache() call.
o Fixed bug in __read_swap_cache_async() which would end up getting an
extra reference on a swap cache page and would also erroneously stop a
swapin readahead.
o Fixed major bug in shrink_cache() that could hang the machine. We
could write a page in compress_dirty_page() even if the GFP mask does
not allow!

Cleanups
o Added #ifdefs to some flush_comp_cache() calls.
o Replaced find_comp_page() in do_swap_page() by a in_comp_cache()
call.

Other 
o Added page count check to shrink_comp_cache(). Only to make sure the
page is going to be actually freed.
o Removed write permission from /proc/sys/vm/comp_cache/size when
resize on demand option is enabled.



Index: filemap.c
===================================================================
RCS file: /cvsroot/linuxcompressed/linux/mm/filemap.c,v
retrieving revision 1.31
retrieving revision 1.32
diff -C2 -r1.31 -r1.32
*** filemap.c	1 Jul 2002 17:37:29 -0000	1.31
--- filemap.c	5 Jul 2002 15:21:49 -0000	1.32
***************
*** 164,171 ****
  #ifdef CONFIG_COMP_CACHE
  			if (PageTestandClearCompCache(page)) {
! 				if (PageMappedCompCache(page))
  					steal_page_from_comp_cache(page, NULL);
! 				else
! 					invalidate_comp_cache(mapping, page->index);
  			}
  #endif
--- 164,172 ----
  #ifdef CONFIG_COMP_CACHE
  			if (PageTestandClearCompCache(page)) {
! 				if (PageMappedCompCache(page)) {
  					steal_page_from_comp_cache(page, NULL);
! 					return;
! 				}
! 				invalidate_comp_cache(mapping, page->index);
  			}
  #endif
***************
*** 1107,1115 ****
  	}
  #ifdef CONFIG_COMP_PAGE_CACHE
- 	/*
- 	 * Invalidate compressed cache entry since it may become
- 	 * obsolete. The caller(s) will probably overwrite the data
- 	 * from this page, without dirtying the page.
- 	 */
  	if (page)
  		flush_comp_cache(page);
--- 1108,1111 ----
***************
*** 2946,2953 ****
  	if (cached_page)
  		page_cache_release(cached_page);
- 	steal_page_from_comp_cache(page, NULL);
  #ifdef CONFIG_COMP_PAGE_CACHE
! 	if (page)
  		flush_comp_cache(page);
  #endif
  	return page;
--- 2942,2950 ----
  	if (cached_page)
  		page_cache_release(cached_page);
  #ifdef CONFIG_COMP_PAGE_CACHE
! 	if (page) {
! 		steal_page_from_comp_cache(page, NULL);
  		flush_comp_cache(page);
+ 	}
  #endif
  	return page;
***************
*** 3011,3018 ****
  	}
  #ifdef CONFIG_COMP_PAGE_CACHE
- 	/*
- 	 * we have to invalidate the page since the caller function
- 	 * (generic_file_write) will overwrite the data in the page
- 	 */
  	flush_comp_cache(page);
  #endif
--- 3008,3011 ----

Index: memory.c
===================================================================
RCS file: /cvsroot/linuxcompressed/linux/mm/memory.c,v
retrieving revision 1.32
retrieving revision 1.33
diff -C2 -r1.32 -r1.33
*** memory.c	1 Jul 2002 17:37:29 -0000	1.32
--- memory.c	5 Jul 2002 15:21:49 -0000	1.33
***************
*** 1133,1139 ****
  	page = lookup_swap_cache(entry);
  	if (!page) {
- 		struct comp_cache_fragment * fragment;
  		/* perform readahead only if the page is on disk */
! 		if (find_comp_page(&swapper_space, entry.val, &fragment)) {
  			swapin_readahead(entry);
  			/* major fault */
--- 1133,1138 ----
  	page = lookup_swap_cache(entry);
  	if (!page) {
  		/* perform readahead only if the page is on disk */
! 		if (!in_comp_cache(&swapper_space, entry.val)) {
  			swapin_readahead(entry);
  			/* major fault */
***************
*** 1310,1314 ****
--- 1309,1315 ----
  		if (write_access) {
  			entry = pte_mkwrite(pte_mkdirty(entry));
+ #ifdef CONFIG_COMP_PAGE_CACHE
  			flush_comp_cache(new_page);
+ #endif
  		}
  		set_pte(page_table, entry);

Index: shmem.c
===================================================================
RCS file: /cvsroot/linuxcompressed/linux/mm/shmem.c,v
retrieving revision 1.20
retrieving revision 1.21
diff -C2 -r1.20 -r1.21
*** shmem.c	21 Mar 2002 19:24:17 -0000	1.20
--- shmem.c	5 Jul 2002 15:21:50 -0000	1.21
***************
*** 838,843 ****
  		if (IS_ERR(page))
  			break;
! 
  		flush_comp_cache(page);
  
  		/* We have exclusive IO access to the page.. */
--- 838,844 ----
  		if (IS_ERR(page))
  			break;
! #ifdef CONFIG_COMP_PAGE_CACHE
  		flush_comp_cache(page);
+ #endif
  
  		/* We have exclusive IO access to the page.. */

Index: swap_state.c
===================================================================
RCS file: /cvsroot/linuxcompressed/linux/mm/swap_state.c,v
retrieving revision 1.34
retrieving revision 1.35
diff -C2 -r1.34 -r1.35
*** swap_state.c	1 Jul 2002 21:36:50 -0000	1.34
--- swap_state.c	5 Jul 2002 15:21:50 -0000	1.35
***************
*** 134,138 ****
  	__delete_from_swap_cache(page);
  	spin_unlock(&pagecache_lock);
! 	
  	swap_free(entry);
  	page_cache_release(page);
--- 134,138 ----
  	__delete_from_swap_cache(page);
  	spin_unlock(&pagecache_lock);
! 
  	swap_free(entry);
  	page_cache_release(page);
***************
*** 221,227 ****
  
  		if (readahead) {
! 			struct page * tmp_page = find_get_page(&swapper_space, entry.val);
! 			if (tmp_page)
  				break;
  			if (in_comp_cache(&swapper_space, entry.val))
  				return new_page;
--- 221,229 ----
  
  		if (readahead) {
! 			found_page = find_get_page(&swapper_space, entry.val);
! 			if (found_page) {
! 				steal_page_from_comp_cache(found_page, new_page);
  				break;
+ 			}
  			if (in_comp_cache(&swapper_space, entry.val))
  				return new_page;
***************
*** 247,251 ****
  		}
  	} while (err != -ENOENT);
! 	
  	if (new_page)
  		page_cache_release(new_page);
--- 249,253 ----
  		}
  	} while (err != -ENOENT);
! 
  	if (new_page)
  		page_cache_release(new_page);

Index: vmscan.c
===================================================================
RCS file: /cvsroot/linuxcompressed/linux/mm/vmscan.c,v
retrieving revision 1.38
retrieving revision 1.39
diff -C2 -r1.38 -r1.39
*** vmscan.c	1 Jul 2002 18:44:40 -0000	1.38
--- vmscan.c	5 Jul 2002 15:21:52 -0000	1.39
***************
*** 410,418 ****
  
  			writepage = page->mapping->a_ops->writepage;
- #ifdef CONFIG_COMP_CACHE
- 			if (writepage)
- #else
  			if ((gfp_mask & __GFP_FS) && writepage)
- #endif
  			{
  				ClearPageDirty(page);
--- 410,414 ----
***************
*** 475,479 ****
  				UnlockPage(page);
  				page_cache_release(page);
! 				
  				spin_lock(&pagemap_lru_lock);
  				continue;
--- 471,475 ----
  				UnlockPage(page);
  				page_cache_release(page);
! 
  				spin_lock(&pagemap_lru_lock);
  				continue;