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mm: code cleanup for MADV_FREE

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Some comments for MADV_FREE is revised and added to help people understand
the MADV_FREE code, especially the page flag, PG_swapbacked.  This makes
page_is_file_cache() isn't consistent with its comments.  So the function
is renamed to page_is_file_lru() to make them consistent again.  All these
are put in one patch as one logical change.

Suggested-by: David Hildenbrand <david@redhat.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: David Rientjes <rientjes@google.com>
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@kernel.org>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/20200317100342.2730705-1-ying.huang@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Huang Ying 2020-04-06 20:04:41 -07:00 committed by Linus Torvalds
parent 7a9547fd4e
commit 9de4f22a60
13 changed files with 44 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
include/linux/mm_inline.h
View File

@ -6,19 +6,20 @@
#include <linux/swap.h> #include <linux/swap.h>
/** /**
* page_is_file_cache - should the page be on a file LRU or anon LRU? * page_is_file_lru - should the page be on a file LRU or anon LRU?
* @page: the page to test * @page: the page to test
* *
* Returns 1 if @page is page cache page backed by a regular filesystem, * Returns 1 if @page is a regular filesystem backed page cache page or a lazily
* or 0 if @page is anonymous, tmpfs or otherwise ram or swap backed. * freed anonymous page (e.g. via MADV_FREE). Returns 0 if @page is a normal
* Used by functions that manipulate the LRU lists, to sort a page * anonymous page, a tmpfs page or otherwise ram or swap backed page. Used by
* onto the right LRU list. * functions that manipulate the LRU lists, to sort a page onto the right LRU
* list.
* *
* We would like to get this info without a page flag, but the state * We would like to get this info without a page flag, but the state
* needs to survive until the page is last deleted from the LRU, which * needs to survive until the page is last deleted from the LRU, which
* could be as far down as __page_cache_release. * could be as far down as __page_cache_release.
*/ */
static inline int page_is_file_cache(struct page *page) static inline int page_is_file_lru(struct page *page)
{ {
return !PageSwapBacked(page); return !PageSwapBacked(page);
} }
@ -75,7 +76,7 @@ static __always_inline void del_page_from_lru_list(struct page *page,
*/ */
static inline enum lru_list page_lru_base_type(struct page *page) static inline enum lru_list page_lru_base_type(struct page *page)
{ {
if (page_is_file_cache(page)) if (page_is_file_lru(page))
return LRU_INACTIVE_FILE; return LRU_INACTIVE_FILE;
return LRU_INACTIVE_ANON; return LRU_INACTIVE_ANON;
} }

5
include/linux/page-flags.h
View File

@ -63,6 +63,11 @@
* page_waitqueue(page) is a wait queue of all tasks waiting for the page * page_waitqueue(page) is a wait queue of all tasks waiting for the page
* to become unlocked. * to become unlocked.
* *
* PG_swapbacked is set when a page uses swap as a backing storage. This are
* usually PageAnon or shmem pages but please note that even anonymous pages
* might lose their PG_swapbacked flag when they simply can be dropped (e.g. as
* a result of MADV_FREE).
*
* PG_uptodate tells whether the page's contents is valid. When a read * PG_uptodate tells whether the page's contents is valid. When a read
* completes, the page becomes uptodate, unless a disk I/O error happened. * completes, the page becomes uptodate, unless a disk I/O error happened.
* *

2
include/trace/events/vmscan.h
View File

@ -323,7 +323,7 @@ TRACE_EVENT(mm_vmscan_writepage,
TP_fast_assign( TP_fast_assign(
__entry->pfn = page_to_pfn(page); __entry->pfn = page_to_pfn(page);
__entry->reclaim_flags = trace_reclaim_flags( __entry->reclaim_flags = trace_reclaim_flags(
page_is_file_cache(page)); page_is_file_lru(page));
), ),
TP_printk("page=%p pfn=%lu flags=%s", TP_printk("page=%p pfn=%lu flags=%s",

2
mm/compaction.c
View File

@ -989,7 +989,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
/* Successfully isolated */ /* Successfully isolated */
del_page_from_lru_list(page, lruvec, page_lru(page)); del_page_from_lru_list(page, lruvec, page_lru(page));
mod_node_page_state(page_pgdat(page), mod_node_page_state(page_pgdat(page),
NR_ISOLATED_ANON + page_is_file_cache(page), NR_ISOLATED_ANON + page_is_file_lru(page),
hpage_nr_pages(page)); hpage_nr_pages(page));
isolate_success: isolate_success:

2
mm/gup.c
View File

@ -1677,7 +1677,7 @@ check_again:
list_add_tail(&head->lru, &cma_page_list); list_add_tail(&head->lru, &cma_page_list);
mod_node_page_state(page_pgdat(head), mod_node_page_state(page_pgdat(head),
NR_ISOLATED_ANON + NR_ISOLATED_ANON +
page_is_file_cache(head), page_is_file_lru(head),
hpage_nr_pages(head)); hpage_nr_pages(head));
} }
} }

4
mm/khugepaged.c
View File

@ -511,7 +511,7 @@ void __khugepaged_exit(struct mm_struct *mm)
static void release_pte_page(struct page *page) static void release_pte_page(struct page *page)
{ {
dec_node_page_state(page, NR_ISOLATED_ANON + page_is_file_cache(page)); dec_node_page_state(page, NR_ISOLATED_ANON + page_is_file_lru(page));
unlock_page(page); unlock_page(page);
putback_lru_page(page); putback_lru_page(page);
} }
@ -611,7 +611,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
goto out; goto out;
} }
inc_node_page_state(page, inc_node_page_state(page,
NR_ISOLATED_ANON + page_is_file_cache(page)); NR_ISOLATED_ANON + page_is_file_lru(page));
VM_BUG_ON_PAGE(!PageLocked(page), page); VM_BUG_ON_PAGE(!PageLocked(page), page);
VM_BUG_ON_PAGE(PageLRU(page), page); VM_BUG_ON_PAGE(PageLRU(page), page);

2
mm/memory-failure.c
View File

@ -1810,7 +1810,7 @@ static int __soft_offline_page(struct page *page, int flags)
*/ */
if (!__PageMovable(page)) if (!__PageMovable(page))
inc_node_page_state(page, NR_ISOLATED_ANON + inc_node_page_state(page, NR_ISOLATED_ANON +
page_is_file_cache(page)); page_is_file_lru(page));
list_add(&page->lru, &pagelist); list_add(&page->lru, &pagelist);
ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL, ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL,
MIGRATE_SYNC, MR_MEMORY_FAILURE); MIGRATE_SYNC, MR_MEMORY_FAILURE);

2
mm/memory_hotplug.c
View File

@ -1317,7 +1317,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
list_add_tail(&page->lru, &source); list_add_tail(&page->lru, &source);
if (!__PageMovable(page)) if (!__PageMovable(page))
inc_node_page_state(page, NR_ISOLATED_ANON + inc_node_page_state(page, NR_ISOLATED_ANON +
page_is_file_cache(page)); page_is_file_lru(page));
} else { } else {
pr_warn("failed to isolate pfn %lx\n", pfn); pr_warn("failed to isolate pfn %lx\n", pfn);

2
mm/mempolicy.c
View File

@ -1022,7 +1022,7 @@ static int migrate_page_add(struct page *page, struct list_head *pagelist,
if (!isolate_lru_page(head)) { if (!isolate_lru_page(head)) {
list_add_tail(&head->lru, pagelist); list_add_tail(&head->lru, pagelist);
mod_node_page_state(page_pgdat(head), mod_node_page_state(page_pgdat(head),
NR_ISOLATED_ANON + page_is_file_cache(head), NR_ISOLATED_ANON + page_is_file_lru(head),
hpage_nr_pages(head)); hpage_nr_pages(head));
} else if (flags & MPOL_MF_STRICT) { } else if (flags & MPOL_MF_STRICT) {
/* /*

16
mm/migrate.c
View File

@ -193,7 +193,7 @@ void putback_movable_pages(struct list_head *l)
put_page(page); put_page(page);
} else { } else {
mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON +
page_is_file_cache(page), -hpage_nr_pages(page)); page_is_file_lru(page), -hpage_nr_pages(page));
putback_lru_page(page); putback_lru_page(page);
} }
} }
@ -1219,7 +1219,7 @@ out:
*/ */
if (likely(!__PageMovable(page))) if (likely(!__PageMovable(page)))
mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON +
page_is_file_cache(page), -hpage_nr_pages(page)); page_is_file_lru(page), -hpage_nr_pages(page));
} }
/* /*
@ -1592,7 +1592,7 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr,
err = 1; err = 1;
list_add_tail(&head->lru, pagelist); list_add_tail(&head->lru, pagelist);
mod_node_page_state(page_pgdat(head), mod_node_page_state(page_pgdat(head),
NR_ISOLATED_ANON + page_is_file_cache(head), NR_ISOLATED_ANON + page_is_file_lru(head),
hpage_nr_pages(head)); hpage_nr_pages(head));
} }
out_putpage: out_putpage:
@ -1955,7 +1955,7 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page)
return 0; return 0;
} }
page_lru = page_is_file_cache(page); page_lru = page_is_file_lru(page);
mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + page_lru, mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + page_lru,
hpage_nr_pages(page)); hpage_nr_pages(page));
@ -1991,7 +1991,7 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
* Don't migrate file pages that are mapped in multiple processes * Don't migrate file pages that are mapped in multiple processes
* with execute permissions as they are probably shared libraries. * with execute permissions as they are probably shared libraries.
*/ */
if (page_mapcount(page) != 1 && page_is_file_cache(page) && if (page_mapcount(page) != 1 && page_is_file_lru(page) &&
(vma->vm_flags & VM_EXEC)) (vma->vm_flags & VM_EXEC))
goto out; goto out;
@ -1999,7 +1999,7 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
* Also do not migrate dirty pages as not all filesystems can move * Also do not migrate dirty pages as not all filesystems can move
* dirty pages in MIGRATE_ASYNC mode which is a waste of cycles. * dirty pages in MIGRATE_ASYNC mode which is a waste of cycles.
*/ */
if (page_is_file_cache(page) && PageDirty(page)) if (page_is_file_lru(page) && PageDirty(page))
goto out; goto out;
isolated = numamigrate_isolate_page(pgdat, page); isolated = numamigrate_isolate_page(pgdat, page);
@ -2014,7 +2014,7 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
if (!list_empty(&migratepages)) { if (!list_empty(&migratepages)) {
list_del(&page->lru); list_del(&page->lru);
dec_node_page_state(page, NR_ISOLATED_ANON + dec_node_page_state(page, NR_ISOLATED_ANON +
page_is_file_cache(page)); page_is_file_lru(page));
putback_lru_page(page); putback_lru_page(page);
} }
isolated = 0; isolated = 0;
@ -2044,7 +2044,7 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
pg_data_t *pgdat = NODE_DATA(node); pg_data_t *pgdat = NODE_DATA(node);
int isolated = 0; int isolated = 0;
struct page *new_page = NULL; struct page *new_page = NULL;
int page_lru = page_is_file_cache(page); int page_lru = page_is_file_lru(page);
unsigned long start = address & HPAGE_PMD_MASK; unsigned long start = address & HPAGE_PMD_MASK;
new_page = alloc_pages_node(node, new_page = alloc_pages_node(node,

2
mm/mprotect.c
View File

@ -98,7 +98,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
* it cannot move them all from MIGRATE_ASYNC * it cannot move them all from MIGRATE_ASYNC
* context. * context.
*/ */
if (page_is_file_cache(page) && PageDirty(page)) if (page_is_file_lru(page) && PageDirty(page))
continue; continue;
/* /*

16
mm/swap.c
View File

@ -276,7 +276,7 @@ static void __activate_page(struct page *page, struct lruvec *lruvec,
void *arg) void *arg)
{ {
if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
int file = page_is_file_cache(page); int file = page_is_file_lru(page);
int lru = page_lru_base_type(page); int lru = page_lru_base_type(page);
del_page_from_lru_list(page, lruvec, lru); del_page_from_lru_list(page, lruvec, lru);
@ -394,7 +394,7 @@ void mark_page_accessed(struct page *page)
else else
__lru_cache_activate_page(page); __lru_cache_activate_page(page);
ClearPageReferenced(page); ClearPageReferenced(page);
if (page_is_file_cache(page)) if (page_is_file_lru(page))
workingset_activation(page); workingset_activation(page);
} }
if (page_is_idle(page)) if (page_is_idle(page))
@ -515,7 +515,7 @@ static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec,
return; return;
active = PageActive(page); active = PageActive(page);
file = page_is_file_cache(page); file = page_is_file_lru(page);
lru = page_lru_base_type(page); lru = page_lru_base_type(page);
del_page_from_lru_list(page, lruvec, lru + active); del_page_from_lru_list(page, lruvec, lru + active);
@ -548,7 +548,7 @@ static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec,
void *arg) void *arg)
{ {
if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) { if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) {
int file = page_is_file_cache(page); int file = page_is_file_lru(page);
int lru = page_lru_base_type(page); int lru = page_lru_base_type(page);
del_page_from_lru_list(page, lruvec, lru + LRU_ACTIVE); del_page_from_lru_list(page, lruvec, lru + LRU_ACTIVE);
@ -573,9 +573,9 @@ static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec,
ClearPageActive(page); ClearPageActive(page);
ClearPageReferenced(page); ClearPageReferenced(page);
/* /*
* lazyfree pages are clean anonymous pages. They have * Lazyfree pages are clean anonymous pages. They have
* SwapBacked flag cleared to distinguish normal anonymous * PG_swapbacked flag cleared, to distinguish them from normal
* pages * anonymous pages
*/ */
ClearPageSwapBacked(page); ClearPageSwapBacked(page);
add_page_to_lru_list(page, lruvec, LRU_INACTIVE_FILE); add_page_to_lru_list(page, lruvec, LRU_INACTIVE_FILE);
@ -962,7 +962,7 @@ static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec,
if (page_evictable(page)) { if (page_evictable(page)) {
lru = page_lru(page); lru = page_lru(page);
update_page_reclaim_stat(lruvec, page_is_file_cache(page), update_page_reclaim_stat(lruvec, page_is_file_lru(page),
PageActive(page)); PageActive(page));
if (was_unevictable) if (was_unevictable)
count_vm_event(UNEVICTABLE_PGRESCUED); count_vm_event(UNEVICTABLE_PGRESCUED);

12
mm/vmscan.c
View File

@ -919,7 +919,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
* exceptional entries and shadow exceptional entries in the * exceptional entries and shadow exceptional entries in the
* same address_space. * same address_space.
*/ */
if (reclaimed && page_is_file_cache(page) && if (reclaimed && page_is_file_lru(page) &&
!mapping_exiting(mapping) && !dax_mapping(mapping)) !mapping_exiting(mapping) && !dax_mapping(mapping))
shadow = workingset_eviction(page, target_memcg); shadow = workingset_eviction(page, target_memcg);
__delete_from_page_cache(page, shadow); __delete_from_page_cache(page, shadow);
@ -1043,7 +1043,7 @@ static void page_check_dirty_writeback(struct page *page,
* Anonymous pages are not handled by flushers and must be written * Anonymous pages are not handled by flushers and must be written
* from reclaim context. Do not stall reclaim based on them * from reclaim context. Do not stall reclaim based on them
*/ */
if (!page_is_file_cache(page) || if (!page_is_file_lru(page) ||
(PageAnon(page) && !PageSwapBacked(page))) { (PageAnon(page) && !PageSwapBacked(page))) {
*dirty = false; *dirty = false;
*writeback = false; *writeback = false;
@ -1315,7 +1315,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
* the rest of the LRU for clean pages and see * the rest of the LRU for clean pages and see
* the same dirty pages again (PageReclaim). * the same dirty pages again (PageReclaim).
*/ */
if (page_is_file_cache(page) && if (page_is_file_lru(page) &&
(!current_is_kswapd() || !PageReclaim(page) || (!current_is_kswapd() || !PageReclaim(page) ||
!test_bit(PGDAT_DIRTY, &pgdat->flags))) { !test_bit(PGDAT_DIRTY, &pgdat->flags))) {
/* /*
@ -1459,7 +1459,7 @@ activate_locked:
try_to_free_swap(page); try_to_free_swap(page);
VM_BUG_ON_PAGE(PageActive(page), page); VM_BUG_ON_PAGE(PageActive(page), page);
if (!PageMlocked(page)) { if (!PageMlocked(page)) {
int type = page_is_file_cache(page); int type = page_is_file_lru(page);
SetPageActive(page); SetPageActive(page);
stat->nr_activate[type] += nr_pages; stat->nr_activate[type] += nr_pages;
count_memcg_page_event(page, PGACTIVATE); count_memcg_page_event(page, PGACTIVATE);
@ -1497,7 +1497,7 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
LIST_HEAD(clean_pages); LIST_HEAD(clean_pages);
list_for_each_entry_safe(page, next, page_list, lru) { list_for_each_entry_safe(page, next, page_list, lru) {
if (page_is_file_cache(page) && !PageDirty(page) && if (page_is_file_lru(page) && !PageDirty(page) &&
!__PageMovable(page) && !PageUnevictable(page)) { !__PageMovable(page) && !PageUnevictable(page)) {
ClearPageActive(page); ClearPageActive(page);
list_move(&page->lru, &clean_pages); list_move(&page->lru, &clean_pages);
@ -2053,7 +2053,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
* IO, plus JVM can create lots of anon VM_EXEC pages, * IO, plus JVM can create lots of anon VM_EXEC pages,
* so we ignore them here. * so we ignore them here.
*/ */
if ((vm_flags & VM_EXEC) && page_is_file_cache(page)) { if ((vm_flags & VM_EXEC) && page_is_file_lru(page)) {
list_add(&page->lru, &l_active); list_add(&page->lru, &l_active);
continue; continue;
} }