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mm: move MADV_FREE pages into LRU_INACTIVE_FILE list
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madv()'s MADV_FREE indicate pages are 'lazyfree'.  They are still
anonymous pages, but they can be freed without pageout.  To distinguish
these from normal anonymous pages, we clear their SwapBacked flag.

MADV_FREE pages could be freed without pageout, so they pretty much like
used once file pages.  For such pages, we'd like to reclaim them once
there is memory pressure.  Also it might be unfair reclaiming MADV_FREE
pages always before used once file pages and we definitively want to
reclaim the pages before other anonymous and file pages.

To speed up MADV_FREE pages reclaim, we put the pages into
LRU_INACTIVE_FILE list.  The rationale is LRU_INACTIVE_FILE list is tiny
nowadays and should be full of used once file pages.  Reclaiming
MADV_FREE pages will not have much interfere of anonymous and active
file pages.  And the inactive file pages and MADV_FREE pages will be
reclaimed according to their age, so we don't reclaim too many MADV_FREE
pages too.  Putting the MADV_FREE pages into LRU_INACTIVE_FILE_LIST also
means we can reclaim the pages without swap support.  This idea is
suggested by Johannes.

This patch doesn't move MADV_FREE pages to LRU_INACTIVE_FILE list yet to
avoid bisect failure, next patch will do it.

The patch is based on Minchan's original patch.

[[email protected]: coding-style fixes]
Link: http://lkml.kernel.org/r/2f87063c1e9354677b7618c647abde77b07561e5.1487965799.git.shli@fb.com
Signed-off-by: Shaohua Li <[email protected]>
Suggested-by: Johannes Weiner <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Acked-by: Minchan Kim <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: Hillf Danton <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Mel Gorman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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shligit authored and torvalds committed May 3, 2017
1 parent d44d363 commit f7ad2a6
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Showing 6 changed files with 31 additions and 28 deletions.
2 changes: 1 addition & 1 deletion include/linux/swap.h
Original file line number Diff line number Diff line change
Expand Up @@ -279,7 +279,7 @@ extern void lru_add_drain_cpu(int cpu);
extern void lru_add_drain_all(void);
extern void rotate_reclaimable_page(struct page *page);
extern void deactivate_file_page(struct page *page);
extern void deactivate_page(struct page *page);
extern void mark_page_lazyfree(struct page *page);
extern void swap_setup(void);

extern void add_page_to_unevictable_list(struct page *page);
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2 changes: 1 addition & 1 deletion include/linux/vm_event_item.h
Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
FOR_ALL_ZONES(PGALLOC),
FOR_ALL_ZONES(ALLOCSTALL),
FOR_ALL_ZONES(PGSCAN_SKIP),
PGFREE, PGACTIVATE, PGDEACTIVATE,
PGFREE, PGACTIVATE, PGDEACTIVATE, PGLAZYFREE,
PGFAULT, PGMAJFAULT,
PGLAZYFREED,
PGREFILL,
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3 changes: 0 additions & 3 deletions mm/huge_memory.c
Original file line number Diff line number Diff line change
Expand Up @@ -1564,9 +1564,6 @@ bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
ClearPageDirty(page);
unlock_page(page);

if (PageActive(page))
deactivate_page(page);

if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) {
pmdp_invalidate(vma, addr, pmd);
orig_pmd = pmd_mkold(orig_pmd);
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2 changes: 0 additions & 2 deletions mm/madvise.c
Original file line number Diff line number Diff line change
Expand Up @@ -411,8 +411,6 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
ptent = pte_mkold(ptent);
ptent = pte_mkclean(ptent);
set_pte_at(mm, addr, pte, ptent);
if (PageActive(page))
deactivate_page(page);
tlb_remove_tlb_entry(tlb, pte, addr);
}
}
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49 changes: 28 additions & 21 deletions mm/swap.c
Original file line number Diff line number Diff line change
Expand Up @@ -46,7 +46,7 @@ int page_cluster;
static DEFINE_PER_CPU(struct pagevec, lru_add_pvec);
static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs);
static DEFINE_PER_CPU(struct pagevec, lru_deactivate_file_pvecs);
static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs);
static DEFINE_PER_CPU(struct pagevec, lru_lazyfree_pvecs);
#ifdef CONFIG_SMP
static DEFINE_PER_CPU(struct pagevec, activate_page_pvecs);
#endif
Expand Down Expand Up @@ -571,20 +571,27 @@ static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec,
}


static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec,
static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec,
void *arg)
{
if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) {
int file = page_is_file_cache(page);
int lru = page_lru_base_type(page);
if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) &&
!PageUnevictable(page)) {
bool active = PageActive(page);

del_page_from_lru_list(page, lruvec, lru + LRU_ACTIVE);
del_page_from_lru_list(page, lruvec,
LRU_INACTIVE_ANON + active);
ClearPageActive(page);
ClearPageReferenced(page);
add_page_to_lru_list(page, lruvec, lru);
/*
* lazyfree pages are clean anonymous pages. They have
* SwapBacked flag cleared to distinguish normal anonymous
* pages
*/
ClearPageSwapBacked(page);
add_page_to_lru_list(page, lruvec, LRU_INACTIVE_FILE);

__count_vm_event(PGDEACTIVATE);
update_page_reclaim_stat(lruvec, file, 0);
__count_vm_events(PGLAZYFREE, hpage_nr_pages(page));
update_page_reclaim_stat(lruvec, 1, 0);
}
}

Expand Down Expand Up @@ -614,9 +621,9 @@ void lru_add_drain_cpu(int cpu)
if (pagevec_count(pvec))
pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, NULL);

pvec = &per_cpu(lru_deactivate_pvecs, cpu);
pvec = &per_cpu(lru_lazyfree_pvecs, cpu);
if (pagevec_count(pvec))
pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
pagevec_lru_move_fn(pvec, lru_lazyfree_fn, NULL);

activate_page_drain(cpu);
}
Expand Down Expand Up @@ -648,22 +655,22 @@ void deactivate_file_page(struct page *page)
}

/**
* deactivate_page - deactivate a page
* mark_page_lazyfree - make an anon page lazyfree
* @page: page to deactivate
*
* deactivate_page() moves @page to the inactive list if @page was on the active
* list and was not an unevictable page. This is done to accelerate the reclaim
* of @page.
* mark_page_lazyfree() moves @page to the inactive file list.
* This is done to accelerate the reclaim of @page.
*/
void deactivate_page(struct page *page)
void mark_page_lazyfree(struct page *page)
{
if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) {
struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs);
if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) &&
!PageUnevictable(page)) {
struct pagevec *pvec = &get_cpu_var(lru_lazyfree_pvecs);

get_page(page);
if (!pagevec_add(pvec, page) || PageCompound(page))
pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
put_cpu_var(lru_deactivate_pvecs);
pagevec_lru_move_fn(pvec, lru_lazyfree_fn, NULL);
put_cpu_var(lru_lazyfree_pvecs);
}
}

Expand Down Expand Up @@ -703,7 +710,7 @@ void lru_add_drain_all(void)
if (pagevec_count(&per_cpu(lru_add_pvec, cpu)) ||
pagevec_count(&per_cpu(lru_rotate_pvecs, cpu)) ||
pagevec_count(&per_cpu(lru_deactivate_file_pvecs, cpu)) ||
pagevec_count(&per_cpu(lru_deactivate_pvecs, cpu)) ||
pagevec_count(&per_cpu(lru_lazyfree_pvecs, cpu)) ||
need_activate_page_drain(cpu)) {
INIT_WORK(work, lru_add_drain_per_cpu);
queue_work_on(cpu, mm_percpu_wq, work);
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1 change: 1 addition & 0 deletions mm/vmstat.c
Original file line number Diff line number Diff line change
Expand Up @@ -991,6 +991,7 @@ const char * const vmstat_text[] = {
"pgfree",
"pgactivate",
"pgdeactivate",
"pglazyfree",

"pgfault",
"pgmajfault",
Expand Down

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