github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-06-05 13:06:59 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

mm/khugepaged: minor reorderings in collapse_shmem()

Browse Source 
commit 042a308248 upstream.

Several cleanups in collapse_shmem(): most of which probably do not
really matter, beyond doing things in a more familiar and reassuring
order.  Simplify the failure gotos in the main loop, and on success
update stats while interrupts still disabled from the last iteration.

Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261526400.2275@eggly.anvils
Fixes: f3f0e1d215 ("khugepaged: add support of collapse for tmpfs/shmem pages")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>	[4.8+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Hugh Dickins 2018-11-30 14:10:39 -08:00 committed by Greg Kroah-Hartman
parent ee13d69bc1
commit 3e9646c76c
1 changed files with 30 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

73
mm/khugepaged.c
View File

@ -1330,13 +1330,12 @@ static void collapse_shmem(struct mm_struct *mm,
goto out;
}
__SetPageLocked(new_page);
__SetPageSwapBacked(new_page);
new_page->index = start;
new_page->mapping = mapping;
__SetPageSwapBacked(new_page);
__SetPageLocked(new_page);
BUG_ON(!page_ref_freeze(new_page, 1));
/*
* At this point the new_page is 'frozen' (page_count() is zero), locked
* and not up-to-date. It's safe to insert it into radix tree, because
@ -1365,13 +1364,13 @@ static void collapse_shmem(struct mm_struct *mm,
*/
if (n && !shmem_charge(mapping->host, n)) {
result = SCAN_FAIL;
break;
goto tree_locked;
}
nr_none += n;
for (; index < min(iter.index, end); index++) {
radix_tree_insert(&mapping->i_pages, index,
new_page + (index % HPAGE_PMD_NR));
}
nr_none += n;
/* We are done. */
if (index >= end)
@ -1387,12 +1386,12 @@ static void collapse_shmem(struct mm_struct *mm,
result = SCAN_FAIL;
goto tree_unlocked;
}
xa_lock_irq(&mapping->i_pages);
} else if (trylock_page(page)) {
get_page(page);
xa_unlock_irq(&mapping->i_pages);
} else {
result = SCAN_PAGE_LOCK;
break;
goto tree_locked;
}
/*
@ -1407,11 +1406,10 @@ static void collapse_shmem(struct mm_struct *mm,
result = SCAN_TRUNCATED;
goto out_unlock;
}
xa_unlock_irq(&mapping->i_pages);
if (isolate_lru_page(page)) {
result = SCAN_DEL_PAGE_LRU;
goto out_isolate_failed;
goto out_unlock;
}
if (page_mapped(page))
@ -1432,7 +1430,9 @@ static void collapse_shmem(struct mm_struct *mm,
*/
if (!page_ref_freeze(page, 3)) {
result = SCAN_PAGE_COUNT;
goto out_lru;
xa_unlock_irq(&mapping->i_pages);
putback_lru_page(page);
goto out_unlock;
}
/*
@ -1448,17 +1448,10 @@ static void collapse_shmem(struct mm_struct *mm,
slot = radix_tree_iter_resume(slot, &iter);
index++;
continue;
out_lru:
xa_unlock_irq(&mapping->i_pages);
putback_lru_page(page);
out_isolate_failed:
unlock_page(page);
put_page(page);
goto tree_unlocked;
out_unlock:
unlock_page(page);
put_page(page);
break;
goto tree_unlocked;
}
/*
@ -1466,7 +1459,7 @@ static void collapse_shmem(struct mm_struct *mm,
* This code only triggers if there's nothing in radix tree
* beyond 'end'.
*/
if (result == SCAN_SUCCEED && index < end) {
if (index < end) {
int n = end - index;
/* Stop if extent has been truncated, and is now empty */
@ -1478,7 +1471,6 @@ static void collapse_shmem(struct mm_struct *mm,
result = SCAN_FAIL;
goto tree_locked;
}
for (; index < end; index++) {
radix_tree_insert(&mapping->i_pages, index,
new_page + (index % HPAGE_PMD_NR));
@ -1486,14 +1478,19 @@ static void collapse_shmem(struct mm_struct *mm,
nr_none += n;
}
__inc_node_page_state(new_page, NR_SHMEM_THPS);
if (nr_none) {
struct zone *zone = page_zone(new_page);
__mod_node_page_state(zone->zone_pgdat, NR_FILE_PAGES, nr_none);
__mod_node_page_state(zone->zone_pgdat, NR_SHMEM, nr_none);
}
tree_locked:
xa_unlock_irq(&mapping->i_pages);
tree_unlocked:
if (result == SCAN_SUCCEED) {
unsigned long flags;
struct zone *zone = page_zone(new_page);
/*
* Replacing old pages with new one has succeed, now we need to
* copy the content and free old pages.
@ -1507,11 +1504,11 @@ static void collapse_shmem(struct mm_struct *mm,
copy_highpage(new_page + (page->index % HPAGE_PMD_NR),
page);
list_del(&page->lru);
unlock_page(page);
page_ref_unfreeze(page, 1);
page->mapping = NULL;
page_ref_unfreeze(page, 1);
ClearPageActive(page);
ClearPageUnevictable(page);
unlock_page(page);
put_page(page);
index++;
}
@ -1520,28 +1517,17 @@ static void collapse_shmem(struct mm_struct *mm,
index++;
}
local_irq_save(flags);
__inc_node_page_state(new_page, NR_SHMEM_THPS);
if (nr_none) {
__mod_node_page_state(zone->zone_pgdat, NR_FILE_PAGES, nr_none);
__mod_node_page_state(zone->zone_pgdat, NR_SHMEM, nr_none);
}
local_irq_restore(flags);
/*
* Remove pte page tables, so we can re-faulti
* the page as huge.
*/
retract_page_tables(mapping, start);
/* Everything is ready, let's unfreeze the new_page */
set_page_dirty(new_page);
SetPageUptodate(new_page);
page_ref_unfreeze(new_page, HPAGE_PMD_NR);
set_page_dirty(new_page);
mem_cgroup_commit_charge(new_page, memcg, false, true);
lru_cache_add_anon(new_page);
unlock_page(new_page);
/*
* Remove pte page tables, so we can re-fault the page as huge.
*/
retract_page_tables(mapping, start);
*hpage = NULL;
khugepaged_pages_collapsed++;
@ -1573,8 +1559,8 @@ static void collapse_shmem(struct mm_struct *mm,
radix_tree_replace_slot(&mapping->i_pages, slot, page);
slot = radix_tree_iter_resume(slot, &iter);
xa_unlock_irq(&mapping->i_pages);
putback_lru_page(page);
unlock_page(page);
putback_lru_page(page);
xa_lock_irq(&mapping->i_pages);
}
VM_BUG_ON(nr_none);
@ -1583,9 +1569,10 @@ static void collapse_shmem(struct mm_struct *mm,
/* Unfreeze new_page, caller would take care about freeing it */
page_ref_unfreeze(new_page, 1);
mem_cgroup_cancel_charge(new_page, memcg, true);
unlock_page(new_page);
new_page->mapping = NULL;
}
unlock_page(new_page);
out:
VM_BUG_ON(!list_empty(&pagelist));
/* TODO: tracepoints */