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memcg: convert mem_cgroup_move_charge_pte_range() to use a folio 

Patch series "Convert memcontrol charge moving to use folios".

No part of these patches should change behaviour; all the called functions
already convert from page to folio, so this ought to simply be a reduction
in the number of calls to compound_head().  


This patch (of 4):

Remove many calls to compound_head() by calling page_folio() once at the
start of each stanza which receives a struct page from 'target'.  There
should be no change in behaviour here as all the called functions start
out by converting the page to its folio.

Link: https://lkml.kernel.org/r/20240111181219.3462852-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20240111181219.3462852-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2024-01-11 18:12:16 +00:00 committed by Andrew Morton
parent 05976a42b3
commit b267e1a3e4
1 changed files with 24 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

49
mm/memcontrol.c
View File

@ -5965,23 +5965,22 @@ static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
}
/**
* mem_cgroup_move_account - move account of the page
* @page: the page
* mem_cgroup_move_account - move account of the folio
* @folio: The folio.
* @compound: charge the page as compound or small page
* @from: mem_cgroup which the page is moved from.
* @to: mem_cgroup which the page is moved to. @from != @to.
* @from: mem_cgroup which the folio is moved from.
* @to: mem_cgroup which the folio is moved to. @from != @to.
*
* The page must be locked and not on the LRU.
* The folio must be locked and not on the LRU.
*
* This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
* from old cgroup.
*/
static int mem_cgroup_move_account(struct page *page,
static int mem_cgroup_move_account(struct folio *folio,
bool compound,
struct mem_cgroup *from,
struct mem_cgroup *to)
{
struct folio *folio = page_folio(page);
struct lruvec *from_vec, *to_vec;
struct pglist_data *pgdat;
unsigned int nr_pages = compound ? folio_nr_pages(folio) : 1;
@ -6431,7 +6430,7 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
spinlock_t *ptl;
enum mc_target_type target_type;
union mc_target target;
struct page *page;
struct folio *folio;
ptl = pmd_trans_huge_lock(pmd, vma);
if (ptl) {
@ -6441,26 +6440,26 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
}
target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
if (target_type == MC_TARGET_PAGE) {
page = target.page;
if (isolate_lru_page(page)) {
if (!mem_cgroup_move_account(page, true,
folio = page_folio(target.page);
if (folio_isolate_lru(folio)) {
if (!mem_cgroup_move_account(folio, true,
mc.from, mc.to)) {
mc.precharge -= HPAGE_PMD_NR;
mc.moved_charge += HPAGE_PMD_NR;
}
putback_lru_page(page);
folio_putback_lru(folio);
}
unlock_page(page);
put_page(page);
folio_unlock(folio);
folio_put(folio);
} else if (target_type == MC_TARGET_DEVICE) {
page = target.page;
if (!mem_cgroup_move_account(page, true,
folio = page_folio(target.page);
if (!mem_cgroup_move_account(folio, true,
mc.from, mc.to)) {
mc.precharge -= HPAGE_PMD_NR;
mc.moved_charge += HPAGE_PMD_NR;
}
unlock_page(page);
put_page(page);
folio_unlock(folio);
folio_put(folio);
}
spin_unlock(ptl);
return 0;
@ -6483,28 +6482,28 @@ retry:
device = true;
fallthrough;
case MC_TARGET_PAGE:
page = target.page;
folio = page_folio(target.page);
/*
* We can have a part of the split pmd here. Moving it
* can be done but it would be too convoluted so simply
* ignore such a partial THP and keep it in original
* memcg. There should be somebody mapping the head.
*/
if (PageTransCompound(page))
if (folio_test_large(folio))
goto put;
if (!device && !isolate_lru_page(page))
if (!device && !folio_isolate_lru(folio))
goto put;
if (!mem_cgroup_move_account(page, false,
if (!mem_cgroup_move_account(folio, false,
mc.from, mc.to)) {
mc.precharge--;
/* we uncharge from mc.from later. */
mc.moved_charge++;
}
if (!device)
putback_lru_page(page);
folio_putback_lru(folio);
put: /* get_mctgt_type() gets & locks the page */
unlock_page(page);
put_page(page);
folio_unlock(folio);
folio_put(folio);
break;
case MC_TARGET_SWAP:
ent = target.ent;