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Message-ID: <20240320074049.4130552-10-alexs@kernel.org>
Date: Wed, 20 Mar 2024 15:40:45 +0800
From: alexs@...nel.org
To: Izik Eidus <izik.eidus@...ellosystems.com>,
Matthew Wilcox <willy@...radead.org>,
Andrea Arcangeli <aarcange@...hat.com>,
Hugh Dickins <hughd@...gle.com>,
Chris Wright <chrisw@...s-sol.org>,
kasong@...cent.com,
Andrew Morton <akpm@...ux-foundation.org>,
linux-mm@...ck.org (open list:MEMORY MANAGEMENT),
linux-kernel@...r.kernel.org (open list)
Cc: linux-kernel@...r.kernel.org,
"Alex Shi (tencent)" <alexs@...nel.org>
Subject: [PATCH 09/11] mm/ksm: Convert stable_tree_search to use folio
From: "Alex Shi (tencent)" <alexs@...nel.org>
Although, the func may pass a tail page to check its contents, but only
single page exist in KSM stable tree, so we still can use folio in
stable_tree_search() to save a few compound_head calls.
Signed-off-by: Alex Shi (tencent) <alexs@...nel.org>
Cc: Izik Eidus <izik.eidus@...ellosystems.com>
Cc: Matthew Wilcox <willy@...radead.org>
Cc: Andrea Arcangeli <aarcange@...hat.com>
Cc: Hugh Dickins <hughd@...gle.com>
Cc: Chris Wright <chrisw@...s-sol.org>
---
mm/ksm.c | 60 +++++++++++++++++++++++++++++---------------------------
1 file changed, 31 insertions(+), 29 deletions(-)
diff --git a/mm/ksm.c b/mm/ksm.c
index 71d1a52f344d..75401b3bae5c 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1812,7 +1812,7 @@ static __always_inline void *chain(struct ksm_stable_node **s_n_d,
* This function returns the stable tree node of identical content if found,
* NULL otherwise.
*/
-static struct page *stable_tree_search(struct page *page)
+static void *stable_tree_search(struct page *page)
{
int nid;
struct rb_root *root;
@@ -1820,28 +1820,30 @@ static struct page *stable_tree_search(struct page *page)
struct rb_node *parent;
struct ksm_stable_node *stable_node, *stable_node_dup, *stable_node_any;
struct ksm_stable_node *page_node;
+ struct folio *folio;
- page_node = page_stable_node(page);
+ folio = (struct folio *)page;
+ page_node = folio_stable_node(folio);
if (page_node && page_node->head != &migrate_nodes) {
/* ksm page forked */
- get_page(page);
- return page;
+ folio_get(folio);
+ return folio;
}
- nid = get_kpfn_nid(page_to_pfn(page));
+ nid = get_kpfn_nid(folio_pfn(folio));
root = root_stable_tree + nid;
again:
new = &root->rb_node;
parent = NULL;
while (*new) {
- struct page *tree_page;
+ struct folio *tree_folio;
int ret;
cond_resched();
stable_node = rb_entry(*new, struct ksm_stable_node, node);
stable_node_any = NULL;
- tree_page = chain_prune(&stable_node_dup, &stable_node, root);
+ tree_folio = chain_prune(&stable_node_dup, &stable_node, root);
/*
* NOTE: stable_node may have been freed by
* chain_prune() if the returned stable_node_dup is
@@ -1875,11 +1877,11 @@ static struct page *stable_tree_search(struct page *page)
* write protected at all times. Any will work
* fine to continue the walk.
*/
- tree_page = get_ksm_page(stable_node_any,
- GET_KSM_PAGE_NOLOCK);
+ tree_folio = get_ksm_page(stable_node_any,
+ GET_KSM_PAGE_NOLOCK);
}
VM_BUG_ON(!stable_node_dup ^ !!stable_node_any);
- if (!tree_page) {
+ if (!tree_folio) {
/*
* If we walked over a stale stable_node,
* get_ksm_page() will call rb_erase() and it
@@ -1892,8 +1894,8 @@ static struct page *stable_tree_search(struct page *page)
goto again;
}
- ret = memcmp_pages(page, tree_page);
- put_page(tree_page);
+ ret = memcmp_pages(&folio->page, &tree_folio->page);
+ folio_put(tree_folio);
parent = *new;
if (ret < 0)
@@ -1936,26 +1938,26 @@ static struct page *stable_tree_search(struct page *page)
* It would be more elegant to return stable_node
* than kpage, but that involves more changes.
*/
- tree_page = get_ksm_page(stable_node_dup,
- GET_KSM_PAGE_TRYLOCK);
+ tree_folio = get_ksm_page(stable_node_dup,
+ GET_KSM_PAGE_TRYLOCK);
- if (PTR_ERR(tree_page) == -EBUSY)
+ if (PTR_ERR(tree_folio) == -EBUSY)
return ERR_PTR(-EBUSY);
- if (unlikely(!tree_page))
+ if (unlikely(!tree_folio))
/*
* The tree may have been rebalanced,
* so re-evaluate parent and new.
*/
goto again;
- unlock_page(tree_page);
+ folio_unlock(tree_folio);
if (get_kpfn_nid(stable_node_dup->kpfn) !=
NUMA(stable_node_dup->nid)) {
- put_page(tree_page);
+ folio_put(tree_folio);
goto replace;
}
- return tree_page;
+ return tree_folio;
}
}
@@ -1968,8 +1970,8 @@ static struct page *stable_tree_search(struct page *page)
rb_insert_color(&page_node->node, root);
out:
if (is_page_sharing_candidate(page_node)) {
- get_page(page);
- return page;
+ folio_get(folio);
+ return folio;
} else
return NULL;
@@ -1994,12 +1996,12 @@ static struct page *stable_tree_search(struct page *page)
&page_node->node,
root);
if (is_page_sharing_candidate(page_node))
- get_page(page);
+ folio_get(folio);
else
- page = NULL;
+ folio = NULL;
} else {
rb_erase(&stable_node_dup->node, root);
- page = NULL;
+ folio = NULL;
}
} else {
VM_BUG_ON(!is_stable_node_chain(stable_node));
@@ -2010,16 +2012,16 @@ static struct page *stable_tree_search(struct page *page)
DO_NUMA(page_node->nid = nid);
stable_node_chain_add_dup(page_node, stable_node);
if (is_page_sharing_candidate(page_node))
- get_page(page);
+ folio_get(folio);
else
- page = NULL;
+ folio = NULL;
} else {
- page = NULL;
+ folio = NULL;
}
}
stable_node_dup->head = &migrate_nodes;
list_add(&stable_node_dup->list, stable_node_dup->head);
- return page;
+ return folio;
chain_append:
/* stable_node_dup could be null if it reached the limit */
@@ -2109,7 +2111,7 @@ static struct ksm_stable_node *stable_tree_insert(struct folio *kfolio)
* fine to continue the walk.
*/
tree_folio = get_ksm_page(stable_node_any,
- GET_KSM_PAGE_NOLOCK);
+ GET_KSM_PAGE_NOLOCK);
}
VM_BUG_ON(!stable_node_dup ^ !!stable_node_any);
if (!tree_folio) {
--
2.43.0
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