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Message-ID: <20251026203611.1608903-4-surenb@google.com>
Date: Sun, 26 Oct 2025 13:36:06 -0700
From: Suren Baghdasaryan <surenb@...gle.com>
To: akpm@...ux-foundation.org
Cc: david@...hat.com, lorenzo.stoakes@...cle.com, Liam.Howlett@...cle.com,
vbabka@...e.cz, alexandru.elisei@....com, peterx@...hat.com, sj@...nel.org,
rppt@...nel.org, mhocko@...e.com, corbet@....net, axboe@...nel.dk,
viro@...iv.linux.org.uk, brauner@...nel.org, hch@...radead.org, jack@...e.cz,
willy@...radead.org, m.szyprowski@...sung.com, robin.murphy@....com,
hannes@...xchg.org, zhengqi.arch@...edance.com, shakeel.butt@...ux.dev,
axelrasmussen@...gle.com, yuanchu@...gle.com, weixugc@...gle.com,
minchan@...nel.org, surenb@...gle.com, linux-mm@...ck.org,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-block@...r.kernel.org, linux-fsdevel@...r.kernel.org,
iommu@...ts.linux.dev
Subject: [PATCH v2 3/8] mm/cleancache: readahead support
Restore pages from the cleancache during readahead operation.
Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
---
include/linux/cleancache.h | 13 +++++++++
mm/cleancache.c | 58 ++++++++++++++++++++++++++++++++++++++
mm/readahead.c | 54 +++++++++++++++++++++++++++++++++++
3 files changed, 125 insertions(+)
diff --git a/include/linux/cleancache.h b/include/linux/cleancache.h
index 419faa183aba..75361d1cfe3f 100644
--- a/include/linux/cleancache.h
+++ b/include/linux/cleancache.h
@@ -11,6 +11,7 @@
#define CLEANCACHE_KEY_MAX 6
+struct cleancache_inode;
#ifdef CONFIG_CLEANCACHE
@@ -21,6 +22,11 @@ bool cleancache_store_folio(struct inode *inode, struct folio *folio);
bool cleancache_restore_folio(struct inode *inode, struct folio *folio);
bool cleancache_invalidate_folio(struct inode *inode, struct folio *folio);
bool cleancache_invalidate_inode(struct inode *inode);
+struct cleancache_inode *
+cleancache_start_inode_walk(struct inode *inode, unsigned long count);
+void cleancache_end_inode_walk(struct cleancache_inode *ccinode);
+bool cleancache_restore_from_inode(struct cleancache_inode *ccinode,
+ struct folio *folio);
/*
* Backend API
@@ -50,6 +56,13 @@ static inline bool cleancache_invalidate_folio(struct inode *inode,
{ return false; }
static inline bool cleancache_invalidate_inode(struct inode *inode)
{ return false; }
+static inline struct cleancache_inode *
+cleancache_start_inode_walk(struct inode *inode, unsigned long count)
+ { return NULL; }
+static inline void cleancache_end_inode_walk(struct cleancache_inode *ccinode) {}
+static inline bool cleancache_restore_from_inode(struct cleancache_inode *ccinode,
+ struct folio *folio)
+ { return false; }
static inline int cleancache_backend_register_pool(const char *name)
{ return -EOPNOTSUPP; }
static inline int cleancache_backend_get_folio(int pool_id, struct folio *folio)
diff --git a/mm/cleancache.c b/mm/cleancache.c
index 3acf46c0cdd1..6be86938c8fe 100644
--- a/mm/cleancache.c
+++ b/mm/cleancache.c
@@ -799,6 +799,64 @@ bool cleancache_invalidate_inode(struct inode *inode)
return count > 0;
}
+struct cleancache_inode *
+cleancache_start_inode_walk(struct inode *inode, unsigned long count)
+{
+ struct cleancache_inode *ccinode;
+ struct cleancache_fs *fs;
+ int fs_id;
+
+ if (!inode)
+ return ERR_PTR(-EINVAL);
+
+ fs_id = inode->i_sb->cleancache_id;
+ if (fs_id == CLEANCACHE_ID_INVALID)
+ return ERR_PTR(-EINVAL);
+
+ fs = get_fs(fs_id);
+ if (!fs)
+ return NULL;
+
+ ccinode = find_and_get_inode(fs, inode);
+ if (!ccinode) {
+ put_fs(fs);
+ return NULL;
+ }
+
+ return ccinode;
+}
+
+void cleancache_end_inode_walk(struct cleancache_inode *ccinode)
+{
+ struct cleancache_fs *fs = ccinode->fs;
+
+ put_inode(ccinode);
+ put_fs(fs);
+}
+
+bool cleancache_restore_from_inode(struct cleancache_inode *ccinode,
+ struct folio *folio)
+{
+ struct folio *stored_folio;
+ void *src, *dst;
+ bool ret = false;
+
+ xa_lock(&ccinode->folios);
+ stored_folio = xa_load(&ccinode->folios, folio->index);
+ if (stored_folio) {
+ rotate_lru_folio(stored_folio);
+ src = kmap_local_folio(stored_folio, 0);
+ dst = kmap_local_folio(folio, 0);
+ memcpy(dst, src, PAGE_SIZE);
+ kunmap_local(dst);
+ kunmap_local(src);
+ ret = true;
+ }
+ xa_unlock(&ccinode->folios);
+
+ return ret;
+}
+
/* Backend API */
/*
* Register a new backend and add its folios for cleancache to use.
diff --git a/mm/readahead.c b/mm/readahead.c
index 3a4b5d58eeb6..878cc8dfa48e 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -128,6 +128,7 @@
#include <linux/blk-cgroup.h>
#include <linux/fadvise.h>
#include <linux/sched/mm.h>
+#include <linux/cleancache.h>
#define CREATE_TRACE_POINTS
#include <trace/events/readahead.h>
@@ -146,12 +147,65 @@ file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping)
}
EXPORT_SYMBOL_GPL(file_ra_state_init);
+static inline bool restore_from_cleancache(struct readahead_control *rac)
+{
+ XA_STATE(xas, &rac->mapping->i_pages, rac->_index);
+ struct cleancache_inode *ccinode;
+ struct folio *folio;
+ unsigned long end;
+ bool ret = true;
+
+ int count = readahead_count(rac);
+
+ /* Readahead should not have started yet. */
+ VM_BUG_ON(rac->_batch_count != 0);
+
+ if (!count)
+ return true;
+
+ ccinode = cleancache_start_inode_walk(rac->mapping->host, count);
+ if (!ccinode)
+ return false;
+
+ end = rac->_index + rac->_nr_pages - 1;
+ xas_for_each(&xas, folio, end) {
+ unsigned long nr;
+
+ if (xas_retry(&xas, folio)) {
+ ret = false;
+ break;
+ }
+
+ if (!cleancache_restore_from_inode(ccinode, folio)) {
+ ret = false;
+ break;
+ }
+
+ nr = folio_nr_pages(folio);
+ folio_mark_uptodate(folio);
+ folio_unlock(folio);
+ rac->_index += nr;
+ rac->_nr_pages -= nr;
+ rac->ra->size -= nr;
+ if (rac->ra->async_size >= nr)
+ rac->ra->async_size -= nr;
+ }
+
+ cleancache_end_inode_walk(ccinode);
+
+ return ret;
+}
+
static void read_pages(struct readahead_control *rac)
{
const struct address_space_operations *aops = rac->mapping->a_ops;
struct folio *folio;
struct blk_plug plug;
+ /* Try to read all pages from the cleancache */
+ if (restore_from_cleancache(rac))
+ return;
+
if (!readahead_count(rac))
return;
--
2.51.1.851.g4ebd6896fd-goog
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