diff options
| author | Yosry Ahmed <yosryahmed@google.com> | 2023-06-07 19:51:43 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-06-19 16:19:05 -0700 |
| commit | b9c91c43412f2e07a5287dfe7027acdd8fb0b1ef (patch) | |
| tree | 1dfa30c07b46c1c9e048c89eaf66ba58c18daa1a /mm/zswap.c | |
| parent | 32b6a4a1745a46918f748f6fb7641e588fbec6f2 (diff) | |
mm: zswap: support exclusive loads
Commit 71024cb4a0bf ("frontswap: remove frontswap_tmem_exclusive_gets")
removed support for exclusive loads from frontswap as it was not used.
Bring back exclusive loads support to frontswap by adding an "exclusive"
output parameter to frontswap_ops->load.
On the zswap side, add a module parameter to enable/disable exclusive
loads, and a config option to control the boot default value. Refactor
zswap entry invalidation in zswap_frontswap_invalidate_page() into
zswap_invalidate_entry() to reuse it in zswap_frontswap_load() if
exclusive loads are enabled.
With exclusive loads, we avoid having two copies of the same page in
memory (compressed & uncompressed) after faulting it in from zswap. On
the other hand, if the page is to be reclaimed again without being
dirtied, it will be re-compressed. Compression is not usually slow, and a
page that was just faulted in is less likely to be reclaimed again soon.
Link: https://lkml.kernel.org/r/20230607195143.1473802-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Suggested-by: Yu Zhao <yuzhao@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/zswap.c')
| -rw-r--r-- | mm/zswap.c | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/mm/zswap.c b/mm/zswap.c index bcb82e09eb64..9fa86265f6dd 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -138,6 +138,10 @@ static bool zswap_non_same_filled_pages_enabled = true; module_param_named(non_same_filled_pages_enabled, zswap_non_same_filled_pages_enabled, bool, 0644); +static bool zswap_exclusive_loads_enabled = IS_ENABLED( + CONFIG_ZSWAP_EXCLUSIVE_LOADS_DEFAULT_ON); +module_param_named(exclusive_loads, zswap_exclusive_loads_enabled, bool, 0644); + /********************************* * data structures **********************************/ @@ -1340,12 +1344,22 @@ shrink: goto reject; } +static void zswap_invalidate_entry(struct zswap_tree *tree, + struct zswap_entry *entry) +{ + /* remove from rbtree */ + zswap_rb_erase(&tree->rbroot, entry); + + /* drop the initial reference from entry creation */ + zswap_entry_put(tree, entry); +} + /* * returns 0 if the page was successfully decompressed * return -1 on entry not found or error */ static int zswap_frontswap_load(unsigned type, pgoff_t offset, - struct page *page) + struct page *page, bool *exclusive) { struct zswap_tree *tree = zswap_trees[type]; struct zswap_entry *entry; @@ -1415,6 +1429,10 @@ stats: freeentry: spin_lock(&tree->lock); zswap_entry_put(tree, entry); + if (!ret && zswap_exclusive_loads_enabled) { + zswap_invalidate_entry(tree, entry); + *exclusive = true; + } spin_unlock(&tree->lock); return ret; @@ -1434,13 +1452,7 @@ static void zswap_frontswap_invalidate_page(unsigned type, pgoff_t offset) spin_unlock(&tree->lock); return; } - - /* remove from rbtree */ - zswap_rb_erase(&tree->rbroot, entry); - - /* drop the initial reference from entry creation */ - zswap_entry_put(tree, entry); - + zswap_invalidate_entry(tree, entry); spin_unlock(&tree->lock); } |