The patch titled
Subject: mm: zswap: always shrink in zswap_store() if zswap_pool_reached_full
has been added to the -mm mm-unstable branch. Its filename is
mm-zswap-always-shrink-in-zswap_store-if-zswap_pool_reached_full.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-zswap-always-shrink-in-zswap_store-if-zswap_pool_reached_full.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Subject: mm: zswap: always shrink in zswap_store() if zswap_pool_reached_full
Date: Sat, 13 Apr 2024 02:24:04 +0000
Patch series "zswap same-filled and limit checking cleanups", v3.
Miscellaneous cleanups for limit checking and same-filled handling in the
store path. This series was broken out of the "zswap: store zero-filled
pages more efficiently" series [1]. It contains the cleanups and drops
the main functional changes.
[1]https://lore.kernel.org/lkml/20240325235018.2028408-1-yosryahmed@xxxxxxxxxx/
This patch (of 4):
The cleanup code in zswap_store() is not pretty, particularly the 'shrink'
label at the bottom that ends up jumping between cleanup labels.
Instead of having a dedicated label to shrink the pool, just use
zswap_pool_reached_full directly to figure out if the pool needs
shrinking. zswap_pool_reached_full should be true if and only if the pool
needs shrinking.
The only caveat is that the value of zswap_pool_reached_full may be
changed by concurrent zswap_store() calls between checking the limit and
testing zswap_pool_reached_full in the cleanup code. This is fine
because:
- If zswap_pool_reached_full was true during limit checking then became
false during the cleanup code, then someone else already took care of
shrinking the pool and there is no need to queue the worker. That
would be a good change.
- If zswap_pool_reached_full was false during limit checking then became
true during the cleanup code, then someone else hit the limit
meanwhile. In this case, both threads will try to queue the worker,
but it never gets queued more than once anyway. Also, calling
queue_work() multiple times when the limit is hit could already happen
today, so this isn't a significant change in any way.
Link: https://lkml.kernel.org/r/20240413022407.785696-1-yosryahmed@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20240413022407.785696-2-yosryahmed@xxxxxxxxxx
Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Reviewed-by: Nhat Pham <nphamcs@xxxxxxxxx>
Reviewed-by: Chengming Zhou <chengming.zhou@xxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: "Maciej S. Szmigiero" <mail@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/zswap.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
--- a/mm/zswap.c~mm-zswap-always-shrink-in-zswap_store-if-zswap_pool_reached_full
+++ a/mm/zswap.c
@@ -1429,12 +1429,12 @@ bool zswap_store(struct folio *folio)
if (cur_pages >= max_pages) {
zswap_pool_limit_hit++;
zswap_pool_reached_full = true;
- goto shrink;
+ goto reject;
}
if (zswap_pool_reached_full) {
if (cur_pages > zswap_accept_thr_pages())
- goto shrink;
+ goto reject;
else
zswap_pool_reached_full = false;
}
@@ -1540,6 +1540,8 @@ freepage:
zswap_entry_cache_free(entry);
reject:
obj_cgroup_put(objcg);
+ if (zswap_pool_reached_full)
+ queue_work(shrink_wq, &zswap_shrink_work);
check_old:
/*
* If the zswap store fails or zswap is disabled, we must invalidate the
@@ -1550,10 +1552,6 @@ check_old:
if (entry)
zswap_entry_free(entry);
return false;
-
-shrink:
- queue_work(shrink_wq, &zswap_shrink_work);
- goto reject;
}
bool zswap_load(struct folio *folio)
_
Patches currently in -mm which might be from yosryahmed@xxxxxxxxxx are
mm-memcg-add-null-check-to-obj_cgroup_put.patch
mm-zswap-remove-unnecessary-check-in-zswap_find_zpool.patch
percpu-clean-up-all-mappings-when-pcpu_map_pages-fails.patch
mm-zswap-remove-nr_zswap_stored-atomic.patch
mm-zswap-always-shrink-in-zswap_store-if-zswap_pool_reached_full.patch
mm-zswap-refactor-limit-checking-from-zswap_store.patch
mm-zswap-move-more-same-filled-pages-checks-outside-of-zswap_store.patch
mm-zswap-remove-same_filled-module-params.patch
mm-zswap-remove-same_filled-module-params-fix.patch
