The patch titled
Subject: Revert "frontswap: simplify frontswap_register_ops"
has been added to the -mm mm-unstable branch. Its filename is
revert-frontswap-simplify-frontswap_register_ops.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/revert-frontswap-simplify-frontswap_register_ops.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Liu Shixin <liushixin2@xxxxxxxxxx>
Subject: Revert "frontswap: simplify frontswap_register_ops"
Date: Mon, 29 Aug 2022 21:22:59 +0800
This reverts commit f328c1d16e4c764992895ac9c9425cea861b2ca0.
Since we plan to delay zswap initializaton, we need to invoke ops->init
for swap devices which are already online when registering backend.
Link: https://lkml.kernel.org/r/20220829132302.3367054-4-liushixin2@xxxxxxxxxx
Signed-off-by: Liu Shixin <liushixin2@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Dan Streetman <ddstreet@xxxxxxxx>
Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Nathan Chancellor <nathan@xxxxxxxxxx>
Cc: Seth Jennings <sjenning@xxxxxxxxxx>
Cc: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/frontswap.c | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
--- a/mm/frontswap.c~revert-frontswap-simplify-frontswap_register_ops
+++ a/mm/frontswap.c
@@ -99,6 +99,25 @@ static inline void inc_frontswap_invalid
*/
void frontswap_register_ops(struct frontswap_ops *ops)
{
+ DECLARE_BITMAP(a, MAX_SWAPFILES);
+ DECLARE_BITMAP(b, MAX_SWAPFILES);
+ struct swap_info_struct *si;
+ unsigned int i;
+
+ bitmap_zero(a, MAX_SWAPFILES);
+ bitmap_zero(b, MAX_SWAPFILES);
+
+ spin_lock(&swap_lock);
+ plist_for_each_entry(si, &swap_active_head, list) {
+ if (!WARN_ON(!si->frontswap_map))
+ __set_bit(si->type, a);
+ }
+ spin_unlock(&swap_lock);
+
+ /* the new ops needs to know the currently active swap devices */
+ for_each_set_bit(i, a, MAX_SWAPFILES)
+ ops->init(i);
+
/*
* Setting frontswap_ops must happen after the ops->init() calls
* above; cmpxchg implies smp_mb() which will ensure the init is
@@ -109,6 +128,28 @@ void frontswap_register_ops(struct front
} while (cmpxchg(&frontswap_ops, ops->next, ops) != ops->next);
static_branch_inc(&frontswap_enabled_key);
+
+ spin_lock(&swap_lock);
+ plist_for_each_entry(si, &swap_active_head, list) {
+ if (si->frontswap_map)
+ __set_bit(si->type, b);
+ }
+ spin_unlock(&swap_lock);
+
+ /*
+ * On the very unlikely chance that a swap device was added or
+ * removed between setting the "a" list bits and the ops init
+ * calls, we re-check and do init or invalidate for any changed
+ * bits.
+ */
+ if (unlikely(!bitmap_equal(a, b, MAX_SWAPFILES))) {
+ for (i = 0; i < MAX_SWAPFILES; i++) {
+ if (!test_bit(i, a) && test_bit(i, b))
+ ops->init(i);
+ else if (test_bit(i, a) && !test_bit(i, b))
+ ops->invalidate_area(i);
+ }
+ }
}
/*
_
Patches currently in -mm which might be from liushixin2@xxxxxxxxxx are
revert-frontswap-remove-support-for-multiple-ops.patch
revert-mm-mark-swap_lock-and-swap_active_head-static.patch
revert-frontswap-simplify-frontswap_register_ops.patch
mm-zswap-replace-zswap_init_started-failed-with-zswap_init_state.patch
mm-zswap-delay-the-initializaton-of-zswap-until-the-first-enablement.patch
mm-zswap-skip-confusing-print-info.patch
