The patch titled Subject: mm/frontswap.c: use non-atomic '__set_bit()' when possible has been added to the -mm tree. Its filename is mm-mempool-use-non-atomic-__set_bit-when-possible.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-mempool-use-non-atomic-__set_bit-when-possible.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-mempool-use-non-atomic-__set_bit-when-possible.patch 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 and is updated there every 3-4 working days ------------------------------------------------------ From: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx> Subject: mm/frontswap.c: use non-atomic '__set_bit()' when possible the 'a' and 'b' bitmaps are local to this function, so no concurrent access can occur. So the non-atomic '__set_bit()' can be used to save a few cycles. Link: https://lkml.kernel.org/r/e52476da5cee57151745c5c3c934a69798dc6fa4.1638132190.git.christophe.jaillet@xxxxxxxxxx Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/frontswap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/mm/frontswap.c~mm-mempool-use-non-atomic-__set_bit-when-possible +++ a/mm/frontswap.c @@ -127,7 +127,7 @@ void frontswap_register_ops(struct front spin_lock(&swap_lock); plist_for_each_entry(si, &swap_active_head, list) { if (!WARN_ON(!si->frontswap_map)) - set_bit(si->type, a); + __set_bit(si->type, a); } spin_unlock(&swap_lock); @@ -149,7 +149,7 @@ void frontswap_register_ops(struct front spin_lock(&swap_lock); plist_for_each_entry(si, &swap_active_head, list) { if (si->frontswap_map) - set_bit(si->type, b); + __set_bit(si->type, b); } spin_unlock(&swap_lock); _ Patches currently in -mm which might be from christophe.jaillet@xxxxxxxxxx are mm-mempool-use-non-atomic-__set_bit-when-possible.patch