Re: [PATCH mm-unstable v1 5/5] mm/swap: remove boilerplate
From: Barry Song
Date: Fri Jul 26 2024 - 01:48:43 EST
On Thu, Jul 11, 2024 at 2:15 PM Yu Zhao <yuzhao@xxxxxxxxxx> wrote:
>
> Remove boilerplate by using a macro to choose the corresponding lock
> and handler for each folio_batch in cpu_fbatches.
>
> Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx>
> ---
> mm/swap.c | 107 +++++++++++++++++++-----------------------------------
> 1 file changed, 37 insertions(+), 70 deletions(-)
>
> diff --git a/mm/swap.c b/mm/swap.c
> index 4a66d2f87f26..342ff4e39ba4 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -220,16 +220,45 @@ static void folio_batch_move_lru(struct folio_batch *fbatch, move_fn_t move_fn)
> folios_put(fbatch);
> }
>
> -static void folio_batch_add_and_move(struct folio_batch *fbatch,
> - struct folio *folio, move_fn_t move_fn)
> +static void __folio_batch_add_and_move(struct folio_batch *fbatch,
> + struct folio *folio, move_fn_t move_fn,
> + bool on_lru, bool disable_irq)
> {
> + unsigned long flags;
> +
> + folio_get(folio);
> +
> + if (on_lru && !folio_test_clear_lru(folio)) {
> + folio_put(folio);
> + return;
> + }
> +
> if (folio_batch_add(fbatch, folio) && !folio_test_large(folio) &&
> !lru_cache_disabled())
> return;
>
> + if (disable_irq)
> + local_lock_irqsave(&cpu_fbatches.lock_irq, flags);
> + else
> + local_lock(&cpu_fbatches.lock);
> +
> folio_batch_move_lru(fbatch, move_fn);
> +
> + if (disable_irq)
> + local_unlock_irqrestore(&cpu_fbatches.lock_irq, flags);
> + else
> + local_unlock(&cpu_fbatches.lock);
> }
>
> +#define folio_batch_add_and_move(folio, op, on_lru) \
> + __folio_batch_add_and_move( \
> + this_cpu_ptr(&cpu_fbatches.op), \
> + folio, \
> + op, \
> + on_lru, \
> + offsetof(struct cpu_fbatches, op) > offsetof(struct cpu_fbatches, lock_irq) \
> + )
I am running into this BUG, is it relevant?
/ # [ 64.908801] check_preemption_disabled: 1804 callbacks suppressed
[ 64.908915] BUG: using smp_processor_id() in preemptible [00000000]
code: jbd2/vda-8/96
[ 64.909912] caller is debug_smp_processor_id+0x20/0x30
[ 64.911743] CPU: 0 UID: 0 PID: 96 Comm: jbd2/vda-8 Not tainted
6.10.0-gef32eccacce2 #59
[ 64.912373] Hardware name: linux,dummy-virt (DT)
[ 64.912741] Call trace:
[ 64.913048] dump_backtrace+0x9c/0x100
[ 64.913414] show_stack+0x20/0x38
[ 64.913761] dump_stack_lvl+0xc4/0x150
[ 64.914197] dump_stack+0x18/0x28
[ 64.914557] check_preemption_disabled+0xd8/0x120
[ 64.914944] debug_smp_processor_id+0x20/0x30
[ 64.915321] folio_add_lru+0x30/0xa8
[ 64.915680] filemap_add_folio+0xe4/0x118
[ 64.916082] __filemap_get_folio+0x178/0x450
[ 64.916455] __getblk_slow+0xb0/0x310
[ 64.916816] bdev_getblk+0x94/0xc0
[ 64.917169] jbd2_journal_get_descriptor_buffer+0x6c/0x1b0
[ 64.917590] jbd2_journal_commit_transaction+0x7f0/0x1c88
[ 64.917994] kjournald2+0xd4/0x278
[ 64.918344] kthread+0x11c/0x128
[ 64.918693] ret_from_fork+0x10/0x20
[ 64.928277] BUG: using smp_processor_id() in preemptible [00000000]
code: jbd2/vda-8/96
[ 64.928878] caller is debug_smp_processor_id+0x20/0x30
[ 64.929381] CPU: 0 UID: 0 PID: 96 Comm: jbd2/vda-8 Not tainted
6.10.0-gef32eccacce2 #59
[ 64.929886] Hardware name: linux,dummy-virt (DT)
[ 64.930252] Call trace:
[ 64.930544] dump_backtrace+0x9c/0x100
[ 64.930907] show_stack+0x20/0x38
[ 64.931255] dump_stack_lvl+0xc4/0x150
[ 64.931616] dump_stack+0x18/0x28
[ 64.932022] check_preemption_disabled+0xd8/0x120
[ 64.932486] debug_smp_processor_id+0x20/0x30
[ 64.933023] folio_add_lru+0x30/0xa8
[ 64.933523] filemap_add_folio+0xe4/0x118
[ 64.933892] __filemap_get_folio+0x178/0x450
[ 64.934265] __getblk_slow+0xb0/0x310
[ 64.934626] bdev_getblk+0x94/0xc0
[ 64.934977] jbd2_journal_get_descriptor_buffer+0x6c/0x1b0
[ 64.935418] journal_submit_commit_record.part.0.constprop.0+0x48/0x288
[ 64.935919] jbd2_journal_commit_transaction+0x1590/0x1c88
[ 64.936519] kjournald2+0xd4/0x278
[ 64.936908] kthread+0x11c/0x128
[ 64.937323] ret_from_fork+0x10/0x20
> +
> static void lru_move_tail(struct lruvec *lruvec, struct folio *folio)
> {
> if (folio_test_unevictable(folio))
> @@ -250,23 +279,11 @@ static void lru_move_tail(struct lruvec *lruvec, struct folio *folio)
> */
> void folio_rotate_reclaimable(struct folio *folio)
> {
> - struct folio_batch *fbatch;
> - unsigned long flags;
> -
> if (folio_test_locked(folio) || folio_test_dirty(folio) ||
> folio_test_unevictable(folio))
> return;
>
> - folio_get(folio);
> - if (!folio_test_clear_lru(folio)) {
> - folio_put(folio);
> - return;
> - }
> -
> - local_lock_irqsave(&cpu_fbatches.lock_irq, flags);
> - fbatch = this_cpu_ptr(&cpu_fbatches.lru_move_tail);
> - folio_batch_add_and_move(fbatch, folio, lru_move_tail);
> - local_unlock_irqrestore(&cpu_fbatches.lock_irq, flags);
> + folio_batch_add_and_move(folio, lru_move_tail, true);
> }
>
> void lru_note_cost(struct lruvec *lruvec, bool file,
> @@ -355,21 +372,10 @@ static void folio_activate_drain(int cpu)
>
> void folio_activate(struct folio *folio)
> {
> - struct folio_batch *fbatch;
> -
> if (folio_test_active(folio) || folio_test_unevictable(folio))
> return;
>
> - folio_get(folio);
> - if (!folio_test_clear_lru(folio)) {
> - folio_put(folio);
> - return;
> - }
> -
> - local_lock(&cpu_fbatches.lock);
> - fbatch = this_cpu_ptr(&cpu_fbatches.lru_activate);
> - folio_batch_add_and_move(fbatch, folio, lru_activate);
> - local_unlock(&cpu_fbatches.lock);
> + folio_batch_add_and_move(folio, lru_activate, true);
> }
>
> #else
> @@ -513,8 +519,6 @@ EXPORT_SYMBOL(folio_mark_accessed);
> */
> void folio_add_lru(struct folio *folio)
> {
> - struct folio_batch *fbatch;
> -
> VM_BUG_ON_FOLIO(folio_test_active(folio) &&
> folio_test_unevictable(folio), folio);
> VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
> @@ -524,11 +528,7 @@ void folio_add_lru(struct folio *folio)
> lru_gen_in_fault() && !(current->flags & PF_MEMALLOC))
> folio_set_active(folio);
>
> - folio_get(folio);
> - local_lock(&cpu_fbatches.lock);
> - fbatch = this_cpu_ptr(&cpu_fbatches.lru_add);
> - folio_batch_add_and_move(fbatch, folio, lru_add);
> - local_unlock(&cpu_fbatches.lock);
> + folio_batch_add_and_move(folio, lru_add, false);
> }
> EXPORT_SYMBOL(folio_add_lru);
>
> @@ -702,22 +702,11 @@ void lru_add_drain_cpu(int cpu)
> */
> void deactivate_file_folio(struct folio *folio)
> {
> - struct folio_batch *fbatch;
> -
> /* Deactivating an unevictable folio will not accelerate reclaim */
> if (folio_test_unevictable(folio))
> return;
>
> - folio_get(folio);
> - if (!folio_test_clear_lru(folio)) {
> - folio_put(folio);
> - return;
> - }
> -
> - local_lock(&cpu_fbatches.lock);
> - fbatch = this_cpu_ptr(&cpu_fbatches.lru_deactivate_file);
> - folio_batch_add_and_move(fbatch, folio, lru_deactivate_file);
> - local_unlock(&cpu_fbatches.lock);
> + folio_batch_add_and_move(folio, lru_deactivate_file, true);
> }
>
> /*
> @@ -730,21 +719,10 @@ void deactivate_file_folio(struct folio *folio)
> */
> void folio_deactivate(struct folio *folio)
> {
> - struct folio_batch *fbatch;
> -
> if (folio_test_unevictable(folio) || !(folio_test_active(folio) || lru_gen_enabled()))
> return;
>
> - folio_get(folio);
> - if (!folio_test_clear_lru(folio)) {
> - folio_put(folio);
> - return;
> - }
> -
> - local_lock(&cpu_fbatches.lock);
> - fbatch = this_cpu_ptr(&cpu_fbatches.lru_deactivate);
> - folio_batch_add_and_move(fbatch, folio, lru_deactivate);
> - local_unlock(&cpu_fbatches.lock);
> + folio_batch_add_and_move(folio, lru_deactivate, true);
> }
>
> /**
> @@ -756,22 +734,11 @@ void folio_deactivate(struct folio *folio)
> */
> void folio_mark_lazyfree(struct folio *folio)
> {
> - struct folio_batch *fbatch;
> -
> if (!folio_test_anon(folio) || !folio_test_swapbacked(folio) ||
> folio_test_swapcache(folio) || folio_test_unevictable(folio))
> return;
>
> - folio_get(folio);
> - if (!folio_test_clear_lru(folio)) {
> - folio_put(folio);
> - return;
> - }
> -
> - local_lock(&cpu_fbatches.lock);
> - fbatch = this_cpu_ptr(&cpu_fbatches.lru_lazyfree);
> - folio_batch_add_and_move(fbatch, folio, lru_lazyfree);
> - local_unlock(&cpu_fbatches.lock);
> + folio_batch_add_and_move(folio, lru_lazyfree, true);
> }
>
> void lru_add_drain(void)
> --
> 2.45.2.803.g4e1b14247a-goog
>
>
Thanks
Barry