Re: [PATCH] lightnvm: pblk: take bitmap alloc. out of critical section

From: Javier GonzÃlez
Date: Wed Apr 18 2018 - 07:56:56 EST


> On 17 Apr 2018, at 04.48, Matias BjÃrling <mb@xxxxxxxxxxx> wrote:
>
> On 4/16/18 12:21 PM, Javier GonzÃlez wrote:
>> Allocate line bitmaps outside of the line lock on line preparation.
>> Signed-off-by: Javier GonzÃlez <javier@xxxxxxxxxxxx>
>
>
> The patch description tells what the patch does, it should tell why
> the change the done.
>

Taking an allocation out of a critical zone should be a reason on itself.

>> ---
>> drivers/lightnvm/pblk-core.c | 96 +++++++++++++++++++++++++-------------------
>> 1 file changed, 55 insertions(+), 41 deletions(-)
>> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
>> index 5f960a6609c8..7762e89984ee 100644
>> --- a/drivers/lightnvm/pblk-core.c
>> +++ b/drivers/lightnvm/pblk-core.c
>> @@ -1058,6 +1058,25 @@ static int pblk_line_init_metadata(struct pblk *pblk, struct pblk_line *line,
>> return 1;
>> }
>> +static int pblk_line_alloc_bitmaps(struct pblk *pblk, struct pblk_line *line)
>> +{
>> + struct pblk_line_meta *lm = &pblk->lm;
>> +
>> + line->map_bitmap = kzalloc(lm->sec_bitmap_len, GFP_KERNEL);
>> + if (!line->map_bitmap)
>> + return -ENOMEM;
>> +
>> + /* will be initialized using bb info from map_bitmap */
>> + line->invalid_bitmap = kmalloc(lm->sec_bitmap_len, GFP_KERNEL);
>> + if (!line->invalid_bitmap) {
>> + kfree(line->map_bitmap);
>> + line->map_bitmap = NULL;
>> + return -ENOMEM;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> /* For now lines are always assumed full lines. Thus, smeta former and current
>> * lun bitmaps are omitted.
>> */
>> @@ -1162,18 +1181,7 @@ static int pblk_line_prepare(struct pblk *pblk, struct pblk_line *line)
>> {
>> struct pblk_line_meta *lm = &pblk->lm;
>> int blk_in_line = atomic_read(&line->blk_in_line);
>> - int blk_to_erase, ret;
>> -
>> - line->map_bitmap = kzalloc(lm->sec_bitmap_len, GFP_ATOMIC);
>> - if (!line->map_bitmap)
>> - return -ENOMEM;
>> -
>> - /* will be initialized using bb info from map_bitmap */
>> - line->invalid_bitmap = kmalloc(lm->sec_bitmap_len, GFP_ATOMIC);
>> - if (!line->invalid_bitmap) {
>> - ret = -ENOMEM;
>> - goto fail_free_map_bitmap;
>> - }
>> + int blk_to_erase;
>> /* Bad blocks do not need to be erased */
>> bitmap_copy(line->erase_bitmap, line->blk_bitmap, lm->blk_per_line);
>> @@ -1191,15 +1199,15 @@ static int pblk_line_prepare(struct pblk *pblk, struct pblk_line *line)
>> }
>> if (blk_in_line < lm->min_blk_line) {
>> - ret = -EAGAIN;
>> - goto fail_free_invalid_bitmap;
>> + spin_unlock(&line->lock);
>> + return -EAGAIN;
>> }
>> if (line->state != PBLK_LINESTATE_FREE) {
>> WARN(1, "pblk: corrupted line %d, state %d\n",
>> line->id, line->state);
>> - ret = -EINTR;
>> - goto fail_free_invalid_bitmap;
>> + spin_unlock(&line->lock);
>> + return -EINTR;
>> }
>> line->state = PBLK_LINESTATE_OPEN;
>> @@ -1213,16 +1221,6 @@ static int pblk_line_prepare(struct pblk *pblk, struct pblk_line *line)
>> kref_init(&line->ref);
>> return 0;
>> -
>> -fail_free_invalid_bitmap:
>> - spin_unlock(&line->lock);
>> - kfree(line->invalid_bitmap);
>> - line->invalid_bitmap = NULL;
>> -fail_free_map_bitmap:
>> - kfree(line->map_bitmap);
>> - line->map_bitmap = NULL;
>> -
>> - return ret;
>> }
>> int pblk_line_recov_alloc(struct pblk *pblk, struct pblk_line *line)
>> @@ -1242,13 +1240,15 @@ int pblk_line_recov_alloc(struct pblk *pblk, struct pblk_line *line)
>> }
>> spin_unlock(&l_mg->free_lock);
>> - pblk_rl_free_lines_dec(&pblk->rl, line, true);
>> + if (pblk_line_alloc_bitmaps(pblk, line))
>> + return -EINTR;
>
> Why return -EINTR, instead of the return value from (0, -ENOMEM) from pblk_line_alloc_bitmap?

Sure.

>
>
>> if (!pblk_line_init_bb(pblk, line, 0)) {
>> list_add(&line->list, &l_mg->free_list);
>> return -EINTR;
>> }
>> + pblk_rl_free_lines_dec(&pblk->rl, line, true);
>> return 0;
>> }
>> @@ -1260,6 +1260,24 @@ void pblk_line_recov_close(struct pblk *pblk, struct pblk_line *line)
>> line->emeta = NULL;
>> }
>> +static void pblk_line_clear(struct pblk_line *line)
>> +{
>> + *line->vsc = cpu_to_le32(EMPTY_ENTRY);
>> +
>> + line->map_bitmap = NULL;
>> + line->invalid_bitmap = NULL;
>> + line->smeta = NULL;
>> + line->emeta = NULL;
>> +}
>
> Instead of pblk_line_clear, how about pblk_line_reinit?

Emmmmm... yes, why not.

I'll resend.

Javier

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