Re: [PATCH v4 7/7] zram: writeback throttle
On (12/03/18 15:02), Sergey Senozhatsky wrote: > Seems like I misread writeback_limit_store() a bit. > > So, if I want to, say, let only 10M of writteback pages, I need to > do > > echo 0 > writeback_limit > echo 10M > writeback_limit_store// memparse format is for > // simplicity only; I know > // it should be in 4K units. > > every day. How about dropping the "echo 0" and ->stop_writeback? Ah, this breaks the unlimited writeback. So, nevermind my comment. -ss
Re: [PATCH v4 7/7] zram: writeback throttle
On (12/03/18 15:02), Sergey Senozhatsky wrote: > Seems like I misread writeback_limit_store() a bit. > > So, if I want to, say, let only 10M of writteback pages, I need to > do > > echo 0 > writeback_limit > echo 10M > writeback_limit_store// memparse format is for > // simplicity only; I know > // it should be in 4K units. > > every day. How about dropping the "echo 0" and ->stop_writeback? Ah, this breaks the unlimited writeback. So, nevermind my comment. -ss
Re: [PATCH v4 7/7] zram: writeback throttle
On (12/03/18 14:50), Sergey Senozhatsky wrote:
> On (12/03/18 11:40), Minchan Kim wrote:
> [..]
> > + down_read(>init_lock);
> > + atomic64_set(>stats.bd_wb_limit, val);
> > + if (val == 0)
> > + zram->stop_writeback = false;
> > + up_read(>init_lock);
>
> [..]
>
> > + if (zram->stop_writeback) {
> > + ret = -EIO;
> > + break;
> > + }
> > +
> > if (!blk_idx) {
> > blk_idx = alloc_block_bdev(zram);
> > if (!blk_idx) {
> > @@ -694,6 +732,11 @@ static ssize_t writeback_store(struct device *dev,
> > zram_set_element(zram, index, blk_idx);
> > blk_idx = 0;
> > atomic64_inc(>stats.pages_stored);
> > + if (atomic64_add_unless(>stats.bd_wb_limit,
> > + -1 << (PAGE_SHIFT - 12), 0)) {
> > + if (atomic64_read(>stats.bd_wb_limit) == 0)
> > + zram->stop_writeback = true;
> > + }
>
> Do we need ->stop_writeback? It should be identical to
>
> atomic64_read(>stats.bd_wb_limit) == 0
Seems like I misread writeback_limit_store() a bit.
So, if I want to, say, let only 10M of writteback pages, I need to
do
echo 0 > writeback_limit
echo 10M > writeback_limit_store// memparse format is for
// simplicity only; I know
// it should be in 4K units.
every day. How about dropping the "echo 0" and ->stop_writeback?
So then we can just do
echo 10M > writeback_limit_store
every day: if we have ->bd_wb_limit budget then we writeback,
otherwise we don't.
-ss
Re: [PATCH v4 7/7] zram: writeback throttle
On (12/03/18 14:50), Sergey Senozhatsky wrote:
> On (12/03/18 11:40), Minchan Kim wrote:
> [..]
> > + down_read(>init_lock);
> > + atomic64_set(>stats.bd_wb_limit, val);
> > + if (val == 0)
> > + zram->stop_writeback = false;
> > + up_read(>init_lock);
>
> [..]
>
> > + if (zram->stop_writeback) {
> > + ret = -EIO;
> > + break;
> > + }
> > +
> > if (!blk_idx) {
> > blk_idx = alloc_block_bdev(zram);
> > if (!blk_idx) {
> > @@ -694,6 +732,11 @@ static ssize_t writeback_store(struct device *dev,
> > zram_set_element(zram, index, blk_idx);
> > blk_idx = 0;
> > atomic64_inc(>stats.pages_stored);
> > + if (atomic64_add_unless(>stats.bd_wb_limit,
> > + -1 << (PAGE_SHIFT - 12), 0)) {
> > + if (atomic64_read(>stats.bd_wb_limit) == 0)
> > + zram->stop_writeback = true;
> > + }
>
> Do we need ->stop_writeback? It should be identical to
>
> atomic64_read(>stats.bd_wb_limit) == 0
Seems like I misread writeback_limit_store() a bit.
So, if I want to, say, let only 10M of writteback pages, I need to
do
echo 0 > writeback_limit
echo 10M > writeback_limit_store// memparse format is for
// simplicity only; I know
// it should be in 4K units.
every day. How about dropping the "echo 0" and ->stop_writeback?
So then we can just do
echo 10M > writeback_limit_store
every day: if we have ->bd_wb_limit budget then we writeback,
otherwise we don't.
-ss
Re: [PATCH v4 7/7] zram: writeback throttle
On (12/03/18 11:40), Minchan Kim wrote:
[..]
> + down_read(>init_lock);
> + atomic64_set(>stats.bd_wb_limit, val);
> + if (val == 0)
> + zram->stop_writeback = false;
> + up_read(>init_lock);
[..]
> + if (zram->stop_writeback) {
> + ret = -EIO;
> + break;
> + }
> +
> if (!blk_idx) {
> blk_idx = alloc_block_bdev(zram);
> if (!blk_idx) {
> @@ -694,6 +732,11 @@ static ssize_t writeback_store(struct device *dev,
> zram_set_element(zram, index, blk_idx);
> blk_idx = 0;
> atomic64_inc(>stats.pages_stored);
> + if (atomic64_add_unless(>stats.bd_wb_limit,
> + -1 << (PAGE_SHIFT - 12), 0)) {
> + if (atomic64_read(>stats.bd_wb_limit) == 0)
> + zram->stop_writeback = true;
> + }
Do we need ->stop_writeback? It should be identical to
atomic64_read(>stats.bd_wb_limit) == 0
Otherwise, looks good!
-ss
Re: [PATCH v4 7/7] zram: writeback throttle
On (12/03/18 11:40), Minchan Kim wrote:
[..]
> + down_read(>init_lock);
> + atomic64_set(>stats.bd_wb_limit, val);
> + if (val == 0)
> + zram->stop_writeback = false;
> + up_read(>init_lock);
[..]
> + if (zram->stop_writeback) {
> + ret = -EIO;
> + break;
> + }
> +
> if (!blk_idx) {
> blk_idx = alloc_block_bdev(zram);
> if (!blk_idx) {
> @@ -694,6 +732,11 @@ static ssize_t writeback_store(struct device *dev,
> zram_set_element(zram, index, blk_idx);
> blk_idx = 0;
> atomic64_inc(>stats.pages_stored);
> + if (atomic64_add_unless(>stats.bd_wb_limit,
> + -1 << (PAGE_SHIFT - 12), 0)) {
> + if (atomic64_read(>stats.bd_wb_limit) == 0)
> + zram->stop_writeback = true;
> + }
Do we need ->stop_writeback? It should be identical to
atomic64_read(>stats.bd_wb_limit) == 0
Otherwise, looks good!
-ss
