Messages in this thread | | | Date | Mon, 3 Dec 2018 15:02:08 +0900 | From | Sergey Senozhatsky <> | Subject | Re: [PATCH v4 7/7] zram: writeback throttle |
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On (12/03/18 14:50), Sergey Senozhatsky wrote: > On (12/03/18 11:40), Minchan Kim wrote: > [..] > > + down_read(&zram->init_lock); > > + atomic64_set(&zram->stats.bd_wb_limit, val); > > + if (val == 0) > > + zram->stop_writeback = false; > > + up_read(&zram->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(&zram->stats.pages_stored); > > + if (atomic64_add_unless(&zram->stats.bd_wb_limit, > > + -1 << (PAGE_SHIFT - 12), 0)) { > > + if (atomic64_read(&zram->stats.bd_wb_limit) == 0) > > + zram->stop_writeback = true; > > + } > > Do we need ->stop_writeback? It should be identical to > > atomic64_read(&zram->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
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