Hi Liang, On Tue, 12 Dec 2023 at 06:47, Liang Chen <liangchen.linux@xxxxxxxxx> wrote: > > Referring to patch [1], in order to support multiple users referencing the > same fragment and prevent overflow from pp_ref_count growing, the initial > value of pp_ref_count is halved, leaving room for pp_ref_count to increment > before the page is drained. > > [1] > https://lore.kernel.org/all/20211009093724.10539-3-linyunsheng@xxxxxxxxxx/ We only need this if patch #4 is merged. In that case, I'd like to describe the changelog a bit better. Something along the lines of "Up to now, we were only subtracting from the number of used page fragments to figure out when a page could be freed or recycled. A following patch introduces support for multiple users referencing the same fragment. So reduce the initial page fragments value to half to avoid overflowing" Thanks /Ilias > same fragment > > Signed-off-by: Liang Chen <liangchen.linux@xxxxxxxxx> > Reviewed-by: Yunsheng Lin <linyunsheng@xxxxxxxxxx> > --- > net/core/page_pool.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/core/page_pool.c b/net/core/page_pool.c > index 106220b1f89c..436f7ffea7b4 100644 > --- a/net/core/page_pool.c > +++ b/net/core/page_pool.c > @@ -26,7 +26,7 @@ > #define DEFER_TIME (msecs_to_jiffies(1000)) > #define DEFER_WARN_INTERVAL (60 * HZ) > > -#define BIAS_MAX LONG_MAX > +#define BIAS_MAX (LONG_MAX >> 1) > > #ifdef CONFIG_PAGE_POOL_STATS > /* alloc_stat_inc is intended to be used in softirq context */ > -- > 2.31.1 >
