On Thu, Sep 24, 2015 at 06:51:52PM +0900, Sergey Senozhatsky wrote: > From: Sergey SENOZHATSKY <[email protected]> > > `mem_used_max' is designed to store the max amount of memory zram > consumed to store the data. However, it does not represent the actual > 'overcommited' (max) value. The existing code goes to -ENOMEM > overcommited case before it updates `->stats.max_used_pages', which > hides the reason we went to -ENOMEM in the first place -- we actually > used more memory than `->limit_pages': > > alloced_pages = zs_get_total_pages(meta->mem_pool); > if (zram->limit_pages && alloced_pages > zram->limit_pages) { > zs_free(meta->mem_pool, handle); > ret = -ENOMEM; > goto out; > } > > update_used_max(zram, alloced_pages); > > Which is misleading. User will see -ENOMEM, check `->limit_pages', > check `->stats.max_used_pages', which will keep the value BEFORE zram > passed `->limit_pages', and see: > `->stats.max_used_pages' < `->limit_pages' > > Move update_used_max() before we do `->limit_pages' check, so that > user will see: > `->stats.max_used_pages' > `->limit_pages' > should the overcommit and -ENOMEM happen. > > Signed-off-by: Sergey Senozhatsky <[email protected]>
It was intent. IOW, I want that max_mem_used is never higher than mem_limit but I realized you are right because user doesn't have way to detect where -ENOMEM is coming from. For example, it could come from mem_limit or real memory alloc fail. Thanks, Sergey. Acked-by: Minchan Kim <[email protected]> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
