Re: [PATCH 0/2] mm,swap: skip swap readahead for instant IO (like zswap)

2020-10-09 Thread Rik van Riel
On Mon, 2020-10-05 at 13:32 -0400, Rik van Riel wrote: > On Tue, 2020-09-22 at 10:12 -0700, Andrew Morton wrote: > > On Mon, 21 Sep 2020 22:01:46 -0400 Rik van Riel > > wrote: > > Any quantitative testing results? > > I have test results with a real workload now. > > Without this patch, enablin

Re: [PATCH 0/2] mm,swap: skip swap readahead for instant IO (like zswap)

2020-10-05 Thread Rik van Riel
On Tue, 2020-09-22 at 10:12 -0700, Andrew Morton wrote: > On Mon, 21 Sep 2020 22:01:46 -0400 Rik van Riel > wrote: > > > Both with frontswap/zswap, and with some extremely fast IO devices, > > swap IO will be done before the "asynchronous" swap_readpage() call > > has returned. > > > > In that c

Re: [PATCH 0/2] mm,swap: skip swap readahead for instant IO (like zswap)

2020-09-22 Thread Andrew Morton
On Mon, 21 Sep 2020 22:01:46 -0400 Rik van Riel wrote: > Both with frontswap/zswap, and with some extremely fast IO devices, > swap IO will be done before the "asynchronous" swap_readpage() call > has returned. > > In that case, doing swap readahead only wastes memory, increases > latency, and i

[PATCH 0/2] mm,swap: skip swap readahead for instant IO (like zswap)

2020-09-21 Thread Rik van Riel
Both with frontswap/zswap, and with some extremely fast IO devices, swap IO will be done before the "asynchronous" swap_readpage() call has returned. In that case, doing swap readahead only wastes memory, increases latency, and increases the chances of needing to evict something more useful from m