On Mon, 2023-06-19 at 12:25 +0900, Hyeonggon Yoo wrote: > On Tue, Jun 13, 2023 at 06:25:48PM +0530, Jay Patel wrote: > > > <...snip...> > > > > I conducted tests on systems with 160 CPUs and 16 CPUs, > > > > using 4K > > > > and > > > > 64K page sizes. Through these tests, it was observed that the > > > > patch > > > > successfully reduces the wastage of slab memory without any > > > > noticeable > > > > performance degradation in the hackbench test report. However, > > > > it > > > > should > > > > be noted that the patch also increases the total number of > > > > objects, > > > > leading to an overall increase in total slab memory usage. > > > > > > <...snip...> > > > > > > Then my question is that, why is this a useful change if total > > > memory > > > usage is increased? > > > > > This patch aimed in reducing memory wastage can potentially lead to > > an > > increase in the slab order for a slab cache. Consequently, this > > increase in page order can result in a higher number of objects per > > slab, reducing wastage and leading to a more efficient utilization > > of > > memory. > > if you define utilization as percentage of memory that is > being used out of total memory, utilization becomes worse... (based > on data you provided) > > I think 'less memory wastage' is a useful feature only if the total > memory usage is reduced so that it could be used for other purposes. > > I mean, if it consumes more memory on a same workload (in most > cases), > who would like it? Hi Hyeonggon, Thank you for your response. I acknowledge your feedback, and I have made the necessary modifications to the patch. I am pleased to inform you that I have sent the updated version [1], which addresses the issues we discussed. [1] https://lore.kernel.org/linux-mm/20230628095740.589893-1-jaypatel@xxxxxxxxxxxxx/T/#u Thanks, Jay Patel > > > This enhancement is advantageous since the presence of unused > > objects can be leveraged in the future, depending on varying > > workloads. > > At least we need to know when it is leveraged and what kinds of > workloads > would benefit... > > Thanks, >
