On Tue, 2 Jul 2024 12:57:28 +0000 Xiu Jianfeng <xiujianfeng@xxxxxxxxxx> wrote: > Introduce peak and rsvd.peak to v2 to show the historical maximum > usage of resources, as in some scenarios it is necessary to configure > the value of max/rsvd.max based on the peak usage of resources. > The review for this patch was not compelling, so I'll drop this copy for now. If you continue to believe that we should add this to Linux, please resend, perhaps with additional changelog details to help convince others. From: Xiu Jianfeng <xiujianfeng@xxxxxxxxxx> Subject: mm/hugetlb_cgroup: introduce peak and rsvd.peak to v2 Date: Tue, 2 Jul 2024 12:57:28 +0000 Introduce peak and rsvd.peak to v2 to show the historical maximum usage of resources, as in some scenarios it is necessary to configure the value of max/rsvd.max based on the peak usage of resources. Since HugeTLB doesn't support page reclaim, enforcing the limit at page fault time implies that, the application will get SIGBUS signal if it tries to fault in HugeTLB pages beyond its limit. Therefore the application needs to know exactly how many HugeTLB pages it uses before hand, and the sysadmin needs to make sure that there are enough available on the machine for all the users to avoid processes getting SIGBUS. When running some open-source software, it may not be possible to know the exact amount of hugetlb it consumes, so cannot correctly configure the max value. If there is a peak metric, we can run the open-source software first and then configure the max based on the peak value. In cgroup v1, the hugetlb controller provides the max_usage_in_bytes and rsvd.max_usage_in_bytes interface to display the historical maximum usage, so introduce peak and rsvd.peak to v2 to address this issue. Link: https://lkml.kernel.org/r/20240702125728.2743143-1-xiujianfeng@xxxxxxxxxx Signed-off-by: Xiu Jianfeng <xiujianfeng@xxxxxxxxxx> Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx> Cc: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Cc: Zefan Li <lizefan.x@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/admin-guide/cgroup-v2.rst | 8 ++++++++ mm/hugetlb_cgroup.c | 19 +++++++++++++++++++ 2 files changed, 27 insertions(+) --- a/Documentation/admin-guide/cgroup-v2.rst~mm-hugetlb_cgroup-introduce-peak-and-rsvdpeak-to-v2 +++ a/Documentation/admin-guide/cgroup-v2.rst @@ -2659,6 +2659,14 @@ HugeTLB Interface Files hugetlb pages of <hugepagesize> in this cgroup. Only active in use hugetlb pages are included. The per-node values are in bytes. + hugetlb.<hugepagesize>.peak + Show historical maximum usage for "hugepagesize" hugetlb. It exists + for all the cgroup except root. + + hugetlb.<hugepagesize>.rsvd.peak + Show historical maximum usage for "hugepagesize" hugetlb reservations. + It exists for all the cgroup except root. + Misc ---- --- a/mm/hugetlb_cgroup.c~mm-hugetlb_cgroup-introduce-peak-and-rsvdpeak-to-v2 +++ a/mm/hugetlb_cgroup.c @@ -583,6 +583,13 @@ static int hugetlb_cgroup_read_u64_max(s else seq_printf(seq, "%llu\n", val * PAGE_SIZE); break; + case RES_RSVD_MAX_USAGE: + counter = &h_cg->rsvd_hugepage[idx]; + fallthrough; + case RES_MAX_USAGE: + val = (u64)counter->watermark; + seq_printf(seq, "%llu\n", val * PAGE_SIZE); + break; default: BUG(); } @@ -739,6 +746,18 @@ static struct cftype hugetlb_dfl_tmpl[] .seq_show = hugetlb_cgroup_read_u64_max, .flags = CFTYPE_NOT_ON_ROOT, }, + { + .name = "peak", + .private = RES_MAX_USAGE, + .seq_show = hugetlb_cgroup_read_u64_max, + .flags = CFTYPE_NOT_ON_ROOT, + }, + { + .name = "rsvd.peak", + .private = RES_RSVD_MAX_USAGE, + .seq_show = hugetlb_cgroup_read_u64_max, + .flags = CFTYPE_NOT_ON_ROOT, + }, { .name = "events", .seq_show = hugetlb_events_show, _
