From: Mike Kravetz <mike.kravetz@oracle.com> To: Mina Almasry <almasrymina@google.com> Cc: shuah <shuah@kernel.org>, open list <linux-kernel@vger.kernel.org>, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, cgroups@vger.kernel.org, Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Subject: Re: [PATCH v8 2/9] hugetlb_cgroup: add interface for charge/uncharge hugetlb reservations Date: Fri, 8 Nov 2019 16:01:19 -0800 [thread overview] Message-ID: <3f30658c-0e3d-7d5c-4de9-1526b9bac3ce@oracle.com> (raw) In-Reply-To: <CAHS8izMMK2cQMSmnteXA7YTFp2ZoZEm5kUwf8=+6nA+BC49XAQ@mail.gmail.com> On 11/8/19 3:48 PM, Mina Almasry wrote: > On Thu, Nov 7, 2019 at 4:57 PM Mike Kravetz <mike.kravetz@oracle.com> wrote: >> >> On 10/29/19 6:36 PM, Mina Almasry wrote: >>> @@ -22,27 +22,35 @@ struct hugetlb_cgroup; >>> * Minimum page order trackable by hugetlb cgroup. >>> * At least 3 pages are necessary for all the tracking information. >>> */ >>> -#define HUGETLB_CGROUP_MIN_ORDER 2 >>> +#define HUGETLB_CGROUP_MIN_ORDER 3 >> >> Correct me if misremembering, but I think the reson you changed this was >> so that you could use page[3].private. Correct? >> In that case isn't page[3] the last page of an order 2 allocation? >> If my understanding is correct, then leave HUGETLB_CGROUP_MIN_ORDER as is >> and update the preceding comment to say that at least 4 pages are necessary. >> > > Yes, I just misunderstood what MIN_ORDER means. I'll revert the code change. But, do update the comment please. <snip> >>> @@ -85,18 +89,32 @@ static void hugetlb_cgroup_init(struct hugetlb_cgroup *h_cgroup, >>> int idx; >>> >>> for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) { >>> - struct page_counter *counter = &h_cgroup->hugepage[idx]; >>> struct page_counter *parent = NULL; >> >> Should we perhaps rename 'parent' to 'fault_parent' to be consistent? > > Yes that makes sense; will do. > >> That makes me think if perhaps the naming in the previous patch should >> be more explicit. Make the existing names explicitly contin 'fault' as >> the new names contain 'reservation'. >> Just a thought. >> > > You mean change the names of the actual user-facing files? I'm all for > better names but that would break existing users that read/write the > hugetlb_cgroup.2MB.usage_in_bytes/limit_in_bytes users, and so I would > assume is a no-go. > I was thinking about internal variables/definitions such as: +enum { + /* Tracks hugetlb memory faulted in. */ + HUGETLB_RES_USAGE, + /* Tracks hugetlb memory reserved. */ + HUGETLB_RES_RESERVATION_USAGE, + /* Limit for hugetlb memory faulted in. */ + HUGETLB_RES_LIMIT, + /* Limit for hugetlb memory reserved. */ + HUGETLB_RES_RESERVATION_LIMIT, + /* Max usage for hugetlb memory faulted in. */ + HUGETLB_RES_MAX_USAGE, + /* Max usage for hugetlb memory reserved. */ + HUGETLB_RES_RESERVATION_MAX_USAGE, + /* Faulted memory accounting fail count. */ + HUGETLB_RES_FAILCNT, + /* Reserved memory accounting fail count. */ + HUGETLB_RES_RESERVATION_FAILCNT, + HUGETLB_RES_NULL, + HUGETLB_RES_MAX, +}; But, I guess the existing definitions (such as HUGETLB_RES_LIMIT) correspond closely to the externally visible name. In that case, you should leave them as is and ignore my comment. <ship> >>> @@ -126,6 +144,26 @@ static void hugetlb_cgroup_css_free(struct cgroup_subsys_state *css) >>> kfree(h_cgroup); >>> } >>> >>> +static void hugetlb_cgroup_move_parent_reservation(int idx, >>> + struct hugetlb_cgroup *h_cg) >>> +{ >>> + struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(h_cg); >>> + >>> + /* Move the reservation counters. */ >>> + if (!parent_hugetlb_cgroup(h_cg)) { >>> + parent = root_h_cgroup; >>> + /* root has no limit */ >>> + page_counter_charge( >>> + &root_h_cgroup->reserved_hugepage[idx], >>> + page_counter_read( >>> + hugetlb_cgroup_get_counter(h_cg, idx, true))); >>> + } >>> + >>> + /* Take the pages off the local counter */ >>> + page_counter_cancel( >>> + hugetlb_cgroup_get_counter(h_cg, idx, true), >>> + page_counter_read(hugetlb_cgroup_get_counter(h_cg, idx, true))); >>> +} >> >> I know next to nothing about cgroups and am just comparing this to the >> existing hugetlb_cgroup_move_parent() routine. hugetlb_cgroup_move_parent >> updates the cgroup pointer in each page being moved. Do we need to do >> something similar for reservations being moved (move pointer in reservation)? >> > > Oh, good catch. Yes I need to be doing that. I should probably > consolidate those routines so the code doesn't miss things like this. This might get a bit ugly/complicated? Seems like you will need to examine all hugetlbfs inodes and vma's mapping those inodes. -- Mike Kravetz
next prev parent reply other threads:[~2019-11-09 0:01 UTC|newest] Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-10-30 1:36 [PATCH v8 1/9] hugetlb_cgroup: Add hugetlb_cgroup reservation counter Mina Almasry 2019-10-30 1:36 ` [PATCH v8 2/9] hugetlb_cgroup: add interface for charge/uncharge hugetlb reservations Mina Almasry 2019-11-08 0:57 ` Mike Kravetz 2019-11-08 23:48 ` Mina Almasry 2019-11-09 0:01 ` Mike Kravetz [this message] 2019-11-09 0:40 ` Mina Almasry 2019-11-09 0:46 ` Mike Kravetz 2019-11-25 20:26 ` Mina Almasry 2019-11-26 0:05 ` Mike Kravetz 2019-10-30 1:36 ` [PATCH v8 3/9] hugetlb_cgroup: add cgroup-v2 support Mina Almasry 2019-10-30 1:36 ` [PATCH v8 4/9] hugetlb_cgroup: add reservation accounting for private mappings Mina Almasry 2019-10-30 1:36 ` [PATCH v8 5/9] hugetlb: disable region_add file_region coalescing Mina Almasry 2019-11-01 23:23 ` Mike Kravetz 2019-11-04 21:04 ` Mina Almasry 2019-11-04 21:15 ` Mike Kravetz 2019-11-04 21:19 ` Mina Almasry 2019-11-17 11:03 ` Wenkuan Wang 2019-11-18 19:41 ` Mina Almasry 2019-10-30 1:36 ` [PATCH v8 6/9] hugetlb_cgroup: add accounting for shared mappings Mina Almasry 2019-10-30 1:36 ` [PATCH v8 7/9] hugetlb_cgroup: support noreserve mappings Mina Almasry 2019-10-30 1:37 ` [PATCH v8 8/9] hugetlb_cgroup: Add hugetlb_cgroup reservation tests Mina Almasry 2019-10-30 1:37 ` [PATCH v8 9/9] hugetlb_cgroup: Add hugetlb_cgroup reservation docs Mina Almasry 2019-11-07 23:42 ` [PATCH v8 1/9] hugetlb_cgroup: Add hugetlb_cgroup reservation counter Mike Kravetz 2019-11-08 23:35 ` Mina Almasry
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