linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
From: Mike Kravetz <mike.kravetz@oracle.com>
To: Mina Almasry <almasrymina@google.com>
Cc: shuah@kernel.org, rientjes@google.com, shakeelb@google.com,
	gthelen@google.com, akpm@linux-foundation.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-kselftest@vger.kernel.org, cgroups@vger.kernel.org
Subject: Re: [PATCH v11 4/9] hugetlb: disable region_add file_region coalescing
Date: Wed, 5 Feb 2020 15:57:17 -0800	[thread overview]
Message-ID: <cd457f80-2624-f524-36ce-f11b56b30f8a@oracle.com> (raw)
In-Reply-To: <20200203232248.104733-4-almasrymina@google.com>

On 2/3/20 3:22 PM, Mina Almasry wrote:
> A follow up patch in this series adds hugetlb cgroup uncharge info the
> file_region entries in resv->regions. The cgroup uncharge info may
> differ for different regions, so they can no longer be coalesced at
> region_add time. So, disable region coalescing in region_add in this
> patch.
> 
> Behavior change:
> 
> Say a resv_map exists like this [0->1], [2->3], and [5->6].
> 
> Then a region_chg/add call comes in region_chg/add(f=0, t=5).
> 
> Old code would generate resv->regions: [0->5], [5->6].
> New code would generate resv->regions: [0->1], [1->2], [2->3], [3->5],
> [5->6].
> 
> Special care needs to be taken to handle the resv->adds_in_progress
> variable correctly. In the past, only 1 region would be added for every
> region_chg and region_add call. But now, each call may add multiple
> regions, so we can no longer increment adds_in_progress by 1 in region_chg,
> or decrement adds_in_progress by 1 after region_add or region_abort. Instead,
> region_chg calls add_reservation_in_range() to count the number of regions
> needed and allocates those, and that info is passed to region_add and
> region_abort to decrement adds_in_progress correctly.
> 
> We've also modified the assumption that region_add after region_chg
> never fails. region_chg now pre-allocates at least 1 region for
> region_add. If region_add needs more regions than region_chg has
> allocated for it, then it may fail.
> 
> Signed-off-by: Mina Almasry <almasrymina@google.com>
> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>

This is the same as the previous version.  My late comment was that we
need to rethink the disabling of region coalescing.  This is especially
important for private mappings where there will be one region for huge
page.  I know that you are working on this issue.  Please remove my
Reviewed-by: when sending out the next version.

Thanks,
-- 
Mike Kravetz


  reply	other threads:[~2020-02-05 23:57 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-03 23:22 [PATCH v11 1/9] hugetlb_cgroup: Add hugetlb_cgroup reservation counter Mina Almasry
2020-02-03 23:22 ` [PATCH v11 2/9] hugetlb_cgroup: add interface for charge/uncharge hugetlb reservations Mina Almasry
2020-02-05 22:08   ` Mike Kravetz
2020-02-06 18:16     ` Mina Almasry
2020-02-03 23:22 ` [PATCH v11 3/9] hugetlb_cgroup: add reservation accounting for private mappings Mina Almasry
2020-02-05 23:26   ` Mike Kravetz
2020-02-03 23:22 ` [PATCH v11 4/9] hugetlb: disable region_add file_region coalescing Mina Almasry
2020-02-05 23:57   ` Mike Kravetz [this message]
2020-02-06  1:43     ` Mina Almasry
2020-02-06  2:12       ` Mike Kravetz
2020-02-03 23:22 ` [PATCH v11 5/9] hugetlb_cgroup: add accounting for shared mappings Mina Almasry
2020-02-06 19:33   ` Mike Kravetz
2020-02-06 20:09     ` Mina Almasry
2020-02-03 23:22 ` [PATCH v11 6/9] hugetlb_cgroup: support noreserve mappings Mina Almasry
2020-02-06 22:31   ` Mike Kravetz
2020-02-07 18:16     ` Mike Kravetz
2020-02-11 21:35     ` Mina Almasry
2020-02-11 21:51       ` Mike Kravetz
2020-02-03 23:22 ` [PATCH v11 7/9] hugetlb: support file_region coalescing again Mina Almasry
2020-02-07  0:17   ` Mike Kravetz
2020-02-07 18:44     ` Mina Almasry
2020-02-03 23:22 ` [PATCH v11 8/9] hugetlb_cgroup: Add hugetlb_cgroup reservation tests Mina Almasry
2020-02-04 16:26   ` Sandipan Das
2020-02-04 20:36     ` Mina Almasry
2020-02-04 22:33       ` Mina Almasry
2020-02-03 23:22 ` [PATCH v11 9/9] hugetlb_cgroup: Add hugetlb_cgroup reservation docs Mina Almasry
2020-02-05 19:36 ` [PATCH v11 1/9] hugetlb_cgroup: Add hugetlb_cgroup reservation counter Mike Kravetz

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=cd457f80-2624-f524-36ce-f11b56b30f8a@oracle.com \
    --to=mike.kravetz@oracle.com \
    --cc=akpm@linux-foundation.org \
    --cc=almasrymina@google.com \
    --cc=cgroups@vger.kernel.org \
    --cc=gthelen@google.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=rientjes@google.com \
    --cc=shakeelb@google.com \
    --cc=shuah@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).