| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20240619-swap-allocator-v3-0-e973a3102444@kernel.org>
Date: Wed, 19 Jun 2024 02:20:28 -0700
From: Chris Li <chrisl@...nel.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Kairui Song <kasong@...cent.com>, Ryan Roberts <ryan.roberts@....com>,
"Huang, Ying" <ying.huang@...el.com>, Kairui Song <kasong@...cent.com>,
Kalesh Singh <kaleshsingh@...gle.com>, linux-kernel@...r.kernel.org,
linux-mm@...ck.org, Chris Li <chrisl@...nel.org>,
Barry Song <baohua@...nel.org>
Subject: [PATCH v3 0/2] mm: swap: mTHP swap allocator base on swap cluster
order
This is the short term solutiolns "swap cluster order" listed
in my "Swap Abstraction" discussion slice 8 in the recent
LSF/MM conference.
When commit 845982eb264bc "mm: swap: allow storage of all mTHP
orders" is introduced, it only allocates the mTHP swap entries
from new empty cluster list. It has a fragmentation issue
reported by Barry.
https://lore.kernel.org/all/CAGsJ_4zAcJkuW016Cfi6wicRr8N9X+GJJhgMQdSMp+Ah+NSgNQ@mail.gmail.com/
The reason is that all the empty cluster has been exhausted while
there are planty of free swap entries to in the cluster that is
not 100% free.
Remember the swap allocation order in the cluster.
Keep track of the per order non full cluster list for later allocation.
User impact: For users that allocate and free mix order mTHP swapping,
It greatly improves the success rate of the mTHP swap allocation after the
initial phase.
Barry provides a test program to show the effect:
https://lore.kernel.org/linux-mm/20240615084714.37499-1-21cnbao@gmail.com/
Without:
$ mthp-swapout
Iteration 1: swpout inc: 222, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 2: swpout inc: 219, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 3: swpout inc: 222, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 4: swpout inc: 219, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 5: swpout inc: 110, swpout fallback inc: 117, Fallback percentage: 51.54%
Iteration 6: swpout inc: 0, swpout fallback inc: 230, Fallback percentage: 100.00%
Iteration 7: swpout inc: 0, swpout fallback inc: 229, Fallback percentage: 100.00%
Iteration 8: swpout inc: 0, swpout fallback inc: 223, Fallback percentage: 100.00%
Iteration 9: swpout inc: 0, swpout fallback inc: 224, Fallback percentage: 100.00%
Iteration 10: swpout inc: 0, swpout fallback inc: 216, Fallback percentage: 100.00%
Iteration 11: swpout inc: 0, swpout fallback inc: 212, Fallback percentage: 100.00%
Iteration 12: swpout inc: 0, swpout fallback inc: 224, Fallback percentage: 100.00%
Iteration 13: swpout inc: 0, swpout fallback inc: 214, Fallback percentage: 100.00%
$ mthp-swapout -s
Iteration 1: swpout inc: 222, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 2: swpout inc: 227, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 3: swpout inc: 222, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 4: swpout inc: 224, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 5: swpout inc: 33, swpout fallback inc: 197, Fallback percentage: 85.65%
Iteration 6: swpout inc: 0, swpout fallback inc: 229, Fallback percentage: 100.00%
Iteration 7: swpout inc: 0, swpout fallback inc: 223, Fallback percentage: 100.00%
Iteration 8: swpout inc: 0, swpout fallback inc: 219, Fallback percentage: 100.00%
Iteration 9: swpout inc: 0, swpout fallback inc: 212, Fallback percentage: 100.00%
With:
$ mthp-swapout
Iteration 1: swpout inc: 222, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 2: swpout inc: 219, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 3: swpout inc: 222, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 4: swpout inc: 219, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 5: swpout inc: 227, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 6: swpout inc: 230, swpout fallback inc: 0, Fallback percentage: 0.00%
...
Iteration 94: swpout inc: 224, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 95: swpout inc: 221, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 96: swpout inc: 229, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 97: swpout inc: 219, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 98: swpout inc: 222, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 99: swpout inc: 223, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 100: swpout inc: 224, swpout fallback inc: 0, Fallback percentage: 0.00%
$ mthp-swapout -s
Iteration 1: swpout inc: 222, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 2: swpout inc: 227, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 3: swpout inc: 222, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 4: swpout inc: 224, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 5: swpout inc: 230, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 6: swpout inc: 229, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 7: swpout inc: 223, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 8: swpout inc: 219, swpout fallback inc: 0, Fallback percentage: 0.00%
...
Iteration 94: swpout inc: 223, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 95: swpout inc: 212, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 96: swpout inc: 220, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 97: swpout inc: 220, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 98: swpout inc: 216, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 99: swpout inc: 223, swpout fallback inc: 0, Fallback percentage: 0.00%
Iteration 100: swpout inc: 225, swpout fallback inc: 0, Fallback percentage: 0.00%
Reported-by: Barry Song <21cnbao@...il.com>
Signed-off-by: Chris Li <chrisl@...nel.org>
---
Changes in v3:
- Using V1 as base.
- Rename "next" to "list" for the list field, suggested by Ying.
- Update comment for the locking rules for cluster fields and list,
suggested by Ying.
- Allocate from the nonfull list before attempting free list, suggested
by Kairui.
- Link to v2: https://lore.kernel.org/r/20240614-swap-allocator-v2-0-2a513b4a7f2f@kernel.org
Changes in v2:
- Abandoned.
- Link to v1: https://lore.kernel.org/r/20240524-swap-allocator-v1-0-47861b423b26@kernel.org
---
Chris Li (2):
mm: swap: swap cluster switch to double link list
mm: swap: mTHP allocate swap entries from nonfull list
include/linux/swap.h | 30 +++----
mm/swapfile.c | 248 +++++++++++++++++----------------------------------
2 files changed, 95 insertions(+), 183 deletions(-)
---
base-commit: 19b8422c5bd56fb5e7085995801c6543a98bda1f
change-id: 20240523-swap-allocator-1534c480ece4
Best regards,
--
Chris Li <chrisl@...nel.org>
Powered by blists - more mailing lists