From: Chris Li <chrisl@kernel.org>
To: Barry Song <21cnbao@gmail.com>
Cc: Kairui Song <ryncsn@gmail.com>, Lei Liu <liulei.rjpt@vivo.com>,
Michal Hocko <mhocko@suse.com>,
David Rientjes <rientjes@google.com>,
Shakeel Butt <shakeel.butt@linux.dev>,
Andrew Morton <akpm@linux-foundation.org>,
Kemeng Shi <shikemeng@huaweicloud.com>,
Nhat Pham <nphamcs@gmail.com>, Baoquan He <bhe@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
Muchun Song <muchun.song@linux.dev>,
David Hildenbrand <david@redhat.com>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@suse.cz>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Brendan Jackman <jackmanb@google.com>, Zi Yan <ziy@nvidia.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Chen Yu <yu.c.chen@intel.com>, Hao Jia <jiahao1@lixiang.com>,
"Kirill A. Shutemov" <kas@kernel.org>,
Usama Arif <usamaarif642@gmail.com>,
Oleg Nesterov <oleg@redhat.com>,
Christian Brauner <brauner@kernel.org>,
Mateusz Guzik <mjguzik@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Andrii Nakryiko <andrii@kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Fushuai Wang <wangfushuai@baidu.com>,
"open list:MEMORY MANAGEMENT - OOM KILLER" <linux-mm@kvack.org>,
open list <linux-kernel@vger.kernel.org>,
"open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)"
<cgroups@vger.kernel.org>
Subject: Re: [PATCH v0 0/2] mm: swap: Gather swap entries and batch async release
Date: Tue, 9 Sep 2025 09:15:56 -0700 [thread overview]
Message-ID: <CAF8kJuM4BEeHnkhw5bSM6ap23paChMBZtqCY6ksie+8EghYb8g@mail.gmail.com> (raw)
In-Reply-To: <CAGsJ_4xiTteQECtUNBo+eC9uu8R3CgVT2rpvGCGdFqc3psSnWQ@mail.gmail.com>
On Tue, Sep 9, 2025 at 2:24 AM Barry Song <21cnbao@gmail.com> wrote:
> I feel the cover letter does not clearly describe where the bottleneck
> occurs or where the performance gains originate. To be honest, even
> the versions submitted last year did not present the bottleneck clearly.
>
> For example, is this due to lock contention (in which case we would
> need performance data to see how much CPU time is spent waiting for
> locks), or simply because we can simultaneously zap present and
> non-present PTEs?
I have done some long tail analysis of the zswap page fault a while
back, before zswap converting to xarray. For the zswap page fault, in
the long tail a good chunk is a bath free swap slot. The breakdown
inside shows a huge chunk is the clear_shadow() followed by
memsw_uncharge(). I will post the link to the breakdown image once it
is available.
Chris
next prev parent reply other threads:[~2025-09-09 16:16 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-09 6:53 Lei Liu
2025-09-09 6:53 ` [PATCH v0 1/2] mm: swap: Gather swap entries and batch async release core Lei Liu
2025-09-10 1:39 ` kernel test robot
2025-09-10 3:12 ` kernel test robot
2025-09-09 6:53 ` [PATCH v0 2/2] mm: swap: Forced swap entries release under memory pressure Lei Liu
2025-09-10 5:36 ` kernel test robot
2025-09-09 7:30 ` [PATCH v0 0/2] mm: swap: Gather swap entries and batch async release Kairui Song
2025-09-09 9:24 ` Barry Song
2025-09-09 16:15 ` Chris Li [this message]
2025-09-09 18:01 ` Chris Li
2025-09-10 14:07 ` Lei Liu
2025-10-14 20:42 ` Barry Song
2025-09-09 15:38 ` Chris Li
2025-09-10 14:01 ` Lei Liu
2025-09-09 19:21 ` Shakeel Butt
2025-09-09 19:48 ` Suren Baghdasaryan
2025-09-10 14:14 ` Lei Liu
2025-09-10 14:56 ` Suren Baghdasaryan
2025-09-10 16:05 ` Chris Li
2025-09-10 20:12 ` Shakeel Butt
2025-09-11 3:04 ` Lei Liu
2025-09-10 15:40 ` Chris Li
2025-09-10 20:10 ` Shakeel Butt
2025-09-10 20:41 ` Suren Baghdasaryan
2025-09-10 22:10 ` T.J. Mercier
2025-09-10 22:33 ` Shakeel Butt
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