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b=SzPCSzAJGs3UGrpf2l5Ux5IkhIojvbrune2DyFgFdqytpk8KxvGYe4xy0mn9cvJpc kTKyQ431BDuqkXn823kR2GrIbjkA5YAe1Els36lu393h7RjRapU5wFEyLCOoGLYhMW f4PoB9ugcvMcYFUp1hEaBnvhfXG+Ul5AgPhr+hXG5ox0OaE1ExDs0fE8arUZslL4+F mJQVLeXzSeHbrF4NiYc8JvdDxe/+yCIj/132zC6+zLpIeitDTEWvzJNLafHfTAdB78 pFgxBJluHzQ0in44PHlF27OJWnRNTy16WwoInCMPZyA3CXaZepPvqKrzQ7uFg0x8VN 4TkDhS5adwhow== Date: Mon, 24 Aug 2026 12:03:05 +0100 From: "Lorenzo Stoakes (ARM)" To: Jinjiang Tu Cc: akpm@linux-foundation.org, david@kernel.org, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, corbet@lwn.net, skhan@linuxfoundation.org, shr@devkernel.io, linux-mm@kvack.org, linux-doc@vger.kernel.org, wangkefeng.wang@huawei.com, sunnanyong@huawei.com Subject: Re: [PATCH v3 2/2] mm/ksm: fix advisor_min_pages_to_scan description Message-ID: References: <20260824061010.3343959-1-tujinjiang@huawei.com> <20260824061010.3343959-3-tujinjiang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260824061010.3343959-3-tujinjiang@huawei.com> X-Rspam-User: X-Stat-Signature: ps4ubyofnmw65e1ymgx1wwkijrj9fxy1 X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 22F4318000E X-HE-Tag: 1787569391-137605 X-HE-Meta: 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 iUHnHAOY qz8WzlAxKwPQveIgRYOut2iFEYgihMnbriPGaV8H8XTZkg6axfMuPHwllOyUvwZX5aKQSZbLygiy5Fpw8BrSphwPPkfA1llAZRIxXgu/O/TjAcmZMtU7tos92KT01LPEj6slrApVe/EL1As8clwK4K4QtYMPqN6E/dz2NzN+sY2jDhyVCi1tXKp6ki7AXNC/6xDkzwlPRTfQJRq17aeegG4f45acDiU6WBIedF1qdTgzc1gXmQidCmwa1SfGRVQc5x9UqE2xVZct/FACp3cg2lo3pu9NM7/cSVKhen6ZSDZZEVuvlMu/P78nJhqHMDBlPzqJoVyPj5k1Kxobqzp/PB39FZJYMjRd95GWR Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Aug 24, 2026 at 02:10:10PM +0800, Jinjiang Tu wrote: > Both Documentation/admin-guide/mm/ksm.rst and the comment next to the > variable definition in mm/ksm.c describe advisor_min_pages_to_scan as a > lower limit of the pages_to_scan parameter, but that is not how the > scan-time advisor actually uses it. commit 4e5fa4f5eff6 ("mm/ksm: add ksm > advisor") only uses it to initialize ksm_thread_pages_to_scan when the > scan-time advisor is enabled. > > ksm_thread_pages_to_scan is adjusted by scan_time_advisor() after a full > scan finishes. ksm_thread_pages_to_scan could be increased or decreased > depend on the real scan time is longer or shorter than the target scan > time. The min value of ksm_thread_pages_to_scan is only limited by > KSM_ADVISOR_MIN_CPU, so ksm_thread_pages_to_scan could be smaller than > ksm_advisor_min_pages_to_scan. > > The semantics of advisor_min_pages_to_scan was updated in the v2 patchset > [1], but the documentation wasn't updated. > > Update the documentation and comment to match the semantics of > advisor_min_pages_to_scan. > > Link: https://lore.kernel.org/linux-mm/20231028000945.2428830-2-shr@devkernel.io/ [1] > Signed-off-by: Jinjiang Tu LGTM so: Reviewed-by: Lorenzo Stoakes (ARM) > --- > Documentation/admin-guide/mm/ksm.rst | 4 ++-- > mm/ksm.c | 2 +- > 2 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst > index c9f533b10f6f..c329ca747b8c 100644 > --- a/Documentation/admin-guide/mm/ksm.rst > +++ b/Documentation/admin-guide/mm/ksm.rst > @@ -183,8 +183,8 @@ advisor_target_scan_time > pages. The default value is 200 seconds. > > advisor_min_pages_to_scan > - specifies the lower limit of the ``pages_to_scan`` parameter of the > - scan time advisor. The default is 500. > + specifies the initial value of the ``pages_to_scan`` parameter of > + the scan time advisor. The default is 500. > > advisor_max_pages_to_scan > specifies the upper limit of the ``pages_to_scan`` parameter of the > diff --git a/mm/ksm.c b/mm/ksm.c > index 7d5b76478f0b..4a6cf8cf5d60 100644 > --- a/mm/ksm.c > +++ b/mm/ksm.c > @@ -342,7 +342,7 @@ static enum ksm_advisor_type ksm_advisor; > * Only called through the sysfs control interface: > */ > > -/* At least scan this many pages per batch. */ > +/* Initial number of pages to scan per batch. */ > static unsigned long ksm_advisor_min_pages_to_scan = 500; > > static void set_advisor_defaults(void) > -- > 2.43.0 > -- Cheers, Lorenzo