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b=VHfZfolzleqbPbPN8K5KO0ppPQt0EK9ZpANQ6jYw27vrg6fRixZwA05ydbsfKEkPo 6nLEbD8zPAyIRgS4lapOARz5nMYfm5tKhFuYJc7PVsrOhnIQI9Ajhrl2WA4PGkx8BU yQ3Xe32uy/I5+4v/3BIpZkgaYz8F85CSBm/8JcaZel3TSMZKWR0JZ9kEBNqT1Qt+yV jrxn/G1WGsod1zizhKEZJALmNliX7cu73XJxUng82rF45M3n/zCfSjX/VlqOlVpa0O H8G44jCwUdx3a5AUfY2zCKkhX1RSEW1CCm4e3GBElCcrLlfMbWkwBZO8wqwLEdham1 f+OruzL71z0bA== Message-ID: <728a4a48-a2cc-4e0b-9c35-054ee0c31e78@kernel.org> Date: Thu, 24 Sep 2026 09:26:43 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC 7/8] mm, slab: add slab_tiny boot param Content-Language: en-US To: Harry Yoo Cc: Hao Li , Christoph Lameter , David Rientjes , Roman Gushchin , Geert Uytterhoeven , Conor Dooley , Damien Le Moal , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260923-slub_tiny_rework-v1-0-a0e66d536eb5@kernel.org> <20260923-slub_tiny_rework-v1-7-a0e66d536eb5@kernel.org> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSNWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBrZXJuZWwub3JnPsLBsAQTAQoAWhYhBKlA1DSZLC6OmRA9UCJPp+fM gqZkBQJqFFy6GxSAAAAAAAQADm1hbnUyLDIuNSsxLjEyLDIsMgIbAwUJGtCBUAULCQgHAwUV CgkICwUWAgMBAAIeBQIXgAAKCRAiT6fnzIKmZJIUEADFx/tREzUImHrEwVHeSvDFmA7tJysI UVrlvrM09E7GIuzphzv7jYmo8n3ANpCczLEVr4G0syYQdTigaZgv3+FQDIIzhKih1IHhu1Ei XHlywNWKnQxxQEUNi5Mwx43wQz5XVw9F1A7gtKBKNtfogO511hAbrzagrYajyQacEJ/+sfhZ 9Da8ltHIXD8pcYaHUfQgEusCgmEd9+KrUwrTbckFKmYq5chuE6yJ4J0EmWknL096jIE6CnzF FRslQ3B1UKDjxVsm1ZHfir5NeWszLkTvGFsddFaWTgh8UycESG6VQzKXjjewXu2pG7YQYRpj QKm1W5X2TkwWkXRBZTmfmbhxIUMh3+zf5wQ463rSmDN/8v81tdqBtAW6rH/kzg1GvkaTHXn0 507yEHFzBksk2viAuIxxr7km8+/KARYLIdGtx30EG8cKzAUZOK6WqxtNCsXUJNrVE8CWrCaD icoNu7Fs1c5hmPHdSTnU48ce67449DdnO4neLSNhRiGlMHJgfJUmgrxu/hcYeOZ3haWmEQ2w uW1Mh01OHi8QZHCEyAbABrPs9GUgccc/4eYXX9hIgxfSkYzn8f+8NuIFPWl/0uTvjgqU29FQ SbzOLxHq9439Ox40G5mS5eZXRGxITYR+6TXvRGI6P/264jvflnr/pDGUttaikU+0W+1uxgKH cmYbEc7ATQRbGTU1AQgAn0H6UrFiWcovkh6EXVcl+SeqyO6JHOPm+e9Wu0Vw+VIUvXZVUVVQ La1PQDUi6j00ChlcR66g9/V0sPIcSutacPKfdKYOBvzd4rlhL8rfrdEsQw5ApZxrA8kYZVMh FmBRKAa6wos25moTlMKpCWzTH84+WO5+ziCTsTUZASAToz3RdunTD+vQcHj0GqNTPAHK63sf bAB2I0BslZkXkY1RLb/YhuA6E7JyEd2pilZOrIuBGl/5q2qSakgnAVFWFBR/DO27JuAksYnq +aH8vI0xGvwn75KqSk4UzAkDzWSmO4ZHuahKtQgZNsMYV+PGayRBX9b9zbldzopoLBdqHc4n jQARAQABwsF8BBgBCgAmAhsMFiEEqUDUNJksLo6ZED1QIk+n58yCpmQFAmfIHFQFCRYU6J8A CgkQIk+n58yCpmS2PA//bqN1LfcotmArgElsa+0EGZSQlYgK48pm8WAeTXTngudP9IJ4SuKY HR5RNjHcBeqN+Me0zxRqYzRb8nGanHEkDyf4Im8DQM8d6vbyU+FcPmG4skud4kgS1zMHnlVd SXfSIwKC/hKgdHG8aBV7545Lz9X6Iohea+94wneD0aw/hqF+QWewGZhWJriWAZtvEkzNjQOi 4U9F/trLten/x7bpphDSnDMKJtITbtzATT1Dq7o7VpIUK1nCTQALMuMjKCdi8OdU/+V+R3O4 0PXWvX8qrvqYapVbZ+9KqT74FsuB0Ya9uXwgBF2Q6cRuETZk5vqaqKxzqoQZCO8AOz/58j6O 2RHNy/mZEN+7tJ5Tsq42zVJ4jxsT8b9YplavCMsnBgDeRWhcbYhCyttoL7nYISyWg4kQYZ/P wIV3OuNv2f8iKYsxNsRuClOAF82+gvqOy1/1pprFjy8uo2pkoOrb63aOP3vO5VHnRKgra6dq NcaZ+c6J4H+nEJGi2SkHAUJz5oBzuThvPudLvPA/SK8sKoM01IRxSihev/S/5WLazXB1PGem OCbvzC1IjWJJraxiDJ5IygokapUa2RP7+WBR22skQ3SSl6G107QgWKSyTOGWEaRmV53vxQLV jXuCmzSSasTL60zq5yGrT4/DYQVSNEUiUbG4pYekxJujNeEDkUlky0Y= In-Reply-To: <20260923-slub_tiny_rework-v1-7-a0e66d536eb5@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 2EDB41C0004 X-Stat-Signature: 19q7r7dekhx6jyweg7sckmszuh4fw3ag X-HE-Tag: 1790234808-152460 X-HE-Meta: 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 Qpu1DHRt 8gt+KMynZHJJ3h+Az//of5/qCdmQRbEeVQS/MDSnaiqia0y7+JHisFH7ans7GqWNwwVsIGkpy62WMxrwtpjXJt6cP0GDpL4G8OogOQdi/HMtQTbVHxGl/etge8sxM6UDqpeGEMa36lf0tHkLY8ObpAGIQww6oUGhkMyPDQjQTjsB8hhWTnz4VdHdY6R53oVYCp+I5LBTr5zUo8DOFvwgMueThLi1IkKE5F0JbXnS3YALh/6kI0Nwvj/WbQGJAshj9MUFcyLh/X9Lb4vSmpznFh4q+i+BGZddAgShIHEnw/m62mnPaj8UuWpM/IkeXs7j0wyVJng+pyg0ooUo= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/23/26 17:45, Vlastimil Babka (SUSE) wrote: > In order to deprecate the CONFIG_SLUB_TINY option, introduce an early > boot param slab_tiny to control the value of slab_tiny_enabled. > > As long as CONFIG_SLUB_TINY is still around and enabled, this boot param > can also override it to be disabled. > > Signed-off-by: Vlastimil Babka (SUSE) > --- > Documentation/admin-guide/kernel-parameters.txt | 4 ++++ > Documentation/admin-guide/mm/slab.rst | 5 +++++ > mm/slub.c | 7 +++++++ > 3 files changed, 16 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 33cd30996e47..0100ab00388a 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -7031,6 +7031,10 @@ Kernel parameters > NUMA kernel object placement which helps with slow > interconnects in NUMA systems. > > + slab_tiny= [MM, EARLY] > + Minimize the slab allocator memory footprint at the > + expense of SMP scalability. > + > slram= [HW,MTD] > > smart2= [HW] > diff --git a/Documentation/admin-guide/mm/slab.rst b/Documentation/admin-guide/mm/slab.rst > index 0beeae71d472..6c005d3de0b2 100644 > --- a/Documentation/admin-guide/mm/slab.rst > +++ b/Documentation/admin-guide/mm/slab.rst > @@ -94,6 +94,11 @@ kdump kernels where scalability is not a concern, but memory has to be > > slab_debug=N > > +Note that for this purpose you can instead use an option that can achieve > +slightly better memory savings (by not creating separate kmalloc-rcl caches):: > + > + slab_tiny=1 > + > You can apply different options to different list of slab names, using blocks > of options. This will enable red zoning for dentry and user tracking for > kmalloc. All other slabs will not get any debugging enabled:: > diff --git a/mm/slub.c b/mm/slub.c > index 4814f025fde5..d672809fa2f6 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -8726,6 +8726,13 @@ void __init kmem_cache_init_late(void) > #endif > } > > +static int __init early_slab_tiny(char *buf) > +{ > + return kstrtobool(buf, &slub_tiny_enabled); ^ slab_tiny_enabled missed a place on a last-minute rename. The version in git is fixed: https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=b4/slub_tiny_rework > +} > + > +early_param("slab_tiny", early_slab_tiny); > + > int do_kmem_cache_create(struct kmem_cache *s, const char *name, > unsigned int size, struct kmem_cache_args *args, > slab_flags_t flags) >