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b=Qm9RBWiCNRRPZwoAE/MGVvcH1Fb0Bq5Z4VYyttWdudvb2XA3c15rpA8dayNhJTmUa WNyM7eDlgDYa4S5PYFDRhR9bf89NkOoLmgy62i3y7aIpt3H2QeEXuEpwRX2w6ft4Ia mAy0zTswlIo2jcv1xq/37MZNbvndohUPQTV6gNGXj+zj/8zpI2s8EJU7Gz46n+4fKs +hIpY7IKelaY2ulXUQRL5H1nMWAFaIfYUb8xvZtt0cnXzP80i+SgENOLx4OsCPvxvI 4oj3coRJv6+0ENBXpkuR0kBSE7Luhf587W4eu/ohVWswm934fBm/qIsHgCppYefjcS 7RMb12iu8M4gA== Date: Thu, 18 Sep 2025 13:33:33 +0300 From: Mike Rapoport To: Dev Jain Cc: akpm@linux-foundation.org, ryan.roberts@arm.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: Remove PMD alignment constraint in execmem_vmalloc() Message-ID: References: <20250918093453.75676-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250918093453.75676-1-dev.jain@arm.com> X-Rspamd-Queue-Id: A8114C0008 X-Rspam-User: X-Rspamd-Server: rspam07 X-Stat-Signature: thekzz5zxoou7zh76b3pr599mgao5eei X-HE-Tag: 1758191620-962736 X-HE-Meta: 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 rnBVmpPt M9qnEVr/FNzDHbjZqq+PCwhrBIfcY425JHvzAKq21P4r2RBGDuRCHnzFTW+cmIy5uDmh+qQeWfUbz5CJVnfu3b2vT4k4NO+pXhT0EGm4jUCracaf+nI9cGKuV6GFifRWeo0X//Q/Hf+OEtD4HaLbC6LJwCqiZ7ODNDTkfKVYx6HYD1UIqvNvb4LEn4jH0E4YtxuiJUyqD7MrQnINneYfG/wt1GJhUmxNPZDsSnSvr1uboa73ml7rpAosi6UTBM8QV4qe6CsV6KlmFWXDDScBzHdDyZjoEqGjn9coKIhPlUUjSchLbpi0b0HKujVegmLyr2eGG5BNH1afs2oFWUrmyXIAZd+bpmNqggKiGgeSP0tXB7++92ZRAfbFpXY4VM9p6U1Z3 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Sep 18, 2025 at 03:04:53PM +0530, Dev Jain wrote: > When using vmalloc with VM_ALLOW_HUGE_VMAP flag, it will set the alignment > to PMD_SIZE internally, if it deems huge mappings to be eligible. > Therefore, setting the alignment in execmem_vmalloc is redundant. Apart > from this, it also reduces the probability of allocation in case vmalloc > fails to allocate hugepages - in the fallback case, vmalloc tries to use > the original alignment and allocate basepages, which unfortunately will > again be PMD_SIZE passed over from execmem_vmalloc, thus constraining > the search for a free space in vmalloc region. > > Therefore, remove this constraint. > > Signed-off-by: Dev Jain Reviewed-by: Mike Rapoport (Microsoft) > --- > mm-selftests pass, but I am not sure if they touch execmem code, and I > have no experience with this code. > > mm/execmem.c | 3 --- > 1 file changed, 3 deletions(-) > > diff --git a/mm/execmem.c b/mm/execmem.c > index 0822305413ec..810a4ba9c924 100644 > --- a/mm/execmem.c > +++ b/mm/execmem.c > @@ -38,9 +38,6 @@ static void *execmem_vmalloc(struct execmem_range *range, size_t size, > if (kasan) > vm_flags |= VM_DEFER_KMEMLEAK; > > - if (vm_flags & VM_ALLOW_HUGE_VMAP) > - align = PMD_SIZE; > - > p = __vmalloc_node_range(size, align, start, end, gfp_flags, > pgprot, vm_flags, NUMA_NO_NODE, > __builtin_return_address(0)); > -- > 2.30.2 > -- Sincerely yours, Mike.