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Tue, 10 Feb 2026 20:08:29 -0800 (PST) Received: from dw-tp ([49.205.216.49]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-8249e7d5e7csm568794b3a.33.2026.02.10.20.08.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Feb 2026 20:08:29 -0800 (PST) From: Ritesh Harjani (IBM) To: Suren Baghdasaryan , akpm@linux-foundation.org Cc: willy@infradead.org, david@kernel.org, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net, ying.huang@linux.alibaba.com, apopple@nvidia.com, lorenzo.stoakes@oracle.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, vbabka@suse.cz, jannh@google.com, rppt@kernel.org, mhocko@suse.com, pfalcato@suse.de, kees@kernel.org, maddy@linux.ibm.com, npiggin@gmail.com, mpe@ellerman.id.au, chleroy@kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, surenb@google.com Subject: Re: [PATCH 1/1] mm: replace vma_start_write() with vma_start_write_killable() In-Reply-To: <20260209220849.2126486-1-surenb@google.com> Date: Wed, 11 Feb 2026 09:25:51 +0530 Message-ID: <874ino0w8o.ritesh.list@gmail.com> References: <20260209220849.2126486-1-surenb@google.com> X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 1F0C24000E X-Stat-Signature: kogznugd3b645wuyut3f3p9od5fzefnf X-Rspam-User: X-HE-Tag: 1770782910-956562 X-HE-Meta: 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 wbaCaHji 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 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: Suren Baghdasaryan writes: > Now that we have vma_start_write_killable() we can replace most of the > vma_start_write() calls with it, improving reaction time to the kill > signal. > > There are several places which are left untouched by this patch: > > 1. free_pgtables() because function should free page tables even if a > fatal signal is pending. > > 2. userfaultd code, where some paths calling vma_start_write() can > handle EINTR and some can't without a deeper code refactoring. > > 3. vm_flags_{set|mod|clear} require refactoring that involves moving > vma_start_write() out of these functions and replacing it with > vma_assert_write_locked(), then callers of these functions should > lock the vma themselves using vma_start_write_killable() whenever > possible. > > Suggested-by: Matthew Wilcox > Signed-off-by: Suren Baghdasaryan > --- > arch/powerpc/kvm/book3s_hv_uvmem.c | 5 +- > include/linux/mempolicy.h | 5 +- > mm/khugepaged.c | 5 +- > mm/madvise.c | 4 +- > mm/memory.c | 2 + > mm/mempolicy.c | 23 ++++++-- > mm/mlock.c | 20 +++++-- > mm/mprotect.c | 4 +- > mm/mremap.c | 4 +- > mm/pagewalk.c | 20 +++++-- > mm/vma.c | 94 +++++++++++++++++++++--------- > mm/vma_exec.c | 6 +- > 12 files changed, 139 insertions(+), 53 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c > index 7cf9310de0ec..69750edcf8d5 100644 > --- a/arch/powerpc/kvm/book3s_hv_uvmem.c > +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c > @@ -410,7 +410,10 @@ static int kvmppc_memslot_page_merge(struct kvm *kvm, > ret = H_STATE; > break; > } > - vma_start_write(vma); > + if (vma_start_write_killable(vma)) { > + ret = H_STATE; > + break; > + } > /* Copy vm_flags to avoid partial modifications in ksm_madvise */ > vm_flags = vma->vm_flags; > ret = ksm_madvise(vma, vma->vm_start, vma->vm_end, The above change w.r.t. powerpc error handling in function kvmppc_memslot_page_merge() looks good to me. Please feel free to add: Reviewed-by: Ritesh Harjani (IBM) # powerpc -ritesh