From: Ritesh Harjani (IBM) <ritesh.list@gmail•com>
To: Suren Baghdasaryan <surenb@google•com>, 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()
Date: Wed, 11 Feb 2026 09:25:51 +0530 [thread overview]
Message-ID: <874ino0w8o.ritesh.list@gmail.com> (raw)
In-Reply-To: <20260209220849.2126486-1-surenb@google.com>
Suren Baghdasaryan <surenb@google•com> 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 <willy@infradead•org>
> Signed-off-by: Suren Baghdasaryan <surenb@google•com>
> ---
> 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) <ritesh.list@gmail•com> # powerpc
-ritesh
prev parent reply other threads:[~2026-02-11 4:08 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-09 22:08 [PATCH 1/1] mm: replace vma_start_write() with vma_start_write_killable() Suren Baghdasaryan
2026-02-10 21:18 ` Jann Horn
2026-02-10 23:41 ` Suren Baghdasaryan
2026-02-11 3:55 ` Ritesh Harjani [this message]
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