Messages in this thread | | | Subject | Re: [RFC PATCH] mm: introduce kv[mz]alloc helpers | From | David Hildenbrand <> | Date | Thu, 8 Dec 2016 14:00:20 +0100 |
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Am 08.12.2016 um 11:33 schrieb Michal Hocko: > From: Michal Hocko <mhocko@suse.com> > > Using kmalloc with the vmalloc fallback for larger allocations is a > common pattern in the kernel code. Yet we do not have any common helper > for that and so users have invented their own helpers. Some of them are > really creative when doing so. Let's just add kv[mz]alloc and make sure > it is implemented properly. This implementation makes sure to not make > a large memory pressure for > PAGE_SZE requests (__GFP_NORETRY) and also > to not warn about allocation failures. This also rules out the OOM > killer as the vmalloc is a more approapriate fallback than a disruptive > user visible action. > > This patch also changes some existing users and removes helpers which > are specific for them. In some cases this is not possible (e.g. > ext4_kvmalloc, libcfs_kvzalloc, __aa_kvmalloc) because those seems to be > broken and require GFP_NO{FS,IO} context which is not vmalloc compatible > in general (note that the page table allocation is GFP_KERNEL). Those > need to be fixed separately. > > apparmor has already claimed kv[mz]alloc so remove those and use > __aa_kvmalloc instead to prevent from the naming clashes. > > Cc: Paolo Bonzini <pbonzini@redhat.com> > Cc: Mike Snitzer <snitzer@redhat.com> > Cc: dm-devel@redhat.com > Cc: "Michael S. Tsirkin" <mst@redhat.com> > Cc: "Theodore Ts'o" <tytso@mit.edu> > Cc: kvm@vger.kernel.org > Cc: linux-ext4@vger.kernel.org > Cc: linux-f2fs-devel@lists.sourceforge.net > Cc: linux-security-module@vger.kernel.org > Signed-off-by: Michal Hocko <mhocko@suse.com>
I remember yet another similar user in arch/s390/kvm/kvm-s390.c -> kvm_s390_set_skeys()
... keys = kmalloc_array(args->count, sizeof(uint8_t), GFP_KERNEL | __GFP_NOWARN); if (!keys) vmalloc(sizeof(uint8_t) * args->count); ...
would kvmalloc_array make sense? (it would even make the code here less error prone and better to read)
--
David
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