From: Oleg Nesterov <oleg@redhat.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Andy Lutomirski <luto@amacapital.net>,
Andrew Morton <akpm@linux-foundation.org>,
Denys Vlasenko <dvlasenk@redhat.com>,
Brian Gerst <brgerst@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Waiman Long <Waiman.Long@hp.com>
Subject: why do we need vmalloc_sync_all?
Date: Sat, 13 Jun 2015 20:58:28 +0200 [thread overview]
Message-ID: <20150613185828.GA32376@redhat.com> (raw)
In-Reply-To: <1434188955-31397-1-git-send-email-mingo@kernel.org>
I didn't read v2 yet, but I'd like to ask a question.
Why do we need vmalloc_sync_all()?
It has a single caller, register_die_notifier() which calls it without
any explanation. IMO, this needs a comment at least.
I am not sure I understand the changelog in 101f12af correctly, but
at first glance vmalloc_sync_all() is no longer needed at least on x86,
do_page_fault() no longer does notify_die(DIE_PAGE_FAULT). And btw
DIE_PAGE_FAULT has no users. DIE_MNI too...
Perhaps we can simply kill it on x86?
As for other architectures I am not sure. arch/tile implements
vmalloc_sync_all() and uses notify_die() in do_page_fault().
And in any case register_die_notifier()->vmalloc_sync() looks strange.
If (say) arch/tile needs this to fix the problem with modules, perhaps
it should do vmalloc_sync_all() in do_init_module() paths?
Oleg.
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next prev parent reply other threads:[~2015-06-13 18:59 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-13 9:49 [PATCH 00/12, v2] x86/mm: Implement lockless pgd_alloc()/pgd_free() Ingo Molnar
2015-06-13 9:49 ` [PATCH 01/12] x86/mm/pat: Don't free PGD entries on memory unmap Ingo Molnar
2015-06-13 9:49 ` [PATCH 02/12] x86/mm/hotplug: Remove pgd_list use from the memory hotplug code Ingo Molnar
2015-06-13 19:24 ` Oleg Nesterov
2015-06-14 7:36 ` Ingo Molnar
2015-06-14 19:24 ` Oleg Nesterov
2015-06-14 19:38 ` Oleg Nesterov
2015-06-15 0:40 ` Paul E. McKenney
2015-06-15 20:33 ` Ingo Molnar
2015-06-13 9:49 ` [PATCH 03/12] x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() Ingo Molnar
2015-06-13 9:49 ` [PATCH 04/12] x86/mm/hotplug: Simplify sync_global_pgds() Ingo Molnar
2015-06-13 9:49 ` [PATCH 05/12] mm: Introduce arch_pgd_init_late() Ingo Molnar
2015-06-13 9:49 ` [PATCH 06/12] x86/mm: Enable and use the arch_pgd_init_late() method Ingo Molnar
2015-06-13 9:49 ` [PATCH 07/12] x86/virt/guest/xen: Remove use of pgd_list from the Xen guest code Ingo Molnar
2015-06-14 8:26 ` Ingo Molnar
2015-06-15 9:05 ` Ian Campbell
2015-06-15 10:30 ` David Vrabel
2015-06-15 20:35 ` Ingo Molnar
2015-06-16 14:15 ` David Vrabel
2015-06-16 14:19 ` Boris Ostrovsky
2015-06-16 14:27 ` David Vrabel
2015-06-13 9:49 ` [PATCH 08/12] x86/mm: Remove pgd_list use from vmalloc_sync_all() Ingo Molnar
2015-06-13 9:49 ` [PATCH 09/12] x86/mm/pat/32: Remove pgd_list use from the PAT code Ingo Molnar
2015-06-13 9:49 ` [PATCH 10/12] x86/mm: Make pgd_alloc()/pgd_free() lockless Ingo Molnar
2015-06-13 9:49 ` [PATCH 11/12] x86/mm: Remove pgd_list leftovers Ingo Molnar
2015-06-13 9:49 ` [PATCH 12/12] x86/mm: Simplify pgd_alloc() Ingo Molnar
2015-06-13 18:58 ` Oleg Nesterov [this message]
2015-06-14 7:59 ` why do we need vmalloc_sync_all? Ingo Molnar
2015-06-14 20:06 ` Oleg Nesterov
2015-06-15 2:47 ` Andi Kleen
2015-06-15 2:57 ` Andy Lutomirski
2015-06-15 20:28 ` Ingo Molnar
2015-06-15 20:48 ` Andy Lutomirski
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