From: Thomas Hellstrom <thellstrom@vmware.com>
To: <dri-devel@lists.freedesktop.org>
Cc: linux-graphics-maintainer@vmware.com,
"Thomas Hellstrom" <thellstrom@vmware.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Matthew Wilcox" <willy@infradead.org>,
"Will Deacon" <will.deacon@arm.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Rik van Riel" <riel@surriel.com>,
"Minchan Kim" <minchan@kernel.org>,
"Michal Hocko" <mhocko@suse.com>,
"Huang Ying" <ying.huang@intel.com>,
"Souptick Joarder" <jrdr.linux@gmail.com>,
"Jérôme Glisse" <jglisse@redhat.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH 1/3] mm: Allow the [page|pfn]_mkwrite callbacks to drop the mmap_sem
Date: Wed, 20 Mar 2019 16:23:13 +0100 [thread overview]
Message-ID: <20190320152315.82758-2-thellstrom@vmware.com> (raw)
In-Reply-To: <20190320152315.82758-1-thellstrom@vmware.com>
Driver fault callbacks are allowed to drop the mmap_sem when expecting
long hardware waits to avoid blocking other mm users. Allow the mkwrite
callbacks to do the same by returning early on VM_FAULT_RETRY.
In particular we want to be able to drop the mmap_sem when waiting for
a reservation object lock on a GPU buffer object. These locks may be
held while waiting for the GPU.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
---
mm/memory.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index a52663c0612d..dcd80313cf10 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2144,7 +2144,7 @@ static vm_fault_t do_page_mkwrite(struct vm_fault *vmf)
ret = vmf->vma->vm_ops->page_mkwrite(vmf);
/* Restore original flags so that caller is not surprised */
vmf->flags = old_flags;
- if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
+ if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_RETRY | VM_FAULT_NOPAGE)))
return ret;
if (unlikely(!(ret & VM_FAULT_LOCKED))) {
lock_page(page);
@@ -2419,7 +2419,7 @@ static vm_fault_t wp_pfn_shared(struct vm_fault *vmf)
pte_unmap_unlock(vmf->pte, vmf->ptl);
vmf->flags |= FAULT_FLAG_MKWRITE;
ret = vma->vm_ops->pfn_mkwrite(vmf);
- if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))
+ if (ret & (VM_FAULT_ERROR | VM_FAULT_RETRY | VM_FAULT_NOPAGE))
return ret;
return finish_mkwrite_fault(vmf);
}
@@ -2440,7 +2440,8 @@ static vm_fault_t wp_page_shared(struct vm_fault *vmf)
pte_unmap_unlock(vmf->pte, vmf->ptl);
tmp = do_page_mkwrite(vmf);
if (unlikely(!tmp || (tmp &
- (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
+ (VM_FAULT_ERROR | VM_FAULT_RETRY |
+ VM_FAULT_NOPAGE)))) {
put_page(vmf->page);
return tmp;
}
@@ -3472,7 +3473,8 @@ static vm_fault_t do_shared_fault(struct vm_fault *vmf)
unlock_page(vmf->page);
tmp = do_page_mkwrite(vmf);
if (unlikely(!tmp ||
- (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
+ (tmp & (VM_FAULT_ERROR | VM_FAULT_RETRY |
+ VM_FAULT_NOPAGE)))) {
put_page(vmf->page);
return tmp;
}
--
2.19.0.rc1
next prev parent reply other threads:[~2019-03-20 15:23 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-20 15:23 [RFC PATCH 0/3] mm modifications / helpers for emulated GPU coherent memory Thomas Hellstrom
2019-03-20 15:23 ` Thomas Hellstrom [this message]
2019-03-20 17:44 ` [RFC PATCH 1/3] mm: Allow the [page|pfn]_mkwrite callbacks to drop the mmap_sem Linus Torvalds
2019-03-20 15:23 ` [RFC PATCH 2/3] mm: Add an apply_to_pfn_range interface Thomas Hellstrom
2019-03-20 15:23 ` [RFC PATCH 3/3] mm: Add write-protect and clean utilities for address space ranges Thomas Hellstrom
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