From: Jason Gunthorpe <jgg@ziepe.ca>
To: Jerome Glisse <jglisse@redhat.com>,
Ralph Campbell <rcampbell@nvidia.com>,
Felix.Kuehling@amd.com
Cc: Philip Yang <Philip.Yang@amd.com>,
John Hubbard <jhubbard@nvidia.com>,
amd-gfx@lists.freedesktop.org, linux-mm@kvack.org,
Jason Gunthorpe <jgg@mellanox.com>,
dri-devel@lists.freedesktop.org, Christoph Hellwig <hch@lst.de>
Subject: [PATCH v2 hmm 1/9] mm/hmm: remove pgmap checking for devmap pages
Date: Mon, 23 Mar 2020 22:14:49 -0300 [thread overview]
Message-ID: <20200324011457.2817-2-jgg@ziepe.ca> (raw)
In-Reply-To: <20200324011457.2817-1-jgg@ziepe.ca>
From: Jason Gunthorpe <jgg@mellanox.com>
The checking boils down to some racy check if the pagemap is still
available or not. Instead of checking this, rely entirely on the
notifiers, if a pagemap is destroyed then all pages that belong to it must
be removed from the tables and the notifiers triggered.
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
---
mm/hmm.c | 50 ++------------------------------------------------
1 file changed, 2 insertions(+), 48 deletions(-)
diff --git a/mm/hmm.c b/mm/hmm.c
index a491d9aaafe45d..3a2610e0713329 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -28,7 +28,6 @@
struct hmm_vma_walk {
struct hmm_range *range;
- struct dev_pagemap *pgmap;
unsigned long last;
unsigned int flags;
};
@@ -196,19 +195,8 @@ static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr,
return hmm_vma_fault(addr, end, fault, write_fault, walk);
pfn = pmd_pfn(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
- for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) {
- if (pmd_devmap(pmd)) {
- hmm_vma_walk->pgmap = get_dev_pagemap(pfn,
- hmm_vma_walk->pgmap);
- if (unlikely(!hmm_vma_walk->pgmap))
- return -EBUSY;
- }
+ for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++)
pfns[i] = hmm_device_entry_from_pfn(range, pfn) | cpu_flags;
- }
- if (hmm_vma_walk->pgmap) {
- put_dev_pagemap(hmm_vma_walk->pgmap);
- hmm_vma_walk->pgmap = NULL;
- }
hmm_vma_walk->last = end;
return 0;
}
@@ -300,15 +288,6 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
if (fault || write_fault)
goto fault;
- if (pte_devmap(pte)) {
- hmm_vma_walk->pgmap = get_dev_pagemap(pte_pfn(pte),
- hmm_vma_walk->pgmap);
- if (unlikely(!hmm_vma_walk->pgmap)) {
- pte_unmap(ptep);
- return -EBUSY;
- }
- }
-
/*
* Since each architecture defines a struct page for the zero page, just
* fall through and treat it like a normal page.
@@ -328,10 +307,6 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
return 0;
fault:
- if (hmm_vma_walk->pgmap) {
- put_dev_pagemap(hmm_vma_walk->pgmap);
- hmm_vma_walk->pgmap = NULL;
- }
pte_unmap(ptep);
/* Fault any virtual address we were asked to fault */
return hmm_vma_fault(addr, end, fault, write_fault, walk);
@@ -418,16 +393,6 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp,
return r;
}
}
- if (hmm_vma_walk->pgmap) {
- /*
- * We do put_dev_pagemap() here and not in hmm_vma_handle_pte()
- * so that we can leverage get_dev_pagemap() optimization which
- * will not re-take a reference on a pgmap if we already have
- * one.
- */
- put_dev_pagemap(hmm_vma_walk->pgmap);
- hmm_vma_walk->pgmap = NULL;
- }
pte_unmap(ptep - 1);
hmm_vma_walk->last = addr;
@@ -491,20 +456,9 @@ static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end,
}
pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
- for (i = 0; i < npages; ++i, ++pfn) {
- hmm_vma_walk->pgmap = get_dev_pagemap(pfn,
- hmm_vma_walk->pgmap);
- if (unlikely(!hmm_vma_walk->pgmap)) {
- ret = -EBUSY;
- goto out_unlock;
- }
+ for (i = 0; i < npages; ++i, ++pfn)
pfns[i] = hmm_device_entry_from_pfn(range, pfn) |
cpu_flags;
- }
- if (hmm_vma_walk->pgmap) {
- put_dev_pagemap(hmm_vma_walk->pgmap);
- hmm_vma_walk->pgmap = NULL;
- }
hmm_vma_walk->last = end;
goto out_unlock;
}
--
2.25.2
_______________________________________________
amd-gfx mailing list
amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx
next prev parent reply other threads:[~2020-03-24 8:14 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-24 1:14 [PATCH v2 hmm 0/9] Small hmm_range_fault() cleanups Jason Gunthorpe
2020-03-24 1:14 ` Jason Gunthorpe [this message]
2020-03-24 1:14 ` [PATCH v2 hmm 2/9] mm/hmm: return the fault type from hmm_pte_need_fault() Jason Gunthorpe
2020-03-24 7:27 ` Christoph Hellwig
2020-03-24 18:58 ` Jason Gunthorpe
2020-03-24 1:14 ` [PATCH v2 hmm 3/9] mm/hmm: remove unused code and tidy comments Jason Gunthorpe
2020-03-24 7:27 ` Christoph Hellwig
2020-03-24 1:14 ` [PATCH v2 hmm 4/9] mm/hmm: remove HMM_FAULT_SNAPSHOT Jason Gunthorpe
2020-03-24 7:33 ` Christoph Hellwig
2020-03-24 19:31 ` Jason Gunthorpe
2020-03-24 1:14 ` [PATCH v2 hmm 5/9] mm/hmm: remove the CONFIG_TRANSPARENT_HUGEPAGE #ifdef Jason Gunthorpe
2020-03-24 7:33 ` Christoph Hellwig
2020-03-24 1:14 ` [PATCH v2 hmm 6/9] mm/hmm: use device_private_entry_to_pfn() Jason Gunthorpe
2020-03-24 7:34 ` Christoph Hellwig
2020-03-24 1:14 ` [PATCH v2 hmm 7/9] mm/hmm: do not unconditionally set pfns when returning EBUSY Jason Gunthorpe
2020-03-24 7:37 ` Christoph Hellwig
2020-03-24 15:47 ` Jason Gunthorpe
2020-03-24 1:14 ` [PATCH v2 hmm 8/9] mm/hmm: do not set pfns when returning an error code Jason Gunthorpe
2020-03-24 7:38 ` Christoph Hellwig
2020-03-24 1:14 ` [PATCH v2 hmm 9/9] mm/hmm: return error for non-vma snapshots Jason Gunthorpe
2020-03-24 7:45 ` Christoph Hellwig
2020-03-26 21:21 ` [PATCH v2 hmm 0/9] Small hmm_range_fault() cleanups Ralph Campbell
2020-03-27 20:00 [PATCH v3 " Jason Gunthorpe
2020-03-27 20:00 ` [PATCH v2 hmm 1/9] mm/hmm: remove pgmap checking for devmap pages Jason Gunthorpe
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200324011457.2817-2-jgg@ziepe.ca \
--to=jgg@ziepe.ca \
--cc=Felix.Kuehling@amd.com \
--cc=Philip.Yang@amd.com \
--cc=amd-gfx@lists.freedesktop.org \
--cc=dri-devel@lists.freedesktop.org \
--cc=hch@lst.de \
--cc=jgg@mellanox.com \
--cc=jglisse@redhat.com \
--cc=jhubbard@nvidia.com \
--cc=linux-mm@kvack.org \
--cc=rcampbell@nvidia.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).