From: Huang Ying
During fork, the page table need to be copied from parent to child. A
PMD swap mapping need to be copied too and the swap reference count
need to be increased.
When the huge swap cluster has been split already, we need to split
the PMD swap mapping and fallback to PTE copying
From: Huang Ying
When madvise_free() found a PMD swap mapping, if only part of the huge
swap cluster is operated on, the PMD swap mapping will be split and
fallback to PTE swap mapping processing. Otherwise, if all huge swap
cluster is operated on, free_swap_and_cache() will be called to
From: Huang Ying
When a PMD swap mapping is removed from a huge swap cluster, for
example, unmap a memory range mapped with PMD swap mapping, etc,
free_swap_and_cache() will be called to decrease the reference count
to the huge swap cluster. free_swap_and_cache() may also free or
split the huge
From: Huang Ying
Previously, the PMD swap operations are only enabled for
CONFIG_ARCH_ENABLE_THP_MIGRATION. Because they are only used by the
THP migration support. We will support PMD swap mapping to the huge
swap cluster and swapin the THP as a whole. That will be enabled via
From: Huang Ying
Previously, during swapout, all PMD page mapping will be split and
replaced with PTE swap mapping. And when clearing the SWAP_HAS_CACHE
flag for the huge swap cluster in swapcache_free_cluster(), the huge
swap cluster will be split. Now, during swapout, the PMD page mapping
From: Huang Ying
It's unreasonable to optimize swapping for THP without basic swapping
support. And this will cause build errors when THP_SWAP functions are
defined in swapfile.c and called elsewhere.
The comments are fixed too to reflect the latest progress.
Signed-off-by: "Huang,
From: Huang Ying
Hi, Andrew, could you help me to check whether the overall design is
reasonable?
Hi, Hugh, Shaohua, Minchan and Rik, could you help me to review the
swap part of the patchset? Especially [02/21], [03/21], [04/21],
[05/21], [06/21], [07/21], [08/21], [09/21], [10/21], [11/21
=y
>> CONFIG_STACKPROTECTOR=y
>> CONFIG_STACKPROTECTOR_STRONG=y
>> CONFIG_CC_HAS_SANE_STACKPROTECTOR=y
>
> so you're testing the "no overhead" case to the "worst overhead" case.
Do you have interest in some other comparison?
Best Regards,
Huang, Ying
Daniel Jordan writes:
> On Tue, Jun 12, 2018 at 09:23:19AM +0800, Huang, Ying wrote:
>> Daniel Jordan writes:
>> >> +#else
>> >> +static inline int __swap_duplicate_cluster(swp_entry_t *entry,
>> >
>> > This doesn't need inline.
>
"Huang, Ying" writes:
>> On Wed, May 23, 2018 at 04:26:07PM +0800, Huang, Ying wrote:
>>> @@ -3516,11 +3512,39 @@ static int __swap_duplicate(swp_entry_t entry,
>>> unsigned char usage)
>>
>> Two comments about this part of __swap_duplicate as long
*/
> - err = swapcache_prepare(entry);
> + err = swapcache_prepare(entry, false);
> if (err == -EEXIST) {
> radix_tree_preload_end();
> /*
Thanks for pointing this out! Will change in the next ve
Daniel Jordan writes:
> On Wed, May 23, 2018 at 04:26:04PM +0800, Huang, Ying wrote:
>> And for all, Any comment is welcome!
>>
>> This patchset is based on the 2018-05-18 head of mmotm/master.
>
> Trying to review this and it doesn't apply to mmotm-2018-05-18
Naoya Horiguchi writes:
> On Wed, May 23, 2018 at 04:26:04PM +0800, Huang, Ying wrote:
>> From: Huang Ying
>>
>> Hi, Andrew, could you help me to check whether the overall design is
>> reasonable?
>>
>> Hi, Hugh, Shaohua, Minchan and Rik, could you he
From: Huang Ying
To take better advantage of general huge page copying optimization,
the target subpage address will be passed to hugetlb_cow(), then
copy_user_huge_page(). So we will use both target subpage address and
huge page size aligned address in hugetlb_cow(). To distinguish
between
From: Huang Ying
Huge page helps to reduce TLB miss rate, but it has higher cache
footprint, sometimes this may cause some issue. For example, when
copying huge page on x86_64 platform, the cache footprint is 4M. But
on a Xeon E5 v3 2699 CPU, there are 18 cores, 36 threads, and only 45M
LLC
From: Huang Ying
This is to take better advantage of the general huge page copying
optimization. Where, the target subpage will be copied last to avoid
the cache lines of target subpage to be evicted when copying other
subpages. This works better if the address of the target subpage is
From: Huang Ying
In commit c79b57e462b5d ("mm: hugetlb: clear target sub-page last when
clearing huge page"), to keep the cache lines of the target subpage
hot, the order to clear the subpages in the huge page in
clear_huge_page() is changed to clearing the subpage which is furthes
From: Huang Ying
Huge page helps to reduce TLB miss rate, but it has higher cache
footprint, sometimes this may cause some issue. For example, when
copying huge page on x86_64 platform, the cache footprint is 4M. But
on a Xeon E5 v3 2699 CPU, there are 18 cores, 36 threads, and only 45M
LLC
From: Huang Ying
To support to swapin the THP as a whole, we need to create PMD swap
mapping during swapout, and maintain PMD swap mapping count. This
patch implements the support to increase the PMD swap mapping
count (for swapout, fork, etc.) and set SWAP_HAS_CACHE flag (for
swapin, etc
From: Huang Ying
Previously, the PMD swap operations are only enabled for
CONFIG_ARCH_ENABLE_THP_MIGRATION. Because they are only used by the
THP migration support. We will support PMD swap mapping to the huge
swap cluster and swapin the THP as a whole. That will be enabled via
From: Huang Ying
When a PMD swap mapping is removed from a huge swap cluster, for
example, unmap a memory range mapped with PMD swap mapping, etc,
free_swap_and_cache() will be called to decrease the reference count
to the huge swap cluster. free_swap_and_cache() may also free or
split the huge
From: Huang Ying
It's unreasonable to optimize swapping for THP without basic swapping
support. And this will cause build errors when THP_SWAP functions are
defined in swapfile.c and called elsewhere.
The comments are fixed too to reflect the latest progress.
Signed-off-by: "Huang,
From: Huang Ying
To swapin a THP as a whole, we need to read a huge swap cluster from
the swap device. This patch revised the __read_swap_cache_async() and
its callers and callees to support this. If __read_swap_cache_async()
find the swap cluster of the specified swap entry is huge, it will
From: Huang Ying
A huge PMD need to be split when zap a part of the PMD mapping etc.
If the PMD mapping is a swap mapping, we need to split it too. This
patch implemented the support for this. This is similar as splitting
the PMD page mapping, except we need to decrease the PMD swap mapping
From: Huang Ying
With this patch, when page fault handler find a PMD swap mapping, it
will swap in a THP as a whole. This avoids the overhead of
splitting/collapsing before/after the THP swapping. And improves the
swap performance greatly for reduced page fault count etc
From: Huang Ying
Swapin a THP as a whole isn't desirable at some situations. For
example, for random access pattern, swapin a THP as a whole will
inflate the reading greatly. So a sysfs interface:
/sys/kernel/mm/transparent_hugepage/swapin_enabled is added to
configure it. Three optio
From: Huang Ying
During swapoff, for a huge swap cluster, we need to allocate a THP,
read its contents into the THP and unuse the PMD and PTE swap mappings
to it. If failed to allocate a THP, the huge swap cluster will be
split.
During unuse, if it is found that the swap cluster mapped by a
From: Huang Ying
Previously the huge swap cluster will be split after the THP is
swapout. Now, to support to swapin the THP as a whole, the huge swap
cluster will not be split after the THP is reclaimed. So in memcg, we
need to move the swap account for PMD swap mappings in the process's
From: Huang Ying
During MADV_WILLNEED, for a PMD swap mapping, if THP swapin is enabled
for the VMA, the whole swap cluster will be swapin. Otherwise, the
huge swap cluster and the PMD swap mapping will be split and fallback
to PTE swap mapping.
Signed-off-by: "Huang, Ying"
Cc:
From: Huang Ying
Previously, to reclaim MADV_FREE THP, the THP will be split firstly,
then reclaim each sub-pages. This wastes cycles to split THP and
unmap and free each sub-pages, and split THP even if it has been
written since MADV_FREE. We have to do this because MADV_FREE THP
reclaiming
From: Huang Ying
Original code is only for PMD migration entry, it is revised to
support PMD swap mapping.
Signed-off-by: "Huang, Ying"
Cc: "Kirill A. Shutemov"
Cc: Andrea Arcangeli
Cc: Michal Hocko
Cc: Johannes Weiner
Cc: Shaohua Li
Cc: Hugh Dickins
Cc: Minchan Kim
From: Huang Ying
During mincore(), for PMD swap mapping, swap cache will be looked up.
If the resulting page isn't compound page, the PMD swap mapping will
be split and fallback to PTE swap mapping processing.
Signed-off-by: "Huang, Ying"
Cc: "Kirill A. Shutemov"
From: Huang Ying
This is the final step of the THP swapin support. When reclaiming a
anonymous THP, after allocating the huge swap cluster and add the THP
into swap cache, the PMD page mapping will be changed to the mapping
to the swap space. Previously, the PMD page mapping will be split
From: Huang Ying
When splitting a THP in swap cache or failing to allocate a THP when
swapin a huge swap cluster, the huge swap cluster will be split. In
addition to clear the huge flag of the swap cluster, the PMD swap
mapping count recorded in cluster_count() will be set to 0. But we
will
From: Huang Ying
For a PMD swap mapping, zap_huge_pmd() will clear the PMD and call
free_swap_and_cache() to decrease the swap reference count and maybe
free or split the huge swap cluster and the THP in swap cache.
Signed-off-by: "Huang, Ying"
Cc: "Kirill A. Shutemov"
From: Huang Ying
During fork, the page table need to be copied from parent to child. A
PMD swap mapping need to be copied too and the swap reference count
need to be increased.
When the huge swap cluster has been split already, we need to split
the PMD swap mapping and fallback to PTE copying
From: Huang Ying
2 new /proc/vmstat fields are added, "thp_swapin" and
"thp_swapin_fallback" to count swapin a THP from swap device as a
whole and fallback to normal page swapin.
Signed-off-by: "Huang, Ying"
Cc: "Kirill A. Shutemov"
Cc: Andrea Arcangel
From: Huang Ying
When madvise_free() found a PMD swap mapping, if only part of the huge
swap cluster is operated on, the PMD swap mapping will be split and
fallback to PTE swap mapping processing. Otherwise, if all huge swap
cluster is operated on, free_swap_and_cache() will be called to
From: Huang Ying
Previously, during swapout, all PMD page mapping will be split and
replaced with PTE swap mapping. And when clearing the SWAP_HAS_CACHE
flag for the huge swap cluster in swapcache_free_cluster(), the huge
swap cluster will be split. Now, during swapout, the PMD page mapping
From: Huang Ying
Hi, Andrew, could you help me to check whether the overall design is
reasonable?
Hi, Hugh, Shaohua, Minchan and Rik, could you help me to review the
swap part of the patchset? Especially [02/21], [03/21], [04/21],
[05/21], [06/21], [07/21], [08/21], [09/21], [10/21], [11/21
Mike Kravetz writes:
> On 05/17/2018 11:24 PM, Michal Hocko wrote:
>> On Fri 18-05-18 11:03:16, Huang, Ying wrote:
>> [...]
>>> The patch is a generic optimization which should benefit quite some
>>> workloads, not for a specific use case. To demonstrate the per
Hi, Michal,
Michal Hocko writes:
> On Fri 18-05-18 11:03:16, Huang, Ying wrote:
> [...]
>> The patch is a generic optimization which should benefit quite some
>> workloads, not for a specific use case. To demonstrate the performance
>> benefit of the patch, we tested it
From: Huang Ying
Huge page helps to reduce TLB miss rate, but it has higher cache
footprint, sometimes this may cause some issue. For example, when
copying huge page on x86_64 platform, the cache footprint is 4M. But
on a Xeon E5 v3 2699 CPU, there are 18 cores, 36 threads, and only 45M
LLC
From: Huang Ying
This is to take better advantage of general huge page clearing
optimization (c79b57e462b5d, "mm: hugetlb: clear target sub-page last
when clearing huge page") for hugetlbfs. In the general optimization
patch, the sub-page to access will be cleared last to avoid the c
From: Huang Ying
This is to take better advantage of huge page clearing
optimization (c79b57e462b5d, "mm: hugetlb: clear target sub-page last
when clearing huge page"). Which will clear to access sub-page last
to avoid the cache lines of to access sub-page to be evicted when
clearing
From: Huang Ying
It's unreasonable to optimize swapping for THP without basic swapping
support. And this will cause build errors when THP_SWAP functions are
defined in swapfile.c and called elsewhere.
The comments are fixed too to reflect the latest progress.
Signed-off-by: "Huang,
From: Huang Ying
Previously, during swapout, all PMD page mapping will be split and
replaced with PTE swap mapping. And when clearing the SWAP_HAS_CACHE
flag for the huge swap cluster in swapcache_free_cluster(), the huge
swap cluster will be split. Now, during swapout, the PMD page mapping
From: Huang Ying
A huge PMD need to be split when zap a part of the PMD mapping etc.
If the PMD mapping is a swap mapping, we need to split it too. This
patch implemented the support for this. This is similar as splitting
the PMD page mapping, except we need to decrease the PMD swap mapping
From: Huang Ying
When a PMD swap mapping is removed from a huge swap cluster, for
example, unmap a memory range mapped with PMD swap mapping, etc,
free_swap_and_cache() will be called to decrease the reference count
to the huge swap cluster. free_swap_and_cache() may also free or
split the huge
From: Huang Ying
When splitting a THP in swap cache or failing to allocate a THP when
swapin a huge swap cluster, the huge swap cluster will be split. In
addition to clear the huge flag of the swap cluster, the PMD swap
mapping count recorded in cluster_count() will be set to 0. But we
will
From: Huang Ying
With this patch, when page fault handler find a PMD swap mapping, it
will swap in a THP as a whole. This avoids the overhead of
splitting/collapsing before/after the THP swapping. And improves the
swap performance greatly for reduced page fault count etc
From: Huang Ying
During swapoff, for a huge swap cluster, we need to allocate a THP,
read its contents into the THP and unuse the PMD and PTE swap mappings
to it. If failed to allocate a THP, the huge swap cluster will be
split.
During unuse, if it is found that the swap cluster mapped by a
From: Huang Ying
To swapin a THP as a whole, we need to read a huge swap cluster from
the swap device. This patch revised the __read_swap_cache_async() and
its callers and callees to support this. If __read_swap_cache_async()
find the swap cluster of the specified swap entry is huge, it will
From: Huang Ying
Swapin a THP as a whole isn't desirable at some situations. For
example, for random access pattern, swapin a THP as a whole will
inflate the reading greatly. So a sysfs interface:
/sys/kernel/mm/transparent_hugepage/swapin_enabled is added to
configure it. Three optio
From: Huang Ying
For a PMD swap mapping, zap_huge_pmd() will clear the PMD and call
free_swap_and_cache() to decrease the swap reference count and maybe
free or split the huge swap cluster and the THP in swap cache.
Signed-off-by: "Huang, Ying"
Cc: "Kirill A. Shutemov"
From: Huang Ying
Original code is only for PMD migration entry, it is revised to
support PMD swap mapping.
Signed-off-by: "Huang, Ying"
Cc: "Kirill A. Shutemov"
Cc: Andrea Arcangeli
Cc: Michal Hocko
Cc: Johannes Weiner
Cc: Shaohua Li
Cc: Hugh Dickins
Cc: Minchan Kim
From: Huang Ying
During MADV_WILLNEED, for a PMD swap mapping, if THP swapin is enabled
for the VMA, the whole swap cluster will be swapin. Otherwise, the
huge swap cluster and the PMD swap mapping will be split and fallback
to PTE swap mapping.
Signed-off-by: "Huang, Ying"
Cc:
From: Huang Ying
Previously, to reclaim MADV_FREE THP, the THP will be split firstly,
then reclaim each sub-pages. This wastes cycles to split THP and
unmap and free each sub-pages, and split THP even if it has been
written since MADV_FREE. We have to do this because MADV_FREE THP
reclaiming
From: Huang Ying
When madvise_free() found a PMD swap mapping, if only part of the huge
swap cluster is operated on, the PMD swap mapping will be split and
fallback to PTE swap mapping processing. Otherwise, if all huge swap
cluster is operated on, free_swap_and_cache() will be called to
From: Huang Ying
During fork, the page table need to be copied from parent to child. A
PMD swap mapping need to be copied too and the swap reference count
need to be increased.
When the huge swap cluster has been split already, we need to split
the PMD swap mapping and fallback to PTE copying
From: Huang Ying
Previously the huge swap cluster will be split after the THP is
swapout. Now, to support to swapin the THP as a whole, the huge swap
cluster will not be split after the THP is reclaimed. So in memcg, we
need to move the swap account for PMD swap mappings in the process's
From: Huang Ying
This is the final step of the THP swapin support. When reclaiming a
anonymous THP, after allocating the huge swap cluster and add the THP
into swap cache, the PMD page mapping will be changed to the mapping
to the swap space. Previously, the PMD page mapping will be split
From: Huang Ying
During mincore(), for PMD swap mapping, swap cache will be looked up.
If the resulting page isn't compound page, the PMD swap mapping will
be split and fallback to PTE swap mapping processing.
Signed-off-by: "Huang, Ying"
Cc: "Kirill A. Shutemov"
From: Huang Ying
Previously, the PMD swap operations are only enabled for
CONFIG_ARCH_ENABLE_THP_MIGRATION. Because they are only used by the
THP migration support. We will support PMD swap mapping to the huge
swap cluster and swapin the THP as a whole. That will be enabled via
From: Huang Ying
To support to swapin the THP as a whole, we need to create PMD swap
mapping during swapout, and maintain PMD swap mapping count. This
patch implements the support to increase the PMD swap mapping
count (for swapout, fork, etc.) and set SWAP_HAS_CACHE flag (for
swapin, etc
From: Huang Ying
Hi, Andrew, could you help me to check whether the overall design is
reasonable?
Hi, Hugh, Shaohua, Minchan and Rik, could you help me to review the
swap part of the patchset? Especially [02/21], [03/21], [04/21],
[05/21], [06/21], [07/21], [08/21], [09/21], [10/21], [11/21
From: Huang Ying
2 new /proc/vmstat fields are added, "thp_swapin" and
"thp_swapin_fallback" to count swapin a THP from swap device as a
whole and fallback to normal page swapin.
Signed-off-by: "Huang, Ying"
Cc: "Kirill A. Shutemov"
Cc: Andrea Arcangel
From: Huang Ying
Add document for newly added thp_swpout, thp_swpout_fallback fields in
/proc/vmstat.
Signed-off-by: "Huang, Ying"
Cc: "Kirill A. Shutemov"
Cc: Andrea Arcangeli
Cc: Johannes Weiner
---
Documentation/vm/transhuge.rst | 9 +
1 file changed, 9 inser
From: Huang Ying
In ab676b7d6fbf ("pagemap: do not leak physical addresses to
non-privileged userspace"), the /proc/PID/pagemap is restricted to be
readable only by CAP_SYS_ADMIN to address some security issue. In
1c90308e7a77 ("pagemap: hide physical addresses from non-privileg
From: Huang Ying
mmap_sem will be read locked when calling follow_pmd_mask(). But this
cannot prevent PMD from being changed for all cases when PTL is
unlocked, for example, from pmd_trans_huge() to pmd_none() via
MADV_DONTNEED. So it is possible for the pmd_present() check in
follow_pmd_mask
Randy Dunlap writes:
> On 04/16/18 19:02, Huang, Ying wrote:
>> From: Huang Ying
>>
>> 2 new /proc/vmstat fields are added, "thp_swapin" and
>> "thp_swapin_fallback" to count swapin a THP from swap device as a
>> whole and fallback to n
Randy Dunlap writes:
> On 04/16/18 19:02, Huang, Ying wrote:
>> From: Huang Ying
>>
>> A huge PMD need to be split when zap a part of the PMD mapping etc.
>> If the PMD mapping is a swap mapping, we need to split it too. This
>> patch implemented the supp
From: Huang Ying
To support to swapin the THP as a whole, we need to create PMD swap
mapping during swapout, and maintain PMD swap mapping count. This
patch implements the support to increase the PMD swap mapping
count (for swapout, fork, etc.) and set SWAP_HAS_CACHE flag (for
swapin, etc
From: Huang Ying
Previously, during swapout, all PMD page mapping will be split and
replaced with PTE swap mapping. And when clearing the SWAP_HAS_CACHE
flag for the huge swap cluster in swapcache_free_cluster(), the huge
swap cluster will be split. Now, during swapout, the PMD page mapping
From: Huang Ying
When a PMD swap mapping is removed from a huge swap cluster, for
example, unmap a memory range mapped with PMD swap mapping, etc,
free_swap_and_cache() will be called to decrease the reference count
to the huge swap cluster. free_swap_and_cache() may also free or
split the huge
From: Huang Ying
To swapin a THP as a whole, we need to read a huge swap cluster from
the swap device. This patch revised the __read_swap_cache_async() and
its callee to support this. If __read_swap_cache_async() find the
swap cluster of the specified swap entry is huge, it will try to
From: Huang Ying
Previously the huge swap cluster will be split after the THP is
swapout. Now, to support to swapin the THP as a whole, the huge swap
cluster will not be split after the THP is reclaimed. So in memcg, we
need to move the swap account for PMD swap mappings in the process's
From: Huang Ying
Swapin a THP as a whole isn't desirable at some situations. For
example, for random access pattern, swapin a THP as a whole will
inflate the reading greatly. So a sysfs interface:
/sys/kernel/mm/transparent_hugepage/swapin_enabled is added to
configure it. Three optio
From: Huang Ying
During MADV_WILLNEED, for a PMD swap mapping, if THP swapin is enabled
for the VMA, the whole swap cluster will be swapin. Otherwise, the
huge swap cluster and the PMD swap mapping will be split and fallback
to PTE swap mapping.
Signed-off-by: "Huang, Ying"
Cc:
From: Huang Ying
During fork, the page table need to be copied from parent to child. A
PMD swap mapping need to be copied too and the swap reference count
need to be increased.
When the huge swap cluster has been split already, we need to split
the PMD swap mapping and fallback to PTE copying
From: Huang Ying
This is the final step of the THP swapin support. When reclaiming a
anonymous THP, after allocating the huge swap cluster and add the THP
into swap cache, the PMD page mapping will be changed to the mapping
to the swap space. Previously, the PMD page mapping will be split
From: Huang Ying
During swapoff, for a huge swap cluster, we need to allocate a THP,
read its contents into the THP and unuse the PMD and PTE swap mappings
to it. If failed to allocate a THP, the huge swap cluster will be
split.
During unuse, if it is found that the swap cluster mapped by a
From: Huang Ying
During mincore(), for PMD swap mapping, swap cache will be looked up.
If the resulting page isn't compound page, the PMD swap mapping will
be split and fallback to PTE swap mapping processing.
Signed-off-by: "Huang, Ying"
Cc: "Kirill A. Shutemov"
From: Huang Ying
Previously, to reclaim MADV_FREE THP, the THP will be split firstly,
then reclaim each sub-pages. This wastes cycles to split THP and
unmap and free each sub-pages, and split THP even if it has been
written since MADV_FREE. We have to do this because MADV_FREE THP
reclaiming
From: Huang Ying
For a PMD swap mapping, zap_huge_pmd() will clear the PMD and call
free_swap_and_cache() to decrease the swap reference count and maybe
free or split the huge swap cluster and the THP in swap cache.
Signed-off-by: "Huang, Ying"
Cc: "Kirill A. Shutemov"
From: Huang Ying
Original code is only for PMD migration entry, it is revised to
support PMD swap mapping.
Signed-off-by: "Huang, Ying"
Cc: "Kirill A. Shutemov"
Cc: Andrea Arcangeli
Cc: Michal Hocko
Cc: Johannes Weiner
Cc: Shaohua Li
Cc: Hugh Dickins
Cc: Minchan Kim
From: Huang Ying
When madvise_free() found a PMD swap mapping, if only part of the huge
swap cluster is operated on, the PMD swap mapping will be split and
fallback to PTE swap mapping processing. Otherwise, if all huge swap
cluster is operated on, free_swap_and_cache() will be called to
From: Huang Ying
2 new /proc/vmstat fields are added, "thp_swapin" and
"thp_swapin_fallback" to count swapin a THP from swap device as a
whole and fallback to normal page swapin.
Signed-off-by: "Huang, Ying"
Cc: "Kirill A. Shutemov"
Cc: Andrea Arcangel
From: Huang Ying
With this patch, when page fault handler find a PMD swap mapping, it
will swap in a THP as a whole. This avoids the overhead of
splitting/collapsing before/after the THP swapping. And improves the
swap performance greatly for reduced page fault count etc
From: Huang Ying
A huge PMD need to be split when zap a part of the PMD mapping etc.
If the PMD mapping is a swap mapping, we need to split it too. This
patch implemented the support for this. This is similar as splitting
the PMD page mapping, except we need to decrease the PMD swap mapping
From: Huang Ying
When splitting a THP in swap cache or failing to allocate a THP when
swapin a huge swap cluster, the huge swap cluster will be split. In
addition to clear the huge flag of the swap cluster, the PMD swap
mapping count recorded in cluster_count() will be set to 0. But we
will
From: Huang Ying
It's unreasonable to optimize swapping for THP without basic swapping
support. And this will cause build errors when THP_SWAP functions are
defined in swapfile.c and called elsewhere.
The comments are fixed too to reflect the latest progress.
Signed-off-by: "Huang,
From: Huang Ying
Previously, the PMD swap operations are only enabled for
CONFIG_ARCH_ENABLE_THP_MIGRATION. Because they are only used by the
THP migration support. We will support PMD swap mapping to the huge
swap cluster and swapin the THP as a whole. That will be enabled via
From: Huang Ying
Hi, Andrew, could you help me to check whether the overall design is
reasonable?
Hi, Hugh, Shaohua, Minchan and Rik, could you help me to review the
swap part of the patchset? Especially [02/21], [03/21], [04/21],
[05/21], [06/21], [07/21], [08/21], [09/21], [10/21], [11/21
"Kirill A. Shutemov" writes:
> On Tue, Apr 10, 2018 at 08:57:19AM +0800, Huang, Ying wrote:
>> >> the swap offset reported doesn't
>> >> reflect this. And in the loop to report information of each sub-page,
>> >> the swap offset isn
Hi, Andrew,
"Huang, Ying" writes:
> From: Huang Ying
>
> The swap offset reported by /proc//pagemap may be not correct for
> PMD migration entry. If addr passed into pagemap_range() isn't
> aligned with PMD start address, the swap offset reported doesn't
Andrew Morton writes:
> On Sun, 8 Apr 2018 11:37:37 +0800 "Huang, Ying" wrote:
>
>> From: Huang Ying
>>
>> The swap offset reported by /proc//pagemap may be not correct for
>> PMD migration entry. If addr passed into pagemap_range() isn't
>
&
From: Huang Ying
The swap offset reported by /proc//pagemap may be not correct for
PMD migration entry. If addr passed into pagemap_range() isn't
aligned with PMD start address, the swap offset reported doesn't
reflect this. And in the loop to report information of each sub-page
On Wed, Apr 4, 2018 at 11:02 PM, Zi Yan wrote:
> On 3 Apr 2018, at 23:22, Huang, Ying wrote:
>
>> From: Huang Ying
>>
>> mmap_sem will be read locked when calling follow_pmd_mask(). But this
>> cannot prevent PMD from being changed for all cases when PTL is
From: Huang Ying
mmap_sem will be read locked when calling follow_pmd_mask(). But this
cannot prevent PMD from being changed for all cases when PTL is
unlocked, for example, from pmd_trans_huge() to pmd_none() via
MADV_DONTNEED. So it is possible for the pmd_present() check in
follow_pmd_mask
601 - 700 of 1489 matches
Mail list logo
