| Message ID | 20210625042150.46964-1-gshan@redhat.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | mm/page_reporting: Make page reporting work on arm64 with 64KB page size | expand |
On Fri, Jun 25, 2021 at 12:21:46PM +0800, Gavin Shan wrote: > The page reporting threshold is currently equal to @pageblock_order, which > is 13 and 512MB on arm64 with 64KB base page size selected. The page > reporting won't be triggered if the freeing page can't come up with a free > area like that huge. The condition is hard to be met, especially when the > system memory becomes fragmented. > > This series intends to solve the issue by having page reporting threshold > as 5 (2MB) on arm64 with 64KB base page size. The patches are organized as: > > PATCH[1/4] Fix some coding style in __page_reporting_request(). > PATCH[2/4] Represents page reporting order with variable so that it can > be exported as module parameter. > PATCH[3/4] Allows the device driver (e.g. virtio_balloon) to specify > the page reporting order when the device info is registered. > PATCH[4/4] Specifies the page reporting order to 5, corresponding to > 2MB in size on ARM64 when 64KB base page size is used. I sent comments on v4. They still apply I think. Want me to repeat them here? > Changelog > ========= > v5: > * Restore @page_reporting_order to @pageblock_order when > device is registered in PATCH[2/4] to keep "git bisect" > friendly at least. (Alex) > v4: > * Set @page_reporting_order to MAX_ORDER. Its value is > specified by the driver or falls back to @pageblock_order > when page reporting device is registered. (Alex) > * Include "module.h" in page_reporting.c (Andrew) > v3: > * Avoid overhead introduced by function all (Alex) > * Export page reporting order as module parameter (Gavin) > v2: > * Rewrite the patches as Alex suggested (Alex) > > Gavin Shan (4): > mm/page_reporting: Fix code style in __page_reporting_request() > mm/page_reporting: Export reporting order as module parameter > mm/page_reporting: Allow driver to specify reporting > virtio_balloon: Specify page reporting order if needed > > .../admin-guide/kernel-parameters.txt | 6 +++++ > drivers/virtio/virtio_balloon.c | 17 ++++++++++++++ > include/linux/page_reporting.h | 3 +++ > mm/page_reporting.c | 22 +++++++++++++++---- > mm/page_reporting.h | 5 ++--- > 5 files changed, 46 insertions(+), 7 deletions(-) > > -- > 2.23.0
On 6/25/21 3:58 PM, Michael S. Tsirkin wrote: > On Fri, Jun 25, 2021 at 12:21:46PM +0800, Gavin Shan wrote: >> The page reporting threshold is currently equal to @pageblock_order, which >> is 13 and 512MB on arm64 with 64KB base page size selected. The page >> reporting won't be triggered if the freeing page can't come up with a free >> area like that huge. The condition is hard to be met, especially when the >> system memory becomes fragmented. >> >> This series intends to solve the issue by having page reporting threshold >> as 5 (2MB) on arm64 with 64KB base page size. The patches are organized as: >> >> PATCH[1/4] Fix some coding style in __page_reporting_request(). >> PATCH[2/4] Represents page reporting order with variable so that it can >> be exported as module parameter. >> PATCH[3/4] Allows the device driver (e.g. virtio_balloon) to specify >> the page reporting order when the device info is registered. >> PATCH[4/4] Specifies the page reporting order to 5, corresponding to >> 2MB in size on ARM64 when 64KB base page size is used. > > I sent comments on v4. They still apply I think. Want me to repeat them > here? > Thanks for your comments, Michael. I've replied to your comments through v4. There are some future work as Alex and David pointed out before: In order to remove the hack in virtio-memballoon, the VMM needs to report the page reporting order. I will keep working on this when I have spare time. Thanks, Gavin >> Changelog >> ========= >> v5: >> * Restore @page_reporting_order to @pageblock_order when >> device is registered in PATCH[2/4] to keep "git bisect" >> friendly at least. (Alex) >> v4: >> * Set @page_reporting_order to MAX_ORDER. Its value is >> specified by the driver or falls back to @pageblock_order >> when page reporting device is registered. (Alex) >> * Include "module.h" in page_reporting.c (Andrew) >> v3: >> * Avoid overhead introduced by function all (Alex) >> * Export page reporting order as module parameter (Gavin) >> v2: >> * Rewrite the patches as Alex suggested (Alex) >> >> Gavin Shan (4): >> mm/page_reporting: Fix code style in __page_reporting_request() >> mm/page_reporting: Export reporting order as module parameter >> mm/page_reporting: Allow driver to specify reporting >> virtio_balloon: Specify page reporting order if needed >> >> .../admin-guide/kernel-parameters.txt | 6 +++++ >> drivers/virtio/virtio_balloon.c | 17 ++++++++++++++ >> include/linux/page_reporting.h | 3 +++ >> mm/page_reporting.c | 22 +++++++++++++++---- >> mm/page_reporting.h | 5 ++--- >> 5 files changed, 46 insertions(+), 7 deletions(-) >> >> -- >> 2.23.0 >
On Thu, Jun 24, 2021 at 7:20 PM Gavin Shan <gshan@redhat.com> wrote: > > The page reporting threshold is currently equal to @pageblock_order, which > is 13 and 512MB on arm64 with 64KB base page size selected. The page > reporting won't be triggered if the freeing page can't come up with a free > area like that huge. The condition is hard to be met, especially when the > system memory becomes fragmented. > > This series intends to solve the issue by having page reporting threshold > as 5 (2MB) on arm64 with 64KB base page size. The patches are organized as: > > PATCH[1/4] Fix some coding style in __page_reporting_request(). > PATCH[2/4] Represents page reporting order with variable so that it can > be exported as module parameter. > PATCH[3/4] Allows the device driver (e.g. virtio_balloon) to specify > the page reporting order when the device info is registered. > PATCH[4/4] Specifies the page reporting order to 5, corresponding to > 2MB in size on ARM64 when 64KB base page size is used. > > Changelog > ========= > v5: > * Restore @page_reporting_order to @pageblock_order when > device is registered in PATCH[2/4] to keep "git bisect" > friendly at least. (Alex) These latest changes address the concerns I had. Thanks. - Alex
On 6/26/21 12:18 AM, Alexander Duyck wrote: > On Thu, Jun 24, 2021 at 7:20 PM Gavin Shan <gshan@redhat.com> wrote: >> >> The page reporting threshold is currently equal to @pageblock_order, which >> is 13 and 512MB on arm64 with 64KB base page size selected. The page >> reporting won't be triggered if the freeing page can't come up with a free >> area like that huge. The condition is hard to be met, especially when the >> system memory becomes fragmented. >> >> This series intends to solve the issue by having page reporting threshold >> as 5 (2MB) on arm64 with 64KB base page size. The patches are organized as: >> >> PATCH[1/4] Fix some coding style in __page_reporting_request(). >> PATCH[2/4] Represents page reporting order with variable so that it can >> be exported as module parameter. >> PATCH[3/4] Allows the device driver (e.g. virtio_balloon) to specify >> the page reporting order when the device info is registered. >> PATCH[4/4] Specifies the page reporting order to 5, corresponding to >> 2MB in size on ARM64 when 64KB base page size is used. >> >> Changelog >> ========= >> v5: >> * Restore @page_reporting_order to @pageblock_order when >> device is registered in PATCH[2/4] to keep "git bisect" >> friendly at least. (Alex) > > These latest changes address the concerns I had. > Thanks again for your review, Alex. However, v4 was merged and it's fine since v5 only resolves 'git-bisect' friendly issue on PATCH[v4 2/4]. Thanks, Gavin
The page reporting threshold is currently equal to @pageblock_order, which is 13 and 512MB on arm64 with 64KB base page size selected. The page reporting won't be triggered if the freeing page can't come up with a free area like that huge. The condition is hard to be met, especially when the system memory becomes fragmented. This series intends to solve the issue by having page reporting threshold as 5 (2MB) on arm64 with 64KB base page size. The patches are organized as: PATCH[1/4] Fix some coding style in __page_reporting_request(). PATCH[2/4] Represents page reporting order with variable so that it can be exported as module parameter. PATCH[3/4] Allows the device driver (e.g. virtio_balloon) to specify the page reporting order when the device info is registered. PATCH[4/4] Specifies the page reporting order to 5, corresponding to 2MB in size on ARM64 when 64KB base page size is used. Changelog ========= v5: * Restore @page_reporting_order to @pageblock_order when device is registered in PATCH[2/4] to keep "git bisect" friendly at least. (Alex) v4: * Set @page_reporting_order to MAX_ORDER. Its value is specified by the driver or falls back to @pageblock_order when page reporting device is registered. (Alex) * Include "module.h" in page_reporting.c (Andrew) v3: * Avoid overhead introduced by function all (Alex) * Export page reporting order as module parameter (Gavin) v2: * Rewrite the patches as Alex suggested (Alex) Gavin Shan (4): mm/page_reporting: Fix code style in __page_reporting_request() mm/page_reporting: Export reporting order as module parameter mm/page_reporting: Allow driver to specify reporting virtio_balloon: Specify page reporting order if needed .../admin-guide/kernel-parameters.txt | 6 +++++ drivers/virtio/virtio_balloon.c | 17 ++++++++++++++ include/linux/page_reporting.h | 3 +++ mm/page_reporting.c | 22 +++++++++++++++---- mm/page_reporting.h | 5 ++--- 5 files changed, 46 insertions(+), 7 deletions(-)