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path: root/drivers/hv/hv_balloon.c
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* Drivers: hv: balloon: Initialize last_post_time on startupAlex Ng2017-08-161-0/+1
| | | | | | | | | | | | | | | | When left uninitialized, this sometimes fails the following check in post_status(): if (!time_after(now, (last_post_time + HZ))) { return; } This causes unnecessary delays in reporting memory pressure to host after booting up. Signed-off-by: Alex Ng <alexng@messages.microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Show the max dynamic memory assignedAlex Ng2017-08-161-2/+2
| | | | | | | | | | Previously we were only showing max number of pages. We should make it more clear that this value is the max amount of dynamic memory that the Hyper-V host is willing to assign to this guest. Signed-off-by: Alex Ng <alexng@messages.microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Correctly update onlined page countAlex Ng2017-08-161-4/+3
| | | | | | | | | | | | Previously, num_pages_onlined was updated using value from memory online notifier. This is incorrect because they assume that all hot-added pages are online, even though we only online the amount that's backed by the host. We should update num_pages_onlined only when the balloon driver marks a page as online. Signed-off-by: Alex Ng <alexng@messages.microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* vmbus: remove useless return'sStephen Hemminger2017-03-171-2/+0
| | | | | | | | No need for empty return at end of void function Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: add a fall through comment to hv_memory_notifier()Vitaly Kuznetsov2017-01-311-0/+1
| | | | | | | | | | | | Coverity scan gives a warning when there is fall through in a switch without a comment. This fall through is intentional as ol_waitevent needs to be completed to unblock hv_mem_hot_add() allowing it to process next requests regardless of the result of if we were able to online this block. Reported-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Fix info request to show max page countAlex Ng2016-11-071-2/+7
| | | | | | | | | | Balloon driver was only printing the size of the info blob and not the actual content. This fixes it so that the info blob (max page count as configured in Hyper-V) is printed out. Signed-off-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Add logging for dynamic memory operationsAlex Ng2016-11-071-3/+28
| | | | | | | | | Added logging to help troubleshoot common ballooning, hot add, and versioning issues. Signed-off-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Disable hot add when CONFIG_MEMORY_HOTPLUG is not setAlex Ng2016-11-071-0/+4
| | | | | | | | | | | If the guest does not support memory hotplugging, it should respond to the host with zero pages added and successful result code. This signals to the host that hotplugging is not supported and the host will avoid sending future hot-add requests. Signed-off-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Use available memory value in pressure reportAlex Ng2016-08-311-8/+5
| | | | | | | | | Reports for available memory should use the si_mem_available() value. The previous freeram value does not include available page cache memory. Signed-off-by: Alex Ng <alexng@messages.microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: replace ha_region_mutex with spinlockVitaly Kuznetsov2016-08-311-45/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | | lockdep reports possible circular locking dependency when udev is used for memory onlining: systemd-udevd/3996 is trying to acquire lock: ((memory_chain).rwsem){++++.+}, at: [<ffffffff810d137e>] __blocking_notifier_call_chain+0x4e/0xc0 but task is already holding lock: (&dm_device.ha_region_mutex){+.+.+.}, at: [<ffffffffa015382e>] hv_memory_notifier+0x5e/0xc0 [hv_balloon] ... which is probably a false positive because we take and release ha_region_mutex from memory notifier chain depending on the arg. No real deadlocks were reported so far (though I'm not really sure about preemptible kernels...) but we don't really need to hold the mutex for so long. We use it to protect ha_region_list (and its members) and the num_pages_onlined counter. None of these operations require us to sleep and nothing is slow, switch to using spinlock with interrupts disabled. While on it, replace list_for_each -> list_for_each_entry as we actually need entries in all these cases, drop meaningless list_empty() checks. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: don't wait for ol_waitevent when memhp_auto_online is ↵Vitaly Kuznetsov2016-08-311-6/+9
| | | | | | | | | | | | enabled With the recently introduced in-kernel memory onlining (MEMORY_HOTPLUG_DEFAULT_ONLINE) these is no point in waiting for pages to come online in the driver and we can get rid of the waiting. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: account for gaps in hot add regionsVitaly Kuznetsov2016-08-311-37/+94
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I'm observing the following hot add requests from the WS2012 host: hot_add_req: start_pfn = 0x108200 count = 330752 hot_add_req: start_pfn = 0x158e00 count = 193536 hot_add_req: start_pfn = 0x188400 count = 239616 As the host doesn't specify hot add regions we're trying to create 128Mb-aligned region covering the first request, we create the 0x108000 - 0x160000 region and we add 0x108000 - 0x158e00 memory. The second request passes the pfn_covered() check, we enlarge the region to 0x108000 - 0x190000 and add 0x158e00 - 0x188200 memory. The problem emerges with the third request as it starts at 0x188400 so there is a 0x200 gap which is not covered. As the end of our region is 0x190000 now it again passes the pfn_covered() check were we just adjust the covered_end_pfn and make it 0x188400 instead of 0x188200 which means that we'll try to online 0x188200-0x188400 pages but these pages were never assigned to us and we crash. We can't react to such requests by creating new hot add regions as it may happen that the whole suggested range falls into the previously identified 128Mb-aligned area so we'll end up adding nothing or create intersecting regions and our current logic doesn't allow that. Instead, create a list of such 'gaps' and check for them in the page online callback. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: keep track of where ha_region startsVitaly Kuznetsov2016-08-311-2/+5
| | | | | | | | | | | | | | | | | | | Windows 2012 (non-R2) does not specify hot add region in hot add requests and the logic in hot_add_req() is trying to find a 128Mb-aligned region covering the request. It may also happen that host's requests are not 128Mb aligned and the created ha_region will start before the first specified PFN. We can't online these non-present pages but we don't remember the real start of the region. This is a regression introduced by the commit 5abbbb75d733 ("Drivers: hv: hv_balloon: don't lose memory when onlining order is not natural"). While the idea of keeping the 'moving window' was wrong (as there is no guarantee that hot add requests come ordered) we should still keep track of covered_start_pfn. This is not a revert, the logic is different. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: reset host_specified_ha_regionVitaly Kuznetsov2016-05-011-0/+1
| | | | | | | | | | | We set host_specified_ha_region = true on certain request but this is a global state which stays 'true' forever. We need to reset it when we receive a request where ha_region is not specified. I did not see any real issues, the bug was found by code inspection. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: don't crash when memory is added in non-sorted orderVitaly Kuznetsov2016-05-011-2/+2
| | | | | | | | | | | | | | | When we iterate through all HA regions in handle_pg_range() we have an assumption that all these regions are sorted in the list and the 'start_pfn >= has->end_pfn' check is enough to find the proper region. Unfortunately it's not the case with WS2016 where host can hot-add regions in a different order. We end up modifying the wrong HA region and crashing later on pages online. Modify the check to make sure we found the region we were searching for while iterating. Fix the same check in pfn_covered() as well. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Enable dynamic memory protocol negotiation with ↵Alex Ng2015-08-041-6/+20
| | | | | | | | | | | Windows 10 hosts Support Win10 protocol for Dynamic Memory. Thia patch allows guests on Win10 hosts to hot-add memory even when dynamic memory is not enabled on the guest. Signed-off-by: Alex Ng <alexng@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: check if ha_region_mutex was acquired in ↵Vitaly Kuznetsov2015-06-011-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | MEM_CANCEL_ONLINE case Memory notifiers are being executed in a sequential order and when one of them fails returning something different from NOTIFY_OK the remainder of the notification chain is not being executed. When a memory block is being onlined in online_pages() we do memory_notify(MEM_GOING_ONLINE, ) and if one of the notifiers in the chain fails we end up doing memory_notify(MEM_CANCEL_ONLINE, ) so it is possible for a notifier to see MEM_CANCEL_ONLINE without seeing the corresponding MEM_GOING_ONLINE event. E.g. when CONFIG_KASAN is enabled the kasan_mem_notifier() is being used to prevent memory hotplug, it returns NOTIFY_BAD for all MEM_GOING_ONLINE events. As kasan_mem_notifier() comes before the hv_memory_notifier() in the notification chain we don't see the MEM_GOING_ONLINE event and we do not take the ha_region_mutex. We, however, see the MEM_CANCEL_ONLINE event and unconditionally try to release the lock, the following is observed: [ 110.850927] ===================================== [ 110.850927] [ BUG: bad unlock balance detected! ] [ 110.850927] 4.1.0-rc3_bugxxxxxxx_test_xxxx #595 Not tainted [ 110.850927] ------------------------------------- [ 110.850927] systemd-udevd/920 is trying to release lock (&dm_device.ha_region_mutex) at: [ 110.850927] [<ffffffff81acda0e>] mutex_unlock+0xe/0x10 [ 110.850927] but there are no more locks to release! At the same time we can have the ha_region_mutex taken when we get the MEM_CANCEL_ONLINE event in case one of the memory notifiers after the hv_memory_notifier() in the notification chain failed so we need to add the mutex_is_locked() check. In case of MEM_ONLINE we are always supposed to have the mutex locked. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: hv_balloon: correctly handle num_pages>INT_MAX caseVitaly Kuznetsov2015-04-031-6/+7
| | | | | | | | | | | | | | | | | balloon_wrk.num_pages is __u32 and it comes from host in struct dm_balloon where it is also __u32. We, however, use 'int' in balloon_up() and in case we happen to receive num_pages>INT_MAX request we'll end up allocating zero pages as 'num_pages < alloc_unit' check in alloc_balloon_pages() will pass. Change num_pages type to unsigned int. In real life ballooning request come with num_pages in [512, 32768] range so this is more a future-proof/cleanup. Reported-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: hv_balloon: correctly handle val.freeram<num_pages caseVitaly Kuznetsov2015-04-031-1/+1
| | | | | | | | | | | | | | | | | 'Drivers: hv: hv_balloon: refuse to balloon below the floor' fix does not correctly handle the case when val.freeram < num_pages as val.freeram is __kernel_ulong_t and the 'val.freeram - num_pages' value will be a huge positive value instead of being negative. Usually host doesn't ask us to balloon more than val.freeram but in case he have a memory hog started after we post the last pressure report we can get into troubles. Suggested-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: hv_balloon: survive ballooning request with num_pages=0Vitaly Kuznetsov2015-04-031-13/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... and simplify alloc_balloon_pages() interface by removing redundant alloc_error from it. If we happen to enter balloon_up() with balloon_wrk.num_pages = 0 we will enter infinite 'while (!done)' loop as alloc_balloon_pages() will be always returning 0 and not setting alloc_error. We will also be sending a meaningless message to the host on every iteration. The 'alloc_unit == 1 && alloc_error -> num_ballooned == 0' change and alloc_error elimination requires a special comment. We do alloc_balloon_pages() with 2 different alloc_unit values and there are 4 different alloc_balloon_pages() results, let's check them all. alloc_unit = 512: 1) num_ballooned = 0, alloc_error = 0: we do 'alloc_unit=1' and retry pre- and post-patch. 2) num_ballooned > 0, alloc_error = 0: we check 'num_ballooned == num_pages' and act accordingly, pre- and post-patch. 3) num_ballooned > 0, alloc_error > 0: we report this chunk and remain within the loop, no changes here. 4) num_ballooned = 0, alloc_error > 0: we do 'alloc_unit=1' and retry pre- and post-patch. alloc_unit = 1: 1) num_ballooned = 0, alloc_error = 0: this can happen in two cases: when we passed 'num_pages=0' to alloc_balloon_pages() or when there was no space in bl_resp to place a single response. The second option is not possible as bl_resp is of PAGE_SIZE size and single response 'union dm_mem_page_range' is 8 bytes, but the first one is (in theory, I think that Hyper-V host never places such requests). Pre-patch code loops forever, post-patch code sends a reply with more_pages = 0 and finishes. 2) num_ballooned > 0, alloc_error = 0: we ran out of space in bl_resp, we report partial success and remain within the loop, no changes pre- and post-patch. 3) num_ballooned > 0, alloc_error > 0: pre-patch code finishes, post-patch code does one more try and if there is no progress (we finish with 'num_ballooned = 0') we finish. So we try a bit harder with this patch. 4) num_ballooned = 0, alloc_error > 0: both pre- and post-patch code enter 'more_pages = 0' branch and finish. So this patch has two real effects: 1) We reply with an empty response to 'num_pages=0' request. 2) We try a bit harder on alloc_unit=1 allocations (and reply with an empty tail reply in case we fail). An empty reply should be supported by host as we were able to send it even with pre-patch code when we were not able to allocate a single page. Suggested-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: hv_balloon: eliminate jumps in piecewiese linear floor functionVitaly Kuznetsov2015-04-031-4/+4
| | | | | | | | | | | | | | | | | | | | | Commit 79208c57da53 ("Drivers: hv: hv_balloon: Make adjustments in computing the floor") was inacurate as it introduced a jump in our piecewiese linear 'floor' function: At 2048MB we have: Left limit: 104 + 2048/8 = 360 Right limit: 256 + 2048/16 = 384 (so the right value is 232) We now have to make an adjustment at 8192 boundary: 232 + 8192/16 = 744 512 + 8192/32 = 768 (so the right value is 488) Suggested-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: hv_balloon: do not online pages in offline blocksVitaly Kuznetsov2015-04-031-1/+11
| | | | | | | | | | | | | | | | | | | Currently we add memory in 128Mb blocks but the request from host can be aligned differently. In such case we add a partially backed block and when this block goes online we skip onlining pages which are not backed (hv_online_page() callback serves this purpose). When we receive next request for the same host add region we online pages which were not backed before with hv_bring_pgs_online(). However, we don't check if the the block in question was onlined and online this tail unconditionally. This is bad as we avoid all online_pages() logic: these pages are not accounted, we don't send notifications (and hv_balloon is not the only receiver of them),... And, first of all, nobody asked as to online these pages. Solve the issue by checking if the last previously backed page was onlined and onlining the tail only in case it was. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: hv_balloon: don't lose memory when onlining order is not naturalVitaly Kuznetsov2015-03-251-10/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Memory blocks can be onlined in random order. When this order is not natural some memory pages are not onlined because of the redundant check in hv_online_page(). Here is a real world scenario: 1) Host tries to hot-add the following (process_hot_add): pg_start=rg_start=0x48000, pfn_cnt=111616, rg_size=262144 2) This results in adding 4 memory blocks: [ 109.057866] init_memory_mapping: [mem 0x48000000-0x4fffffff] [ 114.102698] init_memory_mapping: [mem 0x50000000-0x57ffffff] [ 119.168039] init_memory_mapping: [mem 0x58000000-0x5fffffff] [ 124.233053] init_memory_mapping: [mem 0x60000000-0x67ffffff] The last one is incomplete but we have special has->covered_end_pfn counter to avoid onlining non-backed frames and hv_bring_pgs_online() function to bring them online later on. 3) Now we have 4 offline memory blocks: /sys/devices/system/memory/memory9-12 $ for f in /sys/devices/system/memory/memory*/state; do echo $f `cat $f`; done | grep -v onlin /sys/devices/system/memory/memory10/state offline /sys/devices/system/memory/memory11/state offline /sys/devices/system/memory/memory12/state offline /sys/devices/system/memory/memory9/state offline 4) We bring them online in non-natural order: $grep MemTotal /proc/meminfo MemTotal: 966348 kB $echo online > /sys/devices/system/memory/memory12/state && grep MemTotal /proc/meminfo MemTotal: 1019596 kB $echo online > /sys/devices/system/memory/memory11/state && grep MemTotal /proc/meminfo MemTotal: 1150668 kB $echo online > /sys/devices/system/memory/memory9/state && grep MemTotal /proc/meminfo MemTotal: 1150668 kB As you can see memory9 block gives us zero additional memory. We can also observe a huge discrepancy between host- and guest-reported memory sizes. The root cause of the issue is the redundant pg >= covered_start_pfn check (and covered_start_pfn advancing) in hv_online_page(). When upper memory block in being onlined before the lower one (memory12 and memory11 in the above case) we advance the covered_start_pfn pointer and all memory9 pages do not pass the check. If the assumption that host always gives us requests in sequential order and pg_start always equals rg_start when the first request for the new HA region is received (that's the case in my testing) is correct than we can get rid of covered_start_pfn and pg >= start_pfn check in hv_online_page() is sufficient. The current char-next branch is broken and this patch fixes the bug. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: hv_balloon: keep locks balanced on add_memory() failureVitaly Kuznetsov2015-03-251-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | When add_memory() fails the following BUG is observed: [ 743.646107] hv_balloon: hot_add memory failed error is -17 [ 743.679973] [ 743.680930] ===================================== [ 743.680930] [ BUG: bad unlock balance detected! ] [ 743.680930] 3.19.0-rc5_bug1131426+ #552 Not tainted [ 743.680930] ------------------------------------- [ 743.680930] kworker/0:2/255 is trying to release lock (&dm_device.ha_region_mutex) at: [ 743.680930] [<ffffffff81aae5fe>] mutex_unlock+0xe/0x10 [ 743.680930] but there are no more locks to release! This happens as we don't acquire ha_region_mutex and hot_add_req() expects us to as it does unconditional mutex_unlock(). Acquire the lock on the error path. The current char-next branch is broken and this patch fixes the bug. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: hv_balloon: refuse to balloon below the floorVitaly Kuznetsov2015-03-011-0/+11
| | | | | | | | | | When host asks us to balloon up we need to be sure we're not committing suicide by overballooning. Use already existent 'floor' metric as our lowest possible value for free ram. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: hv_balloon: report offline pages as being usedVitaly Kuznetsov2015-03-011-9/+24
| | | | | | | | | | | | | When hot-added memory pages are not brought online or when some memory blocks are sent offline the subsequent ballooning process kills the guest with OOM killer. This happens as we don't report these pages as neither used nor free and apparently host algorithm considers them as being unused. Keep track of all online/offline operations and report all currently offline pages as being used so host won't try to balloon them out. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: hv_balloon: eliminate the trylock path in ↵Vitaly Kuznetsov2015-03-011-29/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | acquire/release_region_mutex When many memory regions are being added and automatically onlined the following lockup is sometimes observed: INFO: task udevd:1872 blocked for more than 120 seconds. ... Call Trace: [<ffffffff816ec0bc>] schedule_timeout+0x22c/0x350 [<ffffffff816eb98f>] wait_for_common+0x10f/0x160 [<ffffffff81067650>] ? default_wake_function+0x0/0x20 [<ffffffff816eb9fd>] wait_for_completion+0x1d/0x20 [<ffffffff8144cb9c>] hv_memory_notifier+0xdc/0x120 [<ffffffff816f298c>] notifier_call_chain+0x4c/0x70 ... When several memory blocks are going online simultaneously we got several hv_memory_notifier() trying to acquire the ha_region_mutex. When this mutex is being held by hot_add_req() all these competing acquire_region_mutex() do mutex_trylock, fail, and queue themselves into wait_for_completion(..). However when we do complete() from release_region_mutex() only one of them wakes up. This could be solved by changing complete() -> complete_all() memory onlining can be delayed as well, in that case we can still get several hv_memory_notifier() runners at the same time trying to grab the mutex. Only one of them will succeed and the others will hang for forever as complete() is not being called. We don't see this issue often because we have 5sec onlining timeout in hv_mem_hot_add() and usually all udev events arrive in this time frame. Get rid of the trylock path, waiting on the mutex is supposed to provide the required serialization. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* hv: hv_balloon: match var type to return type of wait_for_completionNicholas Mc Guire2015-03-011-1/+2
| | | | | | | | | return type of wait_for_completion_timeout is unsigned long not int, this patch changes the type of t from int to unsigned long. Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: hv_balloon: Don't post pressure status from interrupt contextK. Y. Srinivasan2015-01-251-7/+4
| | | | | | | | | | | | | | We currently release memory (balloon down) in the interrupt context and we also post memory status while releasing memory. Rather than posting the status in the interrupt context, wakeup the status posting thread to post the status. This will address the inconsistent lock state that Sitsofe Wheeler <sitsofe@gmail.com> reported: http://lkml.iu.edu/hypermail/linux/kernel/1411.1/00075.html Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reported-by: Sitsofe Wheeler <sitsofe@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: hv_balloon: Fix a locking bug in the balloon driverK. Y. Srinivasan2015-01-251-5/+63
| | | | | | | | | | | | We support memory hot-add in the Hyper-V balloon driver by hot adding an appropriately sized and aligned region and controlling the on-lining of pages within that region based on the pages that the host wants us to online. We do this because the granularity and alignment requirements in Linux are different from what Windows expects. The state to manage the onlining of pages needs to be correctly protected. Fix this bug. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: hv_balloon: Make adjustments in computing the floorK. Y. Srinivasan2015-01-251-4/+5
| | | | | | | | | | | Make adjustments in computing the balloon floor. The current computation of the balloon floor was not appropriate for virtual machines with more than 10 GB of assigned memory - we would get into situations where the host would agressively balloon down the guest and leave the guest in an unusable state. This patch fixes the issue by raising the floor. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* hv: hv_balloon: avoid memory leak on alloc_error of 2MB memory blockDexuan Cui2014-11-261-3/+7
| | | | | | | | | | If num_ballooned is not 0, we shouldn't neglect the already-partially-allocated 2MB memory block(s). Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Ensure pressure reports are posted regularlyK. Y. Srinivasan2014-05-031-3/+26
| | | | | | | | | | | The current code posts periodic memory pressure status from a dedicated thread. Under some conditions, especially when we are releasing a lot of memory into the guest, we may not send timely pressure reports back to the host. Fix this issue by reporting pressure in all contexts that can be active in this driver. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: Ballon: Make pressure posting thread sleep interruptiblyK. Y. Srinivasan2014-02-151-1/+2
| | | | | | | | The non-interruptible sleep of the memory pressure posting thread results in higher reported load average. Make this sleep interruptible. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: remove HV_DRV_VERSIONOlaf Hering2013-08-021-1/+0
| | | | | | | | | | | | | | | | | Remove HV_DRV_VERSION, it has no meaning for upstream drivers. Initially it was supposed to show the "Linux Integration Services" version, now it is not in sync anymore with the out-of-tree drivers available from the MSFT website. The only place where a version string is still required is the KVP command "IntegrationServicesVersion" which is handled by tools/hv/hv_kvp_daemon.c. To satisfy such KVP request from the host pass the current string to the daemon during KVP userland registration. Signed-off-by: Olaf Hering <olaf@aepfle.de> Acked-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge 3.11-rc3 into char-misc-next.Greg Kroah-Hartman2013-07-291-8/+13
|\ | | | | | | | | | | | | This resolves a merge issue with: drivers/misc/mei/init.c Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * Drivers: hv: balloon: Do not post pressure status if interruptedK. Y. Srinivasan2013-07-161-0/+8
| | | | | | | | | | | | | | | | | | | | When we are posting pressure status, we may get interrupted and handle the un-balloon operation. In this case just don't post the status as we know the pressure status is stale. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: Stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * Drivers: hv: balloon: Fix a bug in the hot-add codeK. Y. Srinivasan2013-07-161-8/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | As we hot-add 128 MB chunks of memory, we wait to ensure that the memory is onlined before attempting to hot-add the next chunk. If the udev rule for memory hot-add is not executed within the allowed time, we would rollback the state and abort further hot-add. Since the hot-add has succeeded and the only failure is that the memory is not onlined within the allowed time, we should not be rolling back the state. Fix this bug. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Cc: Stable <stable@vger.kernel.org> Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | Drivers: hv: balloon: Initialize the transaction ID just before sending the ↵K. Y. Srinivasan2013-07-261-2/+2
|/ | | | | | | | | | | packet Each message sent from the guest carries with it a transaction ID. Assign the transaction ID just before putting the message on the VMBUS. This would help in debugging on the host side. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: Notify the host of permanent hot-add failuresK. Y. Srinivasan2013-03-291-2/+31
| | | | | | | | | | | | | If memory hot-add fails with the error -EEXIST, then this is a permanent failure. Notify the host of this information, so the host will not attempt hot-add again. If the failure were a transient failure, host will attempt a hot-add after some delay. In this version of the patch, I have added some additional comments to clarify how the host treats different failure conditions. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Support 2M page allocations for ballooningK. Y. Srinivasan2013-03-291-2/+16
| | | | | | | | | | | | | | | | | | | | On Hyper-V it will be very efficient to use 2M allocations in the guest as this makes the ballooning protocol with the host that much more efficient. Hyper-V uses page ranges (start pfn : number of pages) to specify memory being moved around and with 2M pages this encoding can be very efficient. However, when memory is returned to the guest, the host does not guarantee any granularity. To deal with this issue, split the page soon after a successful 2M allocation so that this memory can potentially be freed as 4K pages. If 2M allocations fail, we revert to 4K allocations. In this version of the patch, based on the feedback from Michal Hocko <mhocko@suse.cz>, I have added some additional commentary to the patch description. Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Permit Linux to specify hot-add alignment requirementsK. Y. Srinivasan2013-03-291-2/+15
| | | | | | | | | | Some Windows hosts permit the guest to specify memory hot-add alignment requirements (if any). Linux currently requires a 128MB alignment on memory segments that can be hot-added. Specify this alignment requirement to the host. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: make local functions staticWei Yongjun2013-03-251-2/+2
| | | | | | | local functions that could be static. Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Implement hot-add functionalityK. Y. Srinivasan2013-03-151-21/+387
| | | | | | | | | | | | | | | Implement the memory hot-add functionality. With this, Linux guests can fully participate in the Dynamic Memory protocol implemented in the Windows hosts. In this version of the patch, based Olaf Herring's feedback, I have gotten rid of the module level dependency on MEMORY_HOTPLUG. Instead the code within the driver that depends on MEMORY_HOTPLUG has the appropriate compilation switches. This would allow this driver to support pure ballooning in cases where the kernel does not support memory hotplug. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Make the balloon driver not unloadableK. Y. Srinivasan2013-03-151-7/+0
| | | | | | | | | | | | | The balloon driver is stateful. For instance, it needs to keep track of pages that have been ballooned out to properly post pressure reports. This state cannot be re-constructed if the driver were to be unloaded and subsequently loaded. Furthermore, as we support memory hot-add as part of this driver, this driver becomes even more stateful and this state cannot be re-created. Make the balloon driver unloadable to deal with this issue. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Execute hot-add code in a separate contextK. Y. Srinivasan2013-03-151-18/+23
| | | | | | | | | | | Execute the hot-add operation in a separate work context. This allows us to decouple the pressure reporting activity from the "hot-add" activity. Testing has shown that this makes the guest more responsive to hot add requests. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Execute balloon inflation in a separate contextK. Y. Srinivasan2013-03-151-10/+24
| | | | | | | | | | | Execute the balloon inflation operation in a separate work context. This allows us to decouple the pressure reporting activity from the ballooning activity. Testing has shown that this decoupling makes the guest more reponsive. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Do not request completion notificationK. Y. Srinivasan2013-03-151-4/+2
| | | | | | | There is no need to request completion notification; get rid of it. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Prevent the host from ballooning the guest too lowK. Y. Srinivasan2013-02-081-1/+34
| | | | | | | | | Based on the amount of memory being managed set a floor on how low the guest can be ballooned. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Drivers: hv: balloon: Add a parameter to delay pressure reportingK. Y. Srinivasan2013-02-081-2/+11
| | | | | | | | | | | Delay reporting memory pressure by a specified amount of time. This addresses the problem where the host may take memory balancing decisions based on incorrect memory pressure data that will be posted as soon as the balloon driver is loaded. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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