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| author | K. Y. Srinivasan <kys@microsoft.com> | 2013-03-18 13:51:38 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-03-29 09:03:21 -0700 |
| commit | 7f4f2302a11173d0ef84bbab4b887b9b50c31dc6 (patch) | |
| tree | d5cd944948730df766a41bf54d96d8986866ba45 /drivers | |
| parent | f766dc1ea576fcdfbf2bc5638757ddbdacfb5a69 (diff) | |
| download | linux-7f4f2302a11173d0ef84bbab4b887b9b50c31dc6.tar.gz linux-7f4f2302a11173d0ef84bbab4b887b9b50c31dc6.tar.bz2 linux-7f4f2302a11173d0ef84bbab4b887b9b50c31dc6.zip | |
Drivers: hv: Notify the host of permanent hot-add failures
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>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/hv/hv_balloon.c | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c index d1b4a4624d81..4c605c70ebf9 100644 --- a/drivers/hv/hv_balloon.c +++ b/drivers/hv/hv_balloon.c @@ -590,6 +590,16 @@ static void hv_mem_hot_add(unsigned long start, unsigned long size, if (ret) { pr_info("hot_add memory failed error is %d\n", ret); + if (ret == -EEXIST) { + /* + * This error indicates that the error + * is not a transient failure. This is the + * case where the guest's physical address map + * precludes hot adding memory. Stop all further + * memory hot-add. + */ + do_hot_add = false; + } has->ha_end_pfn -= HA_CHUNK; has->covered_end_pfn -= processed_pfn; break; @@ -849,11 +859,30 @@ static void hot_add_req(struct work_struct *dummy) rg_sz = region_size; } - resp.page_count = process_hot_add(pg_start, pfn_cnt, - rg_start, rg_sz); + if (do_hot_add) + resp.page_count = process_hot_add(pg_start, pfn_cnt, + rg_start, rg_sz); #endif + /* + * The result field of the response structure has the + * following semantics: + * + * 1. If all or some pages hot-added: Guest should return success. + * + * 2. If no pages could be hot-added: + * + * If the guest returns success, then the host + * will not attempt any further hot-add operations. This + * signifies a permanent failure. + * + * If the guest returns failure, then this failure will be + * treated as a transient failure and the host may retry the + * hot-add operation after some delay. + */ if (resp.page_count > 0) resp.result = 1; + else if (!do_hot_add) + resp.result = 1; else resp.result = 0; |