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| author | David Vrabel <david.vrabel@citrix.com> | 2013-09-19 17:14:53 +0100 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2013-09-24 16:22:27 -0400 |
| commit | 24f69373e212d4356268fbb1d01c5735423c300d (patch) | |
| tree | 2d8b679328228141ebbcd85f792828b90f44cf54 /drivers/xen/balloon.c | |
| parent | a945928ea2709bc0e8e8165d33aed855a0110279 (diff) | |
| download | linux-24f69373e212d4356268fbb1d01c5735423c300d.tar.gz | |
xen/balloon: don't alloc page while non-preemptible
get_balloon_scratch_page() disables preemption so we cannot call alloc_page() in between get/put_balloon_scratch_page(). Shuffle bits around in decrease_reservation() to avoid this. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/xen/balloon.c')
| -rw-r--r-- | drivers/xen/balloon.c | 23 |
1 files changed, 11 insertions, 12 deletions
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index a50c6e3a7cc4..b232908a6192 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -398,8 +398,6 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) if (nr_pages > ARRAY_SIZE(frame_list)) nr_pages = ARRAY_SIZE(frame_list); - scratch_page = get_balloon_scratch_page(); - for (i = 0; i < nr_pages; i++) { page = alloc_page(gfp); if (page == NULL) { @@ -413,6 +411,12 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) scrub_page(page); + /* + * Ballooned out frames are effectively replaced with + * a scratch frame. Ensure direct mappings and the + * p2m are consistent. + */ + scratch_page = get_balloon_scratch_page(); #ifdef CONFIG_XEN_HAVE_PVMMU if (xen_pv_domain() && !PageHighMem(page)) { ret = HYPERVISOR_update_va_mapping( @@ -422,24 +426,19 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) BUG_ON(ret); } #endif - } - - /* Ensure that ballooned highmem pages don't have kmaps. */ - kmap_flush_unused(); - flush_tlb_all(); - - /* No more mappings: invalidate P2M and add to balloon. */ - for (i = 0; i < nr_pages; i++) { - pfn = mfn_to_pfn(frame_list[i]); if (!xen_feature(XENFEAT_auto_translated_physmap)) { unsigned long p; p = page_to_pfn(scratch_page); __set_phys_to_machine(pfn, pfn_to_mfn(p)); } + put_balloon_scratch_page(); + balloon_append(pfn_to_page(pfn)); } - put_balloon_scratch_page(); + /* Ensure that ballooned highmem pages don't have kmaps. */ + kmap_flush_unused(); + flush_tlb_all(); set_xen_guest_handle(reservation.extent_start, frame_list); reservation.nr_extents = nr_pages; |