diff options
| author | Christoph Hellwig <hch@lst.de> | 2020-09-25 06:19:19 +0200 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2020-09-25 06:19:19 +0200 |
| commit | 8c1c6c7588b2faf9dd45fb3cfb7497fd09bbfe7c (patch) | |
| tree | 50a7ddcfd7e7b1a7e4fb656bb88a036dbcff4bd6 /mm/page_isolation.c | |
| parent | 38225f2ef2f4263fc65acae63fdd4e8489c9ffcf (diff) | |
| parent | 171d4ff79f965c1f164705ef0aaea102a6ad238b (diff) | |
Merge branch 'master' of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into dma-mapping-for-next
Pull in the latest 5.9 tree for the commit to revert the
V4L2_FLAG_MEMORY_NON_CONSISTENT uapi addition.
Diffstat (limited to 'mm/page_isolation.c')
| -rw-r--r-- | mm/page_isolation.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/page_isolation.c b/mm/page_isolation.c index 242c03121d731..63a3db10a8c0c 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -170,6 +170,14 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages) * pageblocks we may have modified and return -EBUSY to caller. This * prevents two threads from simultaneously working on overlapping ranges. * + * Please note that there is no strong synchronization with the page allocator + * either. Pages might be freed while their page blocks are marked ISOLATED. + * In some cases pages might still end up on pcp lists and that would allow + * for their allocation even when they are in fact isolated already. Depending + * on how strong of a guarantee the caller needs drain_all_pages might be needed + * (e.g. __offline_pages will need to call it after check for isolated range for + * a next retry). + * * Return: the number of isolated pageblocks on success and -EBUSY if any part * of range cannot be isolated. */ |