summaryrefslogtreecommitdiff
path: root/kernel/entry
diff options
context:
space:
mode:
authorJens Axboe <axboe@kernel.dk>2020-10-17 09:25:52 -0600
committerJens Axboe <axboe@kernel.dk>2020-10-17 13:49:08 -0600
commit324bcf54c449c7b5b7024c9fa4549fbaaae1935d (patch)
tree03a41400fc0a67de4ef4f69987e39f39a53c7ba4 /kernel/entry
parent13bd691421bc191a402d2e0d3da5f248d170a632 (diff)
mm: use limited read-ahead to satisfy read
For the case where read-ahead is disabled on the file, or if the cgroup is congested, ensure that we can at least do 1 page of read-ahead to make progress on the read in an async fashion. This could potentially be larger, but it's not needed in terms of functionality, so let's error on the side of caution as larger counts of pages may run into reclaim issues (particularly if we're congested). This makes sure we're not hitting the potentially sync ->readpage() path for IO that is marked IOCB_WAITQ, which could cause us to block. It also means we'll use the same path for IO, regardless of whether or not read-ahead happens to be disabled on the lower level device. Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reported-by: Hao_Xu <haoxu@linux.alibaba.com> [axboe: updated for new ractl API] Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'kernel/entry')
0 files changed, 0 insertions, 0 deletions