diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2012-06-15 17:43:36 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-06-16 09:10:44 +0200 |
| commit | 7a5bfb66b07f22d2429db776da7bb8b57bfb5cff (patch) | |
| tree | aa6a419726f99052171f05b004db45692fef3315 | |
| parent | uprobes: Rework register_for_each_vma() to make it O(n) (diff) | |
| download | linux-7a5bfb66b07f22d2429db776da7bb8b57bfb5cff.tar.xz linux-7a5bfb66b07f22d2429db776da7bb8b57bfb5cff.zip | |
uprobes: Change build_map_info() to try kmalloc(GFP_NOWAIT) first
build_map_info() doesn't allocate the memory under i_mmap_mutex
to avoid the deadlock with page reclaim. But it can try
GFP_NOWAIT first, it should work in the likely case and thus we
almost never need the pre-alloc-and-retry path.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Link: http://lkml.kernel.org/r/20120615154336.GA9588@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | kernel/events/uprobes.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 4e0db3496d70..897417dbca8e 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -761,6 +761,16 @@ build_map_info(struct address_space *mapping, loff_t offset, bool is_register) if (!valid_vma(vma, is_register)) continue; + if (!prev && !more) { + /* + * Needs GFP_NOWAIT to avoid i_mmap_mutex recursion through + * reclaim. This is optimistic, no harm done if it fails. + */ + prev = kmalloc(sizeof(struct map_info), + GFP_NOWAIT | __GFP_NOMEMALLOC | __GFP_NOWARN); + if (prev) + prev->next = NULL; + } if (!prev) { more++; continue; |