Private mapped ashmem doesn't install vm fault handler.
So, do_anonymous_page is called for handling fault in handle_pte_fault().
This type of backed memory isn't related to asma->file which is used by
ashmem shrinker. Shrinking unpinned area for this mapping
will not shrink memory actually.
Although it's memory doesn't actually removed, pin status will
return ASHMEM_WAS_PURGED. So application will re-load content.
This is needless overhead, so invalidate pin/unpin ioctl behavior for
private map.
CC: John Stultz <john.stultz@xxxxxxxxxx>
CC: Brian Swetland <swetland@xxxxxxxxxx>
CC: Colin Cross <ccross@xxxxxxxxxxx>
CC: Arve Hjønnevåg <arve@xxxxxxxxxxx>
CC: Dima Zavin <dima@xxxxxxxxxxx>
CC: Robert Love <rlove@xxxxxxxxxx>
Signed-off-by: Joonsoo Kim <js1304@xxxxxxxxx>
diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c
index 634b9ae..2fde9df 100644
--- a/drivers/staging/android/ashmem.c
+++ b/drivers/staging/android/ashmem.c
@@ -49,6 +49,7 @@ struct ashmem_area {
struct file *file; /* the shmem-based backing file */
size_t size; /* size of the mapping, in bytes */
unsigned long prot_mask; /* allowed prot bits, as vm_flags */
+ bool shared_mapping; /* mapping type */
};
/*
@@ -327,6 +328,7 @@ static int ashmem_mmap(struct file *file, struct vm_area_struct *vma)
fput(asma->file);
goto out;
}
+ asma->shared_mapping = 1;
}
if (vma->vm_file)
@@ -614,21 +616,35 @@ static int ashmem_pin_unpin(struct ashmem_area *asma, unsigned long cmd,
pgstart = pin.offset / PAGE_SIZE;
pgend = pgstart + (pin.len / PAGE_SIZE) - 1;
- mutex_lock(&ashmem_mutex);
+ if (asma->shared_mapping) {
+ mutex_lock(&ashmem_mutex);
- switch (cmd) {
- case ASHMEM_PIN:
- ret = ashmem_pin(asma, pgstart, pgend);
- break;
- case ASHMEM_UNPIN:
- ret = ashmem_unpin(asma, pgstart, pgend);
- break;
- case ASHMEM_GET_PIN_STATUS:
- ret = ashmem_get_pin_status(asma, pgstart, pgend);
- break;
- }
+ switch (cmd) {
+ case ASHMEM_PIN:
+ ret = ashmem_pin(asma, pgstart, pgend);
+ break;
+ case ASHMEM_UNPIN:
+ ret = ashmem_unpin(asma, pgstart, pgend);
+ break;
+ case ASHMEM_GET_PIN_STATUS:
+ ret = ashmem_get_pin_status(asma, pgstart, pgend);
+ break;
+ }
- mutex_unlock(&ashmem_mutex);
+ mutex_unlock(&ashmem_mutex);
+
+ } else {
+ switch (cmd) {
+ /* if it is private map, pin/unpin have no impact to vm */
+ case ASHMEM_PIN:
+ case ASHMEM_UNPIN:
+ ret = ASHMEM_NOT_PURGED;
+ break;
+ case ASHMEM_GET_PIN_STATUS:
+ ret = ASHMEM_IS_PINNED;
+ break;
+ }
+ }
return ret;
}
--
1.7.9.5
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