[..]
> static void *zcomp_lz4_create(void)
> {
> - return kzalloc(LZ4_MEM_COMPRESS, GFP_KERNEL);
> + void *ret;
> +
> + /*
> + * This function could be called in swapout/fs write path
> + * so we couldn't use GFP_FS|IO. And it assumes we already
> + * have at least one stream in zram initialization so we
> + * don't do best effort to allocate more stream in here.
> + * A default stream will work well without further multiple
> + * stream. That's why we use __GFP_NORETRY|NOWARN|NOMEMALLOC.
> + */
> + ret = kzalloc(LZ4_MEM_COMPRESS,
> + __GFP_NORETRY|__GFP_NOWARN|__GFP_NOMEMALLOC);
> + if (!ret)
> + ret = __vmalloc(LZ4_MEM_COMPRESS,
> + __GFP_NORETRY|__GFP_NOWARN|
> + __GFP_NOMEMALLOC|__GFP_ZERO,
> + PAGE_KERNEL);
> + return ret;
> }
[..]
so this change is still questionable. is there a real value in having
a vmalloc() fallback in the middle of allocations sequence:
zstrm = kmalloc(sizeof(*zstrm), GFP_NOIO);
^^^ ok, can fail here
zstrm->zstrm->private = comp->backend->create();
^^^ kzalloc() and vmalloc() fallback ??
zstrm->buffer = (void *)__get_free_pages(GFP_NOIO | __GFP_ZERO, 1);
^^^ can fail here again.
can you please comment on this?
and I'd prefer it to be a bit different -- use likely path first and
avoid an assignment in unlikely path.
... and add GFP_NOIO to both kzalloc() and __vmalloc().
and there is no __GFP_HIGHMEM in __vmalloc() call?
something like this:
---
ret = kzalloc(LZ4_MEM_COMPRESS, GFP_NOIO | __GFP_NORETRY |
__GFP_NOWARN | __GFP_NOMEMALLOC);
if (ret)
return ret;
return __vmalloc(LZ4_MEM_COMPRESS,
GFP_NOIO | __GFP_NOWARN | __GFP_HIGHMEM | __GFP_ZERO,
PAGE_KERNEL);
-ss
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