On (24/02/07 09:25), Barry Song wrote:
> From: Barry Song <v-songbaohua@xxxxxxxx>
>
> Firstly, there is no need to keep zcomp_strm's buffers contiguous
> physically.
>
> Secondly, The recent mTHP project has provided the possibility to
> swapout and swapin large folios. Compressing/decompressing large
> blocks can hugely decrease CPU consumption and improve compression
> ratio. This requires us to make zRAM support the compression and
> decompression for large objects.
> With the support of large objects in zRAM of our out-of-tree code,
> we have observed many allocation failures during CPU hotplug as
> large objects need larger buffers. So this change is also more
> future-proof once we begin to bring up multiple sizes in zRAM.
>
> Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
Reviewed-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Note:
Taking it in NOT because of the out-of-tree code (we don't really
do that), but because this is executed from CPU offline/online
paths, which can happen on devices with fragmented memory (a valid
concern IMHO).
Minchan, if you have any objections, please chime in.
> @@ -37,7 +38,7 @@ static void zcomp_strm_free(struct zcomp_strm *zstrm)
> {
> if (!IS_ERR_OR_NULL(zstrm->tfm))
> crypto_free_comp(zstrm->tfm);
> - free_pages((unsigned long)zstrm->buffer, 1);
> + vfree(zstrm->buffer);
> zstrm->tfm = NULL;
> zstrm->buffer = NULL;
> }
> @@ -53,7 +54,7 @@ static int zcomp_strm_init(struct zcomp_strm *zstrm, struct zcomp *comp)
> * allocate 2 pages. 1 for compressed data, plus 1 extra for the
> * case when compressed size is larger than the original one
> */
> - zstrm->buffer = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
> + zstrm->buffer = vzalloc(2 * PAGE_SIZE);
> if (IS_ERR_OR_NULL(zstrm->tfm) || !zstrm->buffer) {
> zcomp_strm_free(zstrm);
> return -ENOMEM;
> --
> 2.34.1
>
