Re: [PATCH 0/2] mm/swap: hibernate: improve hibernate performance with new allocator

[Kairui Song]

On Sun, Feb 15, 2026 at 6:25 PM Kairui Song <ryncsn@xxxxxxxxx> wrote:
>
> The new swap allocator didn't provide a high-performance allocation
> method for hibernate, and just left it using the easy slow path. As a
> result, hibernate performance is quite bad on some devices
>
> Fix it by implementing hibernate support for the fast allocation path.
>
> This regression seems only happen with SSD devices with poor 4k
> performance. I've tested on several different NVME and SSD setups, the
> performance diff is tiny on them, but testing on a Samsung SSD 830
> Series (SATA II, 3.0 Gbps) showed a big difference [1]:
>
> Test result with Samsung SSD 830 Series (SATA II, 3.0 Gbps) thanks
> to Carsten Grohman [1]:
> 6.19:               324 seconds
> After this series:  35 seconds
>
> Test result with SAMSUNG MZ7LH480HAHQ-00005 (SATA 3.2, 6.0 Gb/s):
> Before 0ff67f990bd4: Wrote 2230700 kbytes in 4.47 seconds (499.03 MB/s)
> After 0ff67f990bd4: Wrote 2215472 kbytes in 4.44 seconds (498.98 MB/s)
> After this series: Wrote 2038748 kbytes in 4.04 seconds (504.64 MB/s)
>
> Test result with Memblaze P5910DT0384M00:
> Before 0ff67f990bd4: Wrote 2222772 kbytes in 0.84 seconds (2646.15 MB/s)
> After 0ff67f990bd4: Wrote 2224184 kbytes in 0.90 seconds (2471.31 MB/s)
> After this series: Wrote 1559088 kbytes in 0.55 seconds (2834.70 MB/s)
>
> The performance is almost the same for blazing fast SSDs, but for some
> SSDs, the performance is several times better.
>
> Patch 1 improves the hibernate performance by using the fast path, and
> patch 2 cleans up the code a bit since there are now multiple fast path
> users using similar conventions.
>
> Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
> Tested-by: Carsten Grohmann <carstengrohmann@xxxxxx>
> Link: https://lore.kernel.org/linux-mm/8b4bdcfa-ce3f-4e23-839f-31367df7c18f@xxxxxx/ [1]
> ---
> Kairui Song (2):
>       mm, swap: speed up hibernation allocation and writeout
>       mm, swap: merge common convention and simplify allocation helper
>
>  mm/swapfile.c | 56 ++++++++++++++++++++++++++------------------------------
>  1 file changed, 26 insertions(+), 30 deletions(-)
> ---
> base-commit: 53f061047924205138ad9bc315885255f7cc4944
> change-id: 20260212-hibernate-perf-fb7783b2b252
>
> Best regards,
> --
> Kairui Song <kasong@xxxxxxxxxxx>
>

Patch 1/2 is a wrong patch, sorry about this.

Just resent the series using B4 relay and marking it as V2 to
distinguish from this misformed one, please check that series instead,
thanks!
https://lore.kernel.org/linux-mm/20260215-hibernate-perf-v2-0-cf28c75b04b7@xxxxxxxxxxx/