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b=Q0iheGUZYk8Pire/FtxwUk+x/f0XJwRMaH/KqUGIxTpGVbpAPhNgvKzF+ql3F9xCA NYWTy/SU73hZeRLV/MhPxMi2fWVbZFlHyQ52GjAVLy/pPezcruyaKCPSWndqVKOGVH tAj298QCenbJC3vP3c7sTKbccJ0vC5mDZIg8sscD3wmkJTlMnbpwxPqnmjT2xk6KKS vyP+0ZAQc6b1wG673FQwCLlN7NZ/1SmYpUbIXihQZLoYXr+ZGVK3u2XdGIWn+R9L6S 8Nx4PF6hjEahvS9GU58yOAbI42PhgcbOtHSQfPkJIrxUBUZGdot+u5gGp5nfyuDa4g WZ7z5qoHGbTZQ== From: Pratyush Yadav To: Pasha Tatashin Cc: Chenghao Duan , rppt@kernel.org, pratyush@kernel.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, jianghaoran@kylinos.cn Subject: Re: [PATCH v1 1/3] mm/memfd_luo: optimize shmem_recalc_inode calls in retrieve path In-Reply-To: (Pasha Tatashin's message of "Thu, 19 Mar 2026 11:28:05 -0400") References: <20260319012845.29570-1-duanchenghao@kylinos.cn> <20260319012845.29570-2-duanchenghao@kylinos.cn> Date: Fri, 20 Mar 2026 09:53:17 +0000 Message-ID: <2vxzms02bzea.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 15163180005 X-Stat-Signature: hdx8bxoxd9d7ktdmugnfxi49xgbm3jp9 X-Rspam-User: X-Rspamd-Server: rspam05 X-HE-Tag: 1774000401-490753 X-HE-Meta: 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 8HypcYhM AUYz9GLPzBApmw5IZqYPKVX6ykJnb7SCsceXngJFLSuPoU63YP9ZrlCom5MDfyqUtU+36gTSyx0P31sURnQ0cawNxT124yfeZAQIrhdGZruVNBONO+X0owtrPws2eE1zHDPfjSaJiS72LdS1QtpxLUif3Za2WRaehX25fbbkuvwVzksL62pNoHA0kYFEJwwKl2vbJWGWoBF2t4Cf1q8O0WogRu666TXDTZFqwSvc8rWTW8Dm/lqZZOM4VxAMgL5U0iGeYDe5AhZRJl0U= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Mar 19 2026, Pasha Tatashin wrote: > On Wed, Mar 18, 2026 at 9:29=E2=80=AFPM Chenghao Duan wrote: >> >> Move shmem_recalc_inode() out of the loop in memfd_luo_retrieve_folios() >> to improve performance when restoring large memfds. >> >> Currently, shmem_recalc_inode() is called for each folio during restore, >> which is O(n) expensive operations. This patch collects the number of >> successfully added folios and calls shmem_recalc_inode() once after the >> loop completes, reducing complexity to O(1). >> >> Additionally, fix the error path to also call shmem_recalc_inode() for >> the folios that were successfully added before the error occurred. >> >> Signed-off-by: Chenghao Duan >> --- >> mm/memfd_luo.c | 9 ++++++++- >> 1 file changed, 8 insertions(+), 1 deletion(-) >> >> diff --git a/mm/memfd_luo.c b/mm/memfd_luo.c >> index b8edb9f981d7..5ddd3657d8be 100644 >> --- a/mm/memfd_luo.c >> +++ b/mm/memfd_luo.c >> @@ -397,6 +397,7 @@ static int memfd_luo_retrieve_folios(struct file *fi= le, >> struct folio *folio; >> int err =3D -EIO; >> long i; >> + u64 nr_added =3D 0; > > nit: I perfer RCT for local variables order, but it is not followed in > this file anyway. It is though, for the most part. I also prefer this so as much as I could I followed it, but sometimes if you want to assign variables at declaration, it isn't always possible. Anyway, RCT would be nice to have indeed. [...] --=20 Regards, Pratyush Yadav