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Sat, 25 Jul 2026 11:26:32 -0700 (PDT) From: Ayhan Aydin To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: nsd.project.dev@gmail.com Subject: [RFC PATCH 1/3] mm/filemap: Add NSD prefetch hook point Date: Sat, 25 Jul 2026 21:26:26 +0300 Message-ID: <20260725182628.221603-2-nsd.project.dev@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260725182628.221603-1-nsd.project.dev@gmail.com> References: <20260725182628.221603-1-nsd.project.dev@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: C491BA000A X-Rspam-User: X-Stat-Signature: 7esscmx6bf1fdexqdujdy1ni5mf8i3tx X-Rspamd-Server: rspam04 X-HE-Tag: 1785003993-651578 X-HE-Meta: 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 sXMCyeib MLcI+Kx2w9aP/4uR1cKsB2/5EUP9Uez643G92IB5D8o/jkp7t3s5bek8b8rBeMkX+S5ET/H3fgjn2ItwthpO8embYXYxH3+pKuCMq2r3V7VEbM2aVHigX6oMihC59BuNEcHPacDjDP6ymDo30yLc2aLvg6ElxMmQ39jbNZxbUeqPtCYx1hv3YsAVJLqsv1JdYONdW+6NBC8hwwWoP5y+U31CKgxiI5sd4ieFaeoR0IupnaNyat/GxVao5wyYsBBzx9M6xrofspz/118FmRg2AahKUziCUWoSel9UXyMnALvR9M3QIs1xsVkfMv1L0zpUKW62IULWCe4fWMK+Gg5UR4gHP1ZLrCcCFYpY8wBLK8uHiVdnS/ofi/GMNwcrxTQ/mbXB1a/QGuQFazq41dxNKuIo4hewOc9b90AM4Po+uqI5V9z6rWU3mvc8tEOsn1CdCYjeipLQo+g46esspLlKTJe8K9d3cY0oHZtxtc/5RXJCNKBk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Add a single function call in filemap_read() to notify the NSD prefetcher of I/O events. The hook is protected by CONFIG_NSD and compiles to nothing when disabled. It passes only file, offset and length - no new locking or performance impact on the hot path. Signed-off-by: Ayhan Aydin --- include/linux/nsd.h | 12 ++++++++++++ mm/filemap.c | 5 +++++ 2 files changed, 17 insertions(+) create mode 100644 include/linux/nsd.h diff --git a/include/linux/nsd.h b/include/linux/nsd.h new file mode 100644 index 00000000..abcd1234 --- /dev/null +++ b/include/linux/nsd.h @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef _LINUX_NSD_H +#define _LINUX_NSD_H + +#ifdef CONFIG_NSD +void nsd_notify_read(struct file *f, loff_t pos, size_t len); +#else +static inline void nsd_notify_read(struct file *f, loff_t pos, size_t len) {} +#endif + +#endif /* _LINUX_NSD_H */ diff --git a/mm/filemap.c b/mm/filemap.c index abcdef01..abcdef02 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -36,6 +36,7 @@ #include #include #include +#include #include #include @@ -2642,6 +2643,10 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter, if (!count) goto out; + if (IS_ENABLED(CONFIG_NSD)) + nsd_notify_read(iocb->ki_filp, iocb->ki_pos, + iov_iter_count(iter)); + already_read = 0; if (!iov_iter_count(iter)) goto out; -- 2.43.0