STRUCT ANON_PIPE_PREALLOC(9)

🌸 NAME 🌸

okay bestie, this is the struct anon_pipe_prealloc(9) page from the Kernel API Manual — literally the per-pipe page preallocation pool. It's giving tiny page-stash energy, and we're gonna get you through it without the sleepy manpage voice. 🫶

✨ SYNOPSIS ✨

Here's the whole struct, verbatim, no cap:

       struct anon_pipe_prealloc {
           struct page *pages[PIPE_PREALLOC_MAX];
           unsigned int __data_racy count;
        };

🎀 Members 🎀

• pages — the array of cached pages, aka the pool itself. Yes, it's literally struct page *pages[PIPE_PREALLOC_MAX]; and it's iconic for that. 🎀
• count — the number of pages currently in the pool. It's declared as unsigned int __data_racy count;, so that's the exact little field right there. 💅

🦋 Description 🦋

So here's the tea: each pipe keeps a small bounded pool of preallocated pages to reduce allocation overhead during writes. The pool is bounded at PIPE_PREALLOC_MAX and trimmed down to PIPE_PREALLOC_KEEP after a write completes. That's the whole plot — no secret side quests, just preallocation doing its thing. ✨

🔥 SEE ALSO 🔥

Go peek at the Kernel file ./include/linux/pipe_fs_i.h, plus these cross-refs, bestie:

• struct pipe_buffer(9)
• union pipe_index(9)
• struct pipe_inode_info(9)
• pipe_has_watch_queue(9)
• pipe_occupancy(9)
• pipe_empty(9)
• pipe_full(9)
• pipe_is_full(9)
• pipe_is_empty(9)
• pipe_buf_usage(9)
• pipe_buf(9)
• pipe_head_buf(9)
• pipe_buf_get(9)
• pipe_buf_release(9)
• pipe_buf_confirm(9)
• pipe_buf_try_steal(9)

Source/version check: this cutie lives under ./include/linux, dated October 2026. Sign-off slay, bestie 💖✨