Fix alloc_pages() size claim in Lazy CMA blog post

The system heap actually uses order-8 (1MB) max allocations, not
MAX_ORDER (4-8MB) as previously stated.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: congwang-mk

_posts/2026-03-08-introducing-lazy-cma.md

@@ -17,7 +17,7 @@ There are two ways to configure CMA. You can set `CONFIG_CMA_SIZE_MBYTES` at ker
 
 This creates real operational friction. Cloud operators must predict memory needs ahead of time. Developers working with heterogeneous memory (CXL, PMEM) often cannot use CMA at all, because their memory is onlined post-boot and was never available during early reservation. And anyone using kdump must decide the crash kernel reservation size at boot, even though the optimal size depends on runtime conditions.
 
-The DMA-BUF system heap (`/dev/dma_heap/system`) takes a different approach and avoids boot-time reservation entirely. However, it relies on `alloc_pages()`, which is constrained by the buddy allocator's maximum order (typically MAX_ORDER pages, around 4MB to 8MB per allocation). To fulfill a large request, the system heap must issue many separate `alloc_pages()` calls and assemble the results into a scatter-gather list. For allocations of hundreds of megabytes or more, this becomes slow and prone to failure under memory pressure. Use cases like kexec, multikernel, and DAXFS need a single contiguous physical range far exceeding what the buddy allocator can provide in one shot.
+The DMA-BUF system heap (`/dev/dma_heap/system`) takes a different approach and avoids boot-time reservation entirely. However, it relies on `alloc_pages()`, which is constrained to order-8 allocations (1MB per chunk) in practice. To fulfill a large request, the system heap must issue many separate `alloc_pages()` calls and assemble the results into a scatter-gather list. For allocations of hundreds of megabytes or more, this becomes slow and prone to failure under memory pressure. Use cases like kexec, multikernel, and DAXFS need a single contiguous physical range far exceeding what the buddy allocator can provide in one shot.
 
 ## How Lazy CMA Works