diff options
Diffstat (limited to 'guix/store.scm')
| -rw-r--r-- | guix/store.scm | 30 |
1 files changed, 24 insertions, 6 deletions
diff --git a/guix/store.scm b/guix/store.scm index 1ab2b08b47..0463b0e8fa 100644 --- a/guix/store.scm +++ b/guix/store.scm @@ -1358,11 +1358,28 @@ on the build output of a previous derivation." (define (map/accumulate-builds store proc lst) "Apply PROC over each element of LST, accumulating 'build-things' calls and coalescing them into a single call." - (define result - (map (lambda (obj) - (with-build-handler build-accumulator - (proc obj))) - lst)) + (define accumulation-cutoff + ;; Threshold above which we stop accumulating unresolved nodes to avoid + ;; pessimal behavior where we keep stumbling upon the same .drv build + ;; requests with many incoming edges. See <https://bugs.gnu.org/49439>. + 30) + + (define-values (result rest) + (let loop ((lst lst) + (result '()) + (unresolved 0)) + (match lst + ((head . tail) + (match (with-build-handler build-accumulator + (proc head)) + ((? unresolved? obj) + (if (> unresolved accumulation-cutoff) + (values (reverse (cons obj result)) tail) + (loop tail (cons obj result) (+ 1 unresolved)))) + (obj + (loop tail (cons obj result) unresolved)))) + (() + (values (reverse result) lst))))) (match (append-map (lambda (obj) (if (unresolved? obj) @@ -1370,6 +1387,7 @@ coalescing them into a single call." '())) result) (() + ;; REST is necessarily empty. result) (to-build ;; We've accumulated things TO-BUILD. Actually build them and resume the @@ -1382,7 +1400,7 @@ coalescing them into a single call." ;; unnecessary. ((unresolved-continuation obj) #f) obj)) - result)))) + (append result rest))))) (define build-things (let ((build (operation (build-things (string-list things) |